On the heels of the Kinesis Firehose announcement, more people are going to be looking to integrate Kinesis with logging systems. Here is one take on solving that problem that integrates syslog-ng with Kinesis.

What’s good about online schedulers is that you can get an access to your data from any of your devices. Your schedule will be safe if something happens to your laptop or smartphone. But the overall quantity of available schedulers can confuse you. There are JavaScript and .NET scheduling tools. There are third-party plug-ins for big frameworks and built-in parts of these frameworks. And finally, there are stand-alone tools which can be integrated with other components. This article’s aim is to take a look at the four most popular .NET scheduling components to make clear which of them is worthy of attention and good for beginners. Here are the scheduling tools: DayPilot ASP.NET Event Calendar DHTMLX Scheduler .NET Devexpress ASP.NET Scheduler Telerik .NET Scheduler We’ll use Microsoft Visual Studio 2013 to create demo applications. We will check how the basic calendar looks like and behaves. The other important thing is documentation. Good structured documentation pages with understandable step-by-step guides will be a plus. DayPilot ASP.NET Event Calendar DayPilot provides you with different kinds of time management tools: ASP.NET Event Calendar is an event calendar that allows you to plan your day hour by hour: ASP.NET Monthly Calendar will help you create a month schedule: ASP.NET Scheduler is useful if you want to group you events into different categories: ASP.NET Gantt Chart for those who want to build a Gantt Chart: Since Scheduler and Gantt Chart are more specialized tools we’ll take a look at something more commonly used. Let’s say, the Event Calendar. Basic features: Integrated message bar Drag-and-drop Export. Available file formats are BMP, PNG, GIF and JPG Customizable appearance The full list of features is available on this page. If you want to check what you can get from it, check this demo page. The tutorial page is a little bit messy at first sight. There are pages for different kinds of features for all of the DayPilot components. However, it’s not too hard to find the page you want. Which is, in our case, this basic calendar tutorial page. It’s a step-by-step guide which shows how to create a project in Visual Studio, create a database and attach it to your project, etc. It’s a little bit hard to get started with it if you haven’t used Visual Studio before. If you’re lazy enough, you can simply download the source code for this example here. After the job is done, you can check the results: You can’t do much with this simple event calendar. This testing event can be dragged through the calendar grid to change its beginning date. It was created during the calendar creation and by default, there’s no possibility to create a new one. To add this functionality you should spend some more time with tutorials. And you can’t change the scale of the calendar. Therefore, if you want to get a possibility to create long term events as well, you should use both Event Calendar and Monthly Calendar in your project. But here’s some good news. There is an open-source version of Event Calendar available. The cost of DayPilot calendar may vary from $499 to $4999 depending on the license and product version. Well, let’s move along. DHTMLX Scheduler .NET DHTMLX Scheduler .NET is another stand-alone tool that was made to help you create your own online scheduler. Check this demo page to see how it looks like. Basic features: Different views: Decade view, Grid view, Year view Recurring events Drag-and-drop Touchscreen support Easy customizable Integration with Google Maps and Google Calendar You can check all its features on this page. There is more than one possible way to get this scheduler. You can download the package with required files or install them via NuGet or Package Manager Console. This install guide can help you choose the proper way. Let’s talk about documentation. Since DHTMLX Scheduler .NET is basically a .NET wrapper for this JavaScript scheduler, the documentation consists of two parts: server side and client side articles. There are basic calendar creation guides and a bunch of configuration guides. Moreover, there is a video tutorial available. But what we’re interested in right now is how we can create a basic calendar. The developer’s blog contains this tutorial explaining how to build a basic calendar in ASP.NET MVC5. It’s quite detailed and contains a bunch of screenshots. And here’s what we got: This time we can change the scale. There are “Day”, “Week” and “Month” buttons available. The current day is highlighted and there is a “Today” button that will help you in case you lost yourself within the calendar grid. There are several ways of how you can create a new task. You can use drag-and-drop with this calendar. So, select the time period you want and the event property window will appear on your screen: You can also use right click to get access to this window, but in this case you’ll have to set the time period by yourself. Scale changing feature is useful if you want to create a long term event: You can drag the event to change its start date. This is all that you can get by default. The important thing is that, unlike the DayPilot tool, this scheduler can be used to show days, weeks and months. This basic app, as you can see, gives you a possibility to add and change the tasks. Documentation structure is easy to understand, so it’s not too hard to use it to improve your application. The cost of DHTMLX Scheduler .NET is $299 for Commercial License and $979 for Enterprise license. Devexpress ASP.NET Scheduler DevExpress provides you with huge amount of different tools. There are WinForms, iOS, ASP.NET components for desktop and online applications. Very detailed subscription of Devexpress scheduler is available on this page. You can get the installation file on this download page. There’s no possibility to install the scheduler separately from other .NET and MVC components. There’s a lot of documentation. Tons of it. For every single component. The scheduler documentation page is separated into several parts: “Start Here”, Learn More”, “How To” and “Reference”. Each of them consists of chapters that contain a bunch of articles on a specific topic. Everything that you need to know about the every single tool. But if you want to create a basic scheduler fast, you can check two video tutorials available on YouTube: The Project Wizard which will tell you how to create a Devexpress project and Getting Started with the ASPxScheduler which is about the scheduler creation process. This 14 minutes is all that you need to create your first online application. The result is shown below: As you can see, there are a couple of scales available: “Day”, “Work Week”, “Full Week” and “Month”. Moreover, there is a Timeline mode, which can help you trace the current week events. A navigation panel on the right side will help you switch between month and years. Drag-and-drop behavior is available, so you can select the proper area of the calendar grid to create a new event. After the right-click you can choose what you want to do: The properties window will appear. It allows you to set the basic properties (Start time, End time, Subject, etc.) and a couple of additional ones (Label, for example): According to these properties, different events will look differently, which is pretty handy. Here’s the Timeline mode as an example: The cost of Devexpress scheduer is $899.99 for the .NET bundle. Telerik .NET Scheduler Just like the previous developer, Telerik provides you with a wide variety of tools: a mobile application platform for iOS, Android and Windows Mobile; HTML5 and JavaScript widgets for web applications; .NET components for desktop, mobile and online applications and much more. But we’re here for one reason. RadScheduler page contains a detailed list of features with a demo page for each of them. And, like in case of Devexpress, this time we can’t download the scheduler separately. We should get the whole .NET bundle. The documentation page contains comprehensive information about available components. There are tutorials, API documentation, videos, infographics and other useful stuff. It may be a little bit complicated to define where to start from. But there is a YouTube video tutorial that allows you to dive straight into the action instead of reading tons of docs. First 13 minutes are enough to get required basic information about how the things work. As a result you will get something like this: There is something familiar with this one. We can choose between “Day”, “Week”, “Month” and “Timeline” modes. The last one works pretty much the same as the Devexpress Timeline option. This time we have a mini calendar which is useful for navigation. There’s also a “Show full/business hours” toggle button that allows you to separate your work events from the private ones: New event creation is intuitive and similar to other calendars. This time there is a wide variety of properties that allows you to configure the recurrent events. And, as usual, drag-and-drop is available. The cost of Telerik scheduler is $999 for the .NET bundle. Conclusion Described schedulers can be divided into two groups. The first two of them are stand-alone tools. In case of DayPilot there’s no possibility to get the calendar you like. The only possible way to get it is to buy the whole bundle. DHTMLX Scheduler .NET is the only component that can be bought separately from any other tool, which is great if you’re not interested in additional components. The remaining two components are the part of big .NET bundles. And maybe it’s not a good idea to buy them if you want to create a simple online calendar. DayPilot and DHTMLX Scheduler .NET DayPilot components look great. The documentation contains detailed tutorials. The bad thing is that the basic scheduler which was built according to the beginner’s guide is kinda low functional. To make something really useful you should spend some more time with it. There’s also no possibility to change the scale of a calendar, so you have to chose either Event Calendar or Monthly Calendar to plan your events properly. The good news is that, besides the paid components, there is an open-source version available. You can get it here. DHTMLX Scheduler .NET is more attractive, especially for beginners. There are step-by-step guides of different levels of complexity and a video tutorial. The basic app looks pretty useful. It allows you to change the calendar scale, add and configure the tasks. There are Commercial and Enterprise versions available on this page. You can also get the 30-days trial version. As an alternative, you can try the JavaScript version of this scheduler. You have two options with this one: commercial Pro Edition and open-source Standard edition. Devexpress ASP.NET Scheduler and Telerik .NET Scheduler Those two are the components of big and advanced sets of tools. They’re integrated with Visual Studio. As a result, there’s a project wizard for both of them that allows you to configure your application properties. The documentation contains dozens of pages and it may confuse you at the first glance. But you can find an article about the every single property if you spend some time with it. There are video tutorials available as well, so everyone can find the most convenient way of learning. The Devexpress documentation structure looks more comfortable. Every big theme is separated into several parts which are grouped according to the difficulty level. The basic scheduler is pretty functional. For example, there is a possibility to set a proper label for a task. There are a lot of possible combinations of tools that you can buy. But it’s always good to try some before to make a decision and trial versions will help you with that. Check the details on this page. Telerik documentation is not so well grouped which can confuse the beginners. Scheduler creation is intuitive and the basic app is pretty usable. Just like in the previous case, Telerik provides you with a wide variety of possible bundles of tools. And, once again, you can try it before buy it. Trial versions are waiting for you.

[This article was written by Juergen Hoeller.] Spring is well-known to actively support the latest versions of common open source projects out there, e.g. Hibernate and Jackson but also common server engines such as Tomcat and Jetty. We usually do this in a backwards-compatible fashion, supporting older versions at the same time - either through reflective adaptation or through separate support packages. This allows for applications to selectively decide about upgrades, e.g. upgrading to the latest Spring and Jackson versions while preserving an existing Hibernate 3 investment. With the upcoming Spring Framework 4.2, we are taking the opportunity to support quite a list of new open source project versions, including some rather major ones: Hibernate ORM 5.0 Hibernate Validator 5.2 Undertow 1.2 / WildFly 9 Jackson 2.6 Jetty 9.3 Reactor 2.0 SockJS 1.0 final Moneta 1.0 (the JSR-354 Money & Currency reference implementation) While early support for the above is shipping in the Spring Framework 4.2 RCs already, the ultimate point that we’re working towards is of course 4.2 GA - scheduled for July 15th. At this point, we’re eagerly waiting for Hibernate ORM 5.0 and Hibernate Validator 5.2 to GA (both of them are currently at RC1), as well as WildFly 9.0 (currently at RC2) and Jackson 2.6 (currently at RC3). Tight timing… By our own 4.2 GA on July 15th, we’ll keep supporting the latest release candidates, rolling any remaining GA support into our 4.2.1 if necessary. If you’d like to give some of those current release candidates a try with Spring, let us know how it goes. Now is a perfect time for such feedback towards Spring Framework 4.2 GA! P.S.: Note that you may of course keep using e.g. Hibernate ORM 3.6+ and Hibernate Validator 4.3+ even with Spring Framework 4.2. A migration to Hibernate ORM 5.0 in particular is likely to affect quite a bit of your setup, so we only recommend it in a major revision of your application, whereas Spring Framework 4.2 itself is designed as a straightforward upgrade path with no impact on existing code and therefore immediately recommended to all users.

Rework is Hell “Software may be eating the world, but rework is choking software”, tweeted John Jeremiah (@j_jeremiah). To shed more light on what is choking software, new data was released last week in the 2015 State of the Software Supply Chain Report. In its discussion of application quality and integrity, the report revealed that the average application includes 106 open source components. It is clear that the use of these components has benefited development tremendously in helping to speed time to market and improve innovation. While the benefits are undeniable, development teams are also delivering applications that are “insecure by design”. Of the 106 components per application, the report’s analysis revealed an average of 24 (i.e., 23%) have known critical or severe security vulnerabilities. Those same apps also showed an average of 9 restrictive license types (e.g., GPL, AGPL, LGPL). By electively sourcing components with known vulnerabilities and potential license risks, software development teams are building up higher levels of technical and security debt. And in order to reduce some of that debt, unplanned and unscheduled rework is often required. No Developer Intentionally Uses Bad Parts I have never met a developer that intentionally wanted to use “bad” components in their applications. That said, I have also never met a developer that wanted to spend four hours researching the latest versions, open source licenses and known security vulnerabilities for components (including dependencies) they wanted to use in their applications. While 57% of development organizations have internal policies in place that direct “thou shall not use components with poor quality and integrity”, many have stated that the policies are not followed or are simply not enforced. The problem is one of volume and velocity, while people clutch to old processes that simply can’t keep pace. The analysis in the 2015 State of the Software Supply Chain report revealed that billions of open source downloads occurred in 2014, of which 6.2% had known vulnerabilities (1 in 16 downloads). For some large companies, the volume of downloads exceeded 240,000 — where 15,000 (7.5%) had known security vulnerabilities. At these volumes, manual processes and paper-based policies to prevent poor quality or risky components from getting into your software have no possibility of keeping pace. While software development practices aim for higher velocity, through component-based development as well as Agile, continuous and DevOps practices, the processes to keep up with it have not changed enough. The only way to keep pace with this velocity is through automation. And if we want to avoid unplanned rework associated with remediating known security vulnerabilities or selecting alternative components with approved license types, automation has to become the norm rather than the exception within development. At Speed “If I look at the mass, I will never act. If I look at the one, I will.” — Mother Teresa Looking at the massive volume and velocity of open source and other artifact consumption can be discouraging and overwhelming. However, the volume and velocity within our software supply chains will not diminish—and without a new approach, the volume of unchecked quality and integrity of parts being consumed will continue to build up as technical debt. Automation in areas of testing, build, and deployment has provided significant performance benefits. Likewise, investments in software supply chain automation have shown markedly improved efficiency and controlled risk, as the best practices in the 2015 Report illustrate. Automation can unleash the potential of an organization’s development capacity. Rarely is there such an opportunity to simultaneously increase speed, efficiency, and quality. In order to improve the quality and integrity of components used in our applications, we need to release our clutch on old practices. We can further embrace automation across our software supply chains — and improve the quality of our applications — by considering these three steps: 1. Start with creating a software bill of materials for one application. Visibility into one application can help you better understand your current component usage. A number of free and paid services are available to help you create a software bill of materials within a few minutes. The bill of materials will help you to identify the unique component parts used within your application and the suppliers who contributed them. These reports list all components used, and several services also identify component age, popularity, version numbers, licenses, and known vulnerabilities. 2. Design approval processes to be frictionless, scalable, and automated. Manual reviews of components and suppliers cannot keep pace with the current volume and velocity of consumption. Your organization must not only define your policies for supplier and part selection but also find practical ways to enforce them without slowing down development or inadvertently encouraging workarounds. Policies must be agile enough to keep pace with modern development. Strive to automate policy enforcement and minimize drag on developers. 3. Enable developer decision support. Developers are primary consumers of components in software supply chains. They initiate every component request. Help developers by automating the availability of information on component versions, age, popularity, licenses, and known vulnerabilities within their existing development tools so it is easy to pick the best components from the start. By selecting the highest-quality components from the highest-quality suppliers early, you will improve developer productivity and reduce costs. Here is the complete 2015 State of the Software Supply Chain Report. I will also be discussing more of the Report findings and best practices on a webinar scheduled for Wednesday, June 24, 12pm ET (register or view it on-demand). The previous blog in this series was, Fewer and Better Suppliers. Next up, I will be reviewing Visibility and Traceability practices across the software supply chain with more commentary from the 2015 State of the Software Supply Chain Report.

That Supplier is Better For You Since releasing the 2015 State of the Software Supply Chain Report, there has been a lot of great discussion across the industry on best practices for managing the complexity introduced by the volume and velocity of the components used across your software supply chain. Today I want to focus on the huge ecosystem of open source projects (“suppliers”) that feed a steady stream of innovative components into our software supply chains. In the Java ecosystem alone, there are now over 108,000 suppliers of open source components. Across all component types available to developers (e.g., RubyGems, NuGet, npm, Bower, PyPI, etc.), estimates now reach over 650,000 suppliers of open source projects. Source: ModuleCounts.com However, like in traditional manufacturing, not all suppliers deliver parts of comparable quality and integrity. My latest research, the 2015 State of the Software Supply Chain Report, shows that some open source projects use restrictive licenses and vulnerable sub-components, while other projects are far more diligent at updating the overall quality of their components. Choosing the best and fewest suppliers can improve the quality and integrity of the applications we deliver to our customers. While I am hosting a webinar next week to share many of the detailed report findings, I wanted to share a few of the more meaningful stats here. Your 7,600 Suppliers My research for the report revealed many new perspectives on “suppliers” across the software supply chains. First of all, I saw that the average large development organization consumed over 240,000 open source components last year — sourced from over 7,600 open source projects. Average number of open source component downloads per organization in calendar 2014 On the surface, the huge reliance on open source projects is a great thing. Development teams have chosen to not write those pieces themselves, but have sourced the needed components from outside suppliers. This practice speeds development, enables more innovation, and ensures time-to-release goals are achieved. The use of open source is so prolific today, few of us could ever imagine reducing the use of those components and their suppliers in the future. At the same time that we benefit from open source, our high paced, high volume consumption practices don’t allow us the time needed to do the due diligence on the suppliers or open source projects where we source our component parts from. Average number of known vulnerabilities downloaded by organization in calendar 2014. For example, of the 240,000 average component downloads in 2014, the same businesses sourced an average of 15,000 components that included known security vulnerabilities. In many cases, developers were downloading vulnerable component versions, when safer versions of those same components were available from the open source projects. While no one intends to download components with known vulnerabilities, the problem is exacerbated due to the lack the visibility into a better recommended version. Fewer Suppliers, Less Context Switching Choosing an open source project supplier should be considered an important strategic decision in organizations because changing a supplier (“open source project”) used is far more effort than swapping out a specific component. Like traditional suppliers, open source projects have good and bad practices impacting the overall quality of their component parts. Traditional manufacturing supply chains intentionally select specific parts from approved suppliers. They also rely on formalized sourcing and procurement practices. This practice also focuses the organization on using the best and fewest suppliers — an effort that improves quality, reduces context switching, and also accelerates mean time to repair when defects are discovered. One industry example from the report describes how Toyota manages 125 suppliers for their Prius to help sustain competitive advantages over GM who manages over 800 suppliers for the Chevy Volt. By contrast, development teams working with software supply chains often rely on an unchecked variety of supply, where each developer or development team can make their own sourcing and procurement decisions. The effort of managing over 7,600 suppliers introduces a drag on development and is contrary to their need to develop faster as part of agile, continuous delivery and devops practices. Coming to Terms When you come to terms with the volume of consumption and the massive ecosystem of suppliers you can source your components from, you quickly realize it is impossible to address this issue with a manual review process. Any organizations clutching to these outdated manual practices are will continue to be outgunned by the velocity by their software supply chains. Just as traditional manufacturing supply chains have turned to automation, software development teams need to take the same approach by further automating their software supply chains. Information about suppliers and the quality of their projects needs to be made available to developers at the time they are selecting components. Information about the latest versions, features, licenses, known vulnerabilities, popularity of versions being used, and the cadence of new releases should be made available to developers in an automated way. Automating the availability of this information about suppliers can lead to better and fewer suppliers being used. Be sure to read the full 2015 State of the Software Supply Chain Report for more information about open source suppliers and organizations sourcing practices. The report also highlights current and best practices being used in organizations that are managing their use of suppliers that feed their software supply chains.

The use of OpenStack in the private cloud is invaluable for DevOps. It provides engineers the ability to innovate quickly and deal with uncertainty. It also maximizes existing infrastructure and provides a programmable, software-defined IaC. Openstack in the private cloud = agile development OpenStack has emerged as the de facto standard for IaaS in the private cloud. It gives engineers a vital self-service capability to provision (and de-provision) environments, allowing them to act autonomously, in the moment. This helps to eliminate the downstream bottleneck caused by waiting for operations staff to find time to do the provisioning. As OpenStack is open source it is vendor agnostic, allowing you to take advantage of competitive pricing rather than suffering from vendor lock-in. A private cloud means lower cost for the same capacity in a public cloud, which is especially useful for enterprises with high data needs. For security reasons, OpenStack is still mainly used in the private cloud by developers and QA, i.e. in a non-production context. However, OpenStack gives an ability to optimize application performance and/or security by having more control compared to public cloud. The software is increasingly backed by the critical mass of leading IT infrastructure vendors such as IBM, CICSO and HP. Gartner assumes that “by 2019, OpenStack enterprise deployments will grow tenfold, up from just hundreds of production deployments today, due to increased maturity and growing ecosystem support.”1 Challenges to consider OpenStack implementation skills are still rare in the market, so experimentation and self-learning is necessary. Although this takes time, it is offset by the fact the software is free and represents a good opportunity to gain internal expertise. This is particularly valid if you class infrastructure as a core competence. The maturity and functionality of OpenStack projects vary widely - while it covers storage, network and compute, the main adoption currently happens around compute (Nova) and block storage (Cinder), with object storage and network (Neutron) lacking significantly behind. However, without leveraging virtualized network services as part of a private cloud, full-stack environment provisioning is not possible, so don’t forget to add necessary network services to your private cloud. Where to begin Integrating OpenStack clouds with existing infrastructure can be a challenge. It is hardly plug and play. At first, it is best to focus on relatively isolated DevOps environments, such as Gartner’s “mode two”2 applications rather than introducing open stack across the board straight away, (Bimodal IT “refers to having two modes of IT, each designed to develop and deliver information – and technology – intensive services in its own way. Mode 1 is traditional, emphasizing scalability, efficiency, safety and accuracy. Mode 2 is nonsequential, emphasizing agility and speed.”3) As with any open source software, new functions and upgrades are frequently released. This means keeping up with changes in functionality and filling gaps with customizations or third-party products. Upgrades are complex and typically require planned downtime. For these reasons, we recommend choosing a hardened distribution and sticking with it. Openstack is the most complete vendor agnostic solution for storage, network and compute services. The ability for developers to instantly spin up environments at any time is invaluable for a fully agile DevOps environment, and is well worth the effort it takes to acclimatize to Openstack. 1 http://www.prnewswire.com/news-releases/suse-openstack-cloud-5-to-simplify-private-cloud-management-300048721.html 2 http://www.gartner.com/it-glossary/bimodal 3 http://www.gartner.com/it-glossary/bimodal

[This article was written by Ophir Prusak] Guest author Ophir Prusak is chief evangelist atBlazeMeter. To learn more about load and performance testing automation, he invites readers toattend a meetupthis Wednesday, June 24, at New Relic’s San Francisco offices. Performance and load testing are kind of like flossing your teeth. You know you need to do it, but you might not be doing it as much as you should. When your site goes down because it couldn’t handle the load, you look back and realize you might have easily prevented it with a little more testing in advance. That’s why companies are automating their application testing in an effort to lower costs, increase efficiency, and reduce the time needed to release new features. The importance of automated testing in a continuous delivery era Continuous Delivery (CD) is rapidly emerging as the “new normal” in software development, as Perforce discovered in an independent survey, with an estimated 80% of SaaS companies and 51% of non-SaaS companies adopting this practice. Companies that provide Software-as-a-Service know they need to be continuously creating new features, updating their websites, and optimizing their backend. But while software development has adapted nicely in terms of automation, the testing side has moved more slowly. For a fully Continuous Delivery and Integration process to be realized, performance testing must be automated. As the need for testing increases, doing it manually can dramatically increase your time to release. Automating testing throughout the CD process can help detect errors instantly and deliver software faster. Making it work JMeter is the de facto standard in open source load testing. It’s the most widely used open source tool for performance testing for a good reason. There’s virtually nothing it can’t test (websites, native mobile applications, APIs, and Web applications) and it’s extremely powerful and fully featured. Yet there are challenges. JMeter poses a steep learning curve in terms of integration and ease of use. Additionally, it doesn’t integrate easily with APM and Continuous Integration (CI) tools. Many developers have been looking for a way to conduct performance testing with less time and effort—and fewer hiccups along the way. Taurus: An effort to simplify test automation A new open source project called Taurus (Test AUtomation Running Smoothly) is designed to provide exactly that—a way to remove most of the pain of using JMeter on its own. Taurus can give you the ability to Create and define a load test even without using JMeter. Override existing JMeter files or tests configurations. Create human-readable configuration files and testing scripts that are easily added to source control systems like GitHub. Integrate into CI tools like Jenkins. Run multiple tests in parallel. Provide pass/fail criteria back into the CI tool for easier automation of test-results analysis. Make analysis of test results easier and more intuitive. Taurus still uses JMeter under the hood, but is designed to have a much easier learning curve, especially for simple tests. Taurus also offers a built-in result analysis engine that provides both console-based reporting features and result analysis. Performance testing and optimizing your applications is not simple, yet there are solutions available that make the process easier and more successful. I’m looking forward to seeing how the technology evolves even further in the near future. If you want to learn more about Taurus, check out the project on GitHub. Better yet, you are invited to come to a meetup this Wednesday, June 24, at New Relic’s San Francisco offices. You can learn a lot more about Taurus and how you can use it to help scale load and performance testing automation.

What is strus ? The project strus is a collection of libraries and tools written in C++ to build a competitive search engine. Currently it is a single person project that started in September 2014 and therefore the competitiveness in terms of features of the software is more a promise than a fact. It definitely needs more brain to be put into it to catch up with the big players for open source search engines Lucene and Xapian. But strus is not only a me-too-project for search. Strus introduces expression matching and information extraction on a different level than other known open source engines (read more…). Strus simplifies the architecture of a search engine by “outsourcing” of components like the key/value store database storing the data blocks. This componentization (see components of strus) reduces the amount of code drastically and it raises opportunities for experts on a specific topic to contribute (read more…). Strus is not the first attempt to try that, but it is the first attempt as open source project, that has a performance within reach of the big open source search engines. And it does that without a 10 years history of optimization in the back. Strus might not be there at eye level, but let’s see what happens, if more different reasoning and competition is put into it. For who is strus ? People I would primarily like to address with this blog are developers or hackers as potential contributors or for feedback. On the other hand the project could already be interesting for experimental projects that can afford to go along with the development of strus. As stakeholder you can influence the project too. As the demo project, the search on the complete Wikipedia collection (English) shows, it is already possible to build projects, but you have to be aware, that dead lines should not exist, because you might hit a point where a feature you need is not instantaneously available. Project planning gets difficult at the current stage. Furthermore the state of documentation is still quite poor. Programming paradigms All interfaces of strus are pure. No inheritance is used in the main header files. Strus is more a lego thing than a provider of solution classes. If you want for example to build a sequence of terms as feature for your search, you have to build its expression tree with help of a stack, rather than picking a class that implements a sequence query. In PHP this looks as follows: $terms = [ “hello”, “world” ]; $query->pushTerm( “word”/*feature type*/, $term[0] ); $query->pushTerm( “word”/*feature type*/, $term[1] ); $query->pushExpression( “sequence”, 2/*nof terms*/, 2/*position range*/); $query->defineFeature( “docfeat” /*name addressing this feature set*/); The number of interface classes is small (see for example the interface classes of the core), but you have to understand them. If you want to contribute, you should also have a closer look at the programing guidelines. Try it There exist a guide how to fetch, build and install strus. Unfortunately a tutorial is still missing. There will be one soon ! Support I will reply to questions. Please mail me to contact at project dash strus dot net. Thanks I want to thank the authors of LevelDB here. I was looking for some time for a key/value store database that had an upper bound seek function in the interface. The upper bound seek is crucial because it allows you to minimize block accesses on disk when joining sets. A key/value store without upper bound seek would have forced me to create virtual blocks that point to other blocks. This would mean more disk accesses to fetch the data blocks needed. LevelDB has it. Any other alternative candidate to implement the database interface has to have it too. Social Media Github: patrickfrey Twitter: @ProjectStrus

Survey of open source PostgreSQL users found adoption continues to rise with 55% of users deploying it for mission-critical applications Bedford, MA – June 23, 2015 – EnterpriseDB (EDB), the leading provider of enterprise-class Postgres products and database compatibility solutions, today announced the results of its “PostgreSQL Adoption Survey 2015,” a biennial survey of open source PostgreSQL users. Conducted by EnterpriseDB, the survey found PostgreSQL adoption continuing to rise, with 55% of users – up from 40% two years ago – deploying it for mission-critical applications and 77% of users are dedicating all new application deployments to PostgreSQL. These findings give voice to end users and confirm such industry indicators as increasing job listings and monthly rankings on DB-Engines that have pointed to rising interest in and demand for PostgreSQL, also called Postgres. The growing popularity of Postgres also comes as traditional software vendors suffer setbacks in the marketplace. The enterprise-class performance, security and stability of Postgres, on par with traditional database vendors for most corporate workloads, meanwhile have helped position Postgres among the solutions from the world’s largest vendors. The opportunity to transform their data center economics has helped fuel downloads of Postgres as well. End users reported cutting costs with Postgres, with 41% reporting they had first-year cost savings of 50% or more. They’re using Postgres to build web 2.0 applications using unstructured data as evidenced by the 64% of respondents who said they were working with JSON/JSONB and the 47% who said they were using Postgres for collaboration applications. “Postgres is empowering organizations to transform the economics of IT. IT can invest in the customer engagement applications that differentiate their operations from their competition instead of continuing to pay the steep and rising licensing and support fees charged by traditional database vendors,” said Marc Linster, senior vice president of products and services of EnterpriseDB. “With the expanding adoption, EnterpriseDB has experienced dramatic growth year over year, providing the software, services and support that organizations need to be successful with Postgres.” Database Migrations, Replacements The findings also support statements in a recent Gartner report that reflect the widespread acceptance of open source databases. “By 2018, more than 70% of new in-house applications will be developed on an OSDBMS, and 50% of existing commercial RDBMS instances will have been converted or will be in process,” according to the April 2015 Gartner report, The State of Open-Source RDBMs, 2015.* Among Postgres users, the survey findings show migrations are already under way with 37% reporting they had migrated applications from Oracle or Microsoft SQL Server to Postgres. Many users were still planning further migrations, with 37% of PostgreSQL users saying they will gradually replace their legacy systems with Postgres, compared to 29% who said that in the 2013 survey. Further, end users predict their deployments of Postgres will expand significantly, with 32% saying they anticipate production deployments of Postgres to increase by at least 50% over the next year. The survey, conducted by EnterpriseDB using an online tool in May 2015, queried registered users of PostgreSQL and drew 274 respondents worldwide from government organizations and companies ranging in size and industry. *The State of Open-Source RDBMs, 2015, by Donald Feinberg and Merv Adrian, published on April 21, 2015. Connect with EnterpriseDB Read the blog: http://blogs.enterprisedb.com/ Follow us on Twitter: http://www.twitter.com/enterprisedb Become a fan on Facebook: http://www.facebook.com/EnterpriseDB?ref=ts Join us on Google+: https://plus.google.com/108046988421677398468 Connect on LinkedIn: http://www.linkedin.com/company/enterprisedb

[This article was written by Kevin Casey] Welcome to This Week in Modern Software, orTWiMS, New Relic’s weekly roundup of the need-to-know news, stories, and events of interest surrounding software analytics, cloud computing, application monitoring, development methodologies, programming languages, and the myriad of other issues that influence modern software. This week, our top story goes inside President Obama’s secret team of tech geeks, 140 of them and counting: TWiMS Top Story: Inside Obama’s Stealth Startup—Fast Company What it’s about:If the President of the United States walked into the room and personally recruited you to rebuild the country’s technology infrastructure, could you turn him down? He’s serious, and that room is theRoosevelt Room in the West Wing of the White House, by the way. AsLisa Gelobtersays: “What are you going to say that?” Gelobter’s answer was “Yes”—she’s now chief digital officer for the US Department of Education, part of a 140-person-and-counting tech team that’s functioning something like an elite startup embedded inside the federal government. Its business? Only modernizing the technical infrastructure, applications, and processes of just about every federal agency. Why you should care:What was once something of a tech desert—the federal government—is beginning to draw top private-sector talent inside the Beltway. The team, led by Mikey Dickerson (who helped lead the team that rescuedHealthcare.gov) andformer US CTO Todd Park, also includes the likes of former Googler Matthew Weaver, and it hopes to hit 500 people by the end 2016, shortly before President Obama will leave office. Its challenges are immense, from tackling government bureaucracy (to test just how entrenched the suits were, Weaver requested the official title “Rogue Leader”—and he got it) to the fact that its recruiting pitch includes the phrase: “You’ll have to take a pay cut.” But its mission is both noble and necessary, and the appeal of working on major problems with enormous public impacts appears to be working. Recommended reading. Further reading: Mikey Dickerson’s 10 Tips for Dealing with Bureaucracy—New Relic Blog [Video] Airbnb Open Sources Software to Lure Talent Amid ‘Insane’ Competition—CIO Journal What it’s about:Airbnb added three new apps to its open source portfolio earlier this month, but the motivation wasn’t just trying to give employees the best business tools or contribute to the software community at large. Sure, that might have been part of the equation, but the rental booking site hopes open-sourcing some of its toolkit will help recruit the best software talent in the face of what director of engineeringMike Curtiscalls “insane” competition in the Silicon Valley labor market. Why you should care:In the software arms race, any little edge counts. Curtis tellsCIO Journalthat Airbnb will keep the proprietary stuff closely guarded, of course. But it will open source “generic” tools with wider industry use cases, such as its recently releasedAerosolvemachine-learning package and itsAirpalcloud-based data querying tool. The latter, which works with Facebook’s open sourcePrestoDB, aims to simplify SQL queries to the point where you don’t need to be a big data wonk or business intelligence guru to run it. Indeed, one in three Airbnb employees have run a query on it in the year since it launched. Airbnb has contributed a dozen open source tools on its aptly namedNerds site(gotta love that!) to date, something the company hopes both contributes to greater good but also advertises its software innovation to potential hires. Google Is Wielding Its Own Secret Weapon in the Cloud—The New York Times What it’s about:In thecutthroat competitionfor public cloud business, Google may be its own best customer testimonial. In advance of this week’sOpen Network Summit, theTimes’Bits bloglooked at Google’s plan to not only unveil cloud customers such as HTC but reveal much more than ever before about its own infrastructure. Google did just that on Wednesday, offering a look inside itsdata center networking, including its massive-capacity, lightning-fast Jupiter network. Why you should care:As major cloud players continue to zap prices with their shrink-rays, it’s increasingly clear that features and underlying platforms will distinguish one from the other when enterprise users make their pick. Google is taking a big step toward writing its own story in this regard, and the synopsis might read something like: “We’re pretty good at this stuff.” Its Jupiter fabrics deliver 1 petabit per second of bisection bandwidth, according to Google, or “enough for 100,000 servers to exchange information at 10Gb/s each, enough to read the entire scanned contents of the Library of Congress in less than 1/10th of a second.” If it sounds like a bit of bragging, well, yeah—it is. But it’s bragging with a purpose: Attracting devs who want access to the same technology without having to build it themselves.Google’s Amin Vahdat connected the dots in a blog post: “The same networks that power all of Google’s internal infrastructure and services also power Google Cloud Platform.” Move Over, Meeker: Byron Deeter’s State of the Cloud Report—Bessemer Venture Partners What it’s about:With a nod to Mary Meeker’s classicState of the Internet report,Bessemer Venture Partners’Byron Deeterchecks in with his 2015 State of the Cloud Report. Given cloud computing’s relative youth and rampant ascension, it’s no surprise the stats are staggering. Here’s one to start: Cloud revenues have increased tenfold in the last six years, from a scant $5.6 billion in 2008 to more than $56 billion in 2014. And it’s going to double again in the next four years, according to BVP’s projections, to $127.5 billion in 2018. Why you should care:Deeter’s full presentation is worth a weekend watch or read, but it’s the forward-looking slides that may be most compelling for software pros. Deeter notes both the immense risks and opportunities in cloud security, unveiling a 10-point security plan for cloud startups on slide 37. To underscore the security landscape, Deeter quotes an unnamed cloud CEO who says aDDoSattack that took down the firm’s API caused more customer churn in one day than in the rest of its history. Wow. He also addresses the exploding market for cloud services built specifically for developers including, yes, New Relic. And for mobile developers, slide 44 underscores something we’ve talked about before in this space:the real money’s in enterprise apps, and it’s still a largely untapped market. Click through thefull slide deck hereorwatch video of Deeter’s presentation here. Bandwidth: The Next Frontier of Cloud Computing—ZDnet What it’s about:Is networking the next big thing in the everything-as-a-service age? It just might be, as firms likePacnetvie to deliver networking capacity on a pay-for-what-you-use model that some industry folks say better suits cloud environments facing significant but uneven networking needs. Why you should care:As author Drew Turney notes, there’s a common blind spot when it comes to cloud computing’s many shapes and sizes: Moving all that data from points A to Z, and everywhere in between, which can cause both performance problems and undue financial pressures. The promise of Networking-as-a-Service (NaaS), industry execs tell Turney, is that it can provide more efficient, scalable networking for short-term usage bursts such as customer traffic spikes or large cloud backup-and-storage jobs, enabling companies to later dial down their capacity as needed. Combined withSoftware-Defined Networking (SDN),NaaS makes it possible to build intelligent applications that manage their own networking needs, which might be the most significant enterprise potential of NaaS, saysNuage NetworksarchitectMarten Hauville. Page Bloat: Average Web Page Now More Than 2MB—The Performance Beacon (SOASTA) What it’s about:Do you need to put your website on a diet? Apparently so: The average Web page topped 2 MB as of May 2015, according to ongoing tracking atThe Performance Beacon. That’s double the average page weight from just three years ago. The site projects average page weight will exceed 3 MB in late 2017. Why you should care:Performance, performance, performance:Slow speedsare a killerin the modern software era. While author andSOASTAUX evangelistTammy Evertsrightly notes that page weight is not the only factor in Web optimization, we’re simply not paying it enough attention when designing and building Web pages. Images are the big culprit in the Web’s expanding waistline: they comprise nearly two-thirds of the average page’s weight, and video is a growing part of our Web diet, too. But other factors such as custom fonts play a role, adding weight even as the Web sheds previous performance hogs like Flash. The ideal weight? 1 MB, she says, which will save crucial seconds in load times. Sounds like it’s time to hit the virtual treadmill.

Learn why 12 Factor Application Patterns, Microservices and CloudFoundry matter when trying to change the way your product is produced.

hadoop is best known for map reduce and it's distributed file system (hdfs). recently other productivity tools developed on top of these will form a complete ecosystem of hadoop. most of the projects are hosted under apache software foundation . hadoop ecosystem projects are listed below. hadoop common a set of components and interfaces for distributed file system and i/o (serialization, java rpc, persistent data structures) http://hadoop.apache.org/ hadoop ecosystem hdfs a distributed file system that runs on large clusters of commodity hardware. hadoop distributed file system, hdfs renamed form ndfs. scalable data store that stores semi-structured, un-structured and structured data. http://hadoop.apache.org/docs/r2.3.0/hadoop-project-dist/hadoop-hdfs/hdfsuserguide.html http://wiki.apache.org/hadoop/hdfs map reduce map reduce is the distributed, parallel computing programming model for hadoop. inspired from google map reduce research paper . hadoop includes implementation of map reduce programming model. in map reduce there are two phases, not surprisingly map and reduce. to be precise in between map and reduce phase, there is another phase called sort and shuffle. job tracker in name node machine manages other cluster nodes. map reduce programming can be written in java. if you like sql or other non- java languages, you are still in luck. you can use utility called hadoop streaming. http://wiki.apache.org/hadoop/hadoopmapreduce hadoop streaming a utility to enable map reduce code in many languages like c, perl, python, c++, bash etc., examples include a python mapper and awk reducer. http://hadoop.apache.org/docs/r1.2.1/streaming.html avro a serialization system for efficient, cross-language rpc and persistent data storage. avro is a framework for performing remote procedure calls and data serialization. in the context of hadoop, it can be used to pass data from one program or language to another, e.g. from c to pig. it is particularly suited for use with scripting languages such as pig, because data is always stored with its schema in avro. http://avro.apache.org/ apache thrift apache thrift allows you to define data types and service interfaces in a simple definition file. taking that file as input, the compiler generates code to be used to easily build rpc clients and servers that communicate seamlessly across programming languages. instead of writing a load of boilerplate code to serialize and transport your objects and invoke remote methods, you can get right down to business. http://thrift.apache.org/ hive and hue if you like sql, you would be delighted to hear that you can write sql and hive convert it to a map reduce job. but, you don't get a full ansi-sql environment. hue gives you a browser based graphical interface to do your hive work. hue features a file browser for hdfs, a job browser for map reduce/yarn, an hbase browser, query editors for hive, pig, cloudera impala and sqoop2.it also ships with an oozie application for creating and monitoring workflows, a zookeeper browser and an sdk. pig a high-level programming data flow language and execution environment to do map reduce coding the pig language is called pig latin. you may find naming conventions some what un-conventional, but you get incredible price-performance and high availability. https://pig.apache.org/ jaql jaql is a functional, declarative programming language designed especially for working with large volumes of structured, semi-structured and unstructured data. as its name implies, a primary use of jaql is to handle data stored as json documents, but jaql can work on various types of data. for example, it can support xml, comma-separated values (csv) data and flat files. a "sql within jaql" capability lets programmers work with structured sql data while employing a json data model that's less restrictive than its structured query language counterparts. 1. jaql in google code 2. what is jaql? by ibm sqoop sqoop provides a bi-directional data transfer between hadoop -hdfs and your favorite relational database. for example you might be storing your app data in relational store such as oracle, now you want to scale your application with hadoop so you can migrate oracle database data to hadoop hdfs using sqoop. http://sqoop.apache.org/ oozie manages hadoop workflow. this doesn't replace your scheduler or BPM tooling, but it will provide if-then-else branching and control with hadoop jobs. https://oozie.apache.org/ zookeeper a distributed, highly available coordination service. zookeeper provides primitives such as distributed locks that can be used for building the highly scalable applications. it is used to manage synchronization for cluster. http://zookeeper.apache.org/ hbase based on google's bigtable , hbase "is an open-source, distributed, version, column-oriented store" that sits on top of hdfs. a super scalable key-value store. it works very much like a persistent hash-map (for python developers think like a dictionary). it is not a conventional relational database. it is a distributed, column oriented database. hbase uses hdfs for it's underlying. supports both batch-style computations using map reduce and point queries for random reads. https://hbase.apache.org/ cassandra a column oriented nosql data store which offers scalability, high availability with out compromising on performance. it perfect platform for commodity hardware and cloud infrastructure.cassandra's data model offers the convenience of column indexes with the performance of log-structured updates, strong support for de-normalization and materialized views , and powerful built-in caching. http://cassandra.apache.org/ flume a real time loader for streaming your data into hadoop. it stores data in hdfs and hbase.flume "channels" data between "sources" and "sinks" and its data harvesting can either be scheduled or event-driven. possible sources for flume include avro, files, and system logs, and possible sinks include hdfs and hbase. http://flume.apache.org/ mahout machine learning for hadoop, used for predictive analytics and other advanced analysis. there are currently four main groups of algorithms in mahout: recommendations, a.k.a. collective filtering classification, a.k.a categorization clustering frequent item set mining, a.k.a parallel frequent pattern mining mahout is not simply a collection of pre-existing algorithms; many machine learning algorithms are intrinsically non-scalable; that is, given the types of operations they perform, they cannot be executed as a set of parallel processes. algorithms in the mahout library belong to the subset that can be executed in a distributed fashion. http://en.wikipedia.org/wiki/list_of_machine_learning_algorithms https://www.coursera.org/course/machlearning https://mahout.apache.org/ fuse makes the hdfs system to look like a regular file system so that you can use ls, rm, cd etc., directly on hdfs data. whirr apache whirr is a set of libraries for running cloud services. whirr provides a cloud-neutral way to run services. you don't have to worry about the idiosyncrasies of each provider.a common service api. the details of provisioning are particular to the service. smart defaults for services. you can get a properly configured system running quickly, while still being able to override settings as needed. you can also use whirr as a command line tool for deploying clusters. https://whirr.apache.org/ giraph an open source graph processing api like pregel from google https://giraph.apache.org/ chukwa chukwa, an incubator project on apache, is a data collection and analysis system built on top of hdfs and map reduce. tailored for collecting logs and other data from distributed monitoring systems, chukwa provides a workflow that allows for incremental data collection, processing and storage in hadoop. it is included in the apache hadoop distribution as an independent module. https://chukwa.apache.org/ drill apache drill, an incubator project on apache, is an open-source software framework that supports data-intensive distributed applications for interactive analysis of large-scale datasets. drill is the open source version of google's dremel system which is available as an iaas service called google big query. one explicitly stated design goal is that drill is able to scale to 10,000 servers or more and to be able to process petabytes of data and trillions of records in seconds. http://incubator.apache.org/drill/ impala (cloudera) released by cloudera, impala is an open-source project which, like apache drill, was inspired by google's paper on dremel; the purpose of both is to facilitate real-time querying of data in hdfs or hbase. impala uses an sql-like language that, though similar to hiveql, is currently more limited than hiveql. because impala relies on the hive meta store, hive must be installed on a cluster in order for impala to work. the secret behind impala's speed is that it "circumvents map reduce to directly access the data through a specialized distributed query engine that is very similar to those found in commercial parallel rdbmss." (source: cloudera) http://www.cloudera.com/content/cloudera/en/products-and-services/cdh/impala.html http://training.cloudera.com/elearning/impala/

Efficient open source event counters from the Agrona library. Agrona The Agrona library is an open source Java library of utility code. Unlike libraries such as Google Guava or Apache Commons which are general purpose Java utility libraries, Agrona is targeted at providing high performance code. It initially consists of code from the open source Aeron messaging library. Event Counters One of the features of the Agrona library is the event counters framework. One of the design goals of Aeron was to be easy to monitor. We wanted to make sure that people could easily check up on what Aeron is doing with services such as Nagios, internally written monitoring software or just from the commandline. Writing integrations with many services is a herculean task in and of itself, but we definitely wanted to be able to expose an API. We also didn't want to incorporate large 3rd party external dependencies, any allocation heavy code or things we couldn't control the performance of. This meant that we were going to have to write our own event counters rather than using something like the Coda Hale metrics framework. Our requirements for monitoring were very simple though. Update or increment the counter's value. Read or write to/from the counter value from a different thread or process. No garbage creation after initial setup. Labels should be associated with each counter value for readability's sake. Design Threadsafe updates of a long value is a very simple operation and already supported in Java through the AtomicLong class. The problem with using an AtomicLong as your event counter is that an external program, running in a different process, can't read from the value from your Java heap. Consequently Agrona's event counters are allocated in an off-heap buffer. This can be placed on a memory-mapped file which means it can be shared between two different processes. In order to give our counters names we store a table of name and counter id entries on another buffer. This can be placed on the same memory mapped file for convenience. API The CountersManager is responsible for allocating event counters. It needs to be instantiated with the buffers upon which to store the event counters and their labels. Here is an example of how to instantiate a counter from the counters manager. AtomicCounter conductorProxyFails = countersManager.newCounter("Failed offers to DriverConductorProxy"); You can also iterate over the current counter names and their ids. Here is some code that uses that to print a table of the event counter values: countersManager.forEach((id, label)->{finalint offset =CountersManager.counterOffset(id);finallong value = valuesBuffer.getLongVolatile(offset);System.out.format("%3d: %,20d - %s\n", id, value, label);}); Each instance of AtomicCounter represents one event counter. Here are some examples of using the atomic counter in code. // Increment the counter in a thread-safe manner conductorProxyFails.increment();// Increment the counter if you're only writing from a single thread conductorProxyFails.orderedIncrement();// atomically add 5 to the counter value conductorProxyFails.add(5);// Reset the counter conductorProxyFails.set(0); Conclusions I've just gone through a few simple examples of how to use the event counters from Agrona, which hopefully you've found useful. This isn't the only code in Agrona though - there are utilities for agents, and executing timing events as well as collections such as queues, ringbuffers and hashmaps. We're also expanding the library which is already on maven central. Currently documentation is a little bit thin on the ground, but contributions are always welcome. Thanks to Martin Thompson and Chris West for feedback on this blog post.

Parse your Java stack trace log information with the Logstash tool.

When I talk with customers about sharding decisions I often start by telling the following true story… A couple of years ago, a customer came to me looking for advice on how to shard his system. He told me he was already convinced he needed to do that since he read that some smart people at MySQL giants like Facebook and Twitter were sharding—so naturally this was something he should be doing, too. I paused for a moment and then I asked him what the size of his database was. “10GB,” he said. I nodded and asked if he handles many queries or if they were very complicated. “No,” he said. “Just a few hundred queries per second, and they have not been loading down the system by more than a few percent.” I asked him whether he was expecting exponential growth in the near future—looking to double every week or something like that. “No, our load and data size grew about 7 percent last year and we expect about the same growth this year and for the foreseeable future.” My recommendation to him was not to waste time and effort on sharding because it is just not needed in his company’s case. Before you decide how to shard, you’d best understand whether or not you really need to shard to begin with. Yes, on the extremely large-scale side of database demands, sharding is the only game in town. And not just for MySQL, but for pretty much any technology out there. Yet thanks to emerging technologies there is an increasing amount of applications that can run databases without sharding. Today we can easily run with terabytes of data per MySQL instance and serve tens of thousands of queries in many OLTP environments. This allows organizations to build very large applications without needing to shard. And keep this in mind: Sharding is a pain under all circumstances. Even if you have sharding provided out of the box by the database system, it is a pain because it introduces more components and complexity. Creating good distributed query execution plans is a very complicated task that needs to take network topology and load into account in addition to the data distribution and load of individual nodes. Before you decide if you need to shard, you should look at alternatives to scale your application. In the MySQL world, the solutions are typically as follows: Alternatives to Sharding Functional Partitioning: In many environments a single MySQL instance becomes a dumping ground for all kinds of databases—you might end up having your main application share a database instance with Drupal, which powers your website, with WordPress, which powers your blog, and with vBulletin, which powers your forums. Splitting those pieces into different database instances is something you should consider before you look into sharding. Custom-made systems will often have many applications using different data sets that can be easily split out. Replication: Many applications are read-heavy, so scaling reads becomes the issue earlier than it does with scaling writes. Replication is a great solution for this. MySQL’s built-in replication is very robust, though due to its asynchronous nature it adds complexity to the application. The developer must decide which of the reads can be done from the replica servers and which can’t, because you must be absolutely certain that you’re reading the most recent, actual data. This is the reason that alternative, synchronous replication technologies for MySQL like Percona XtraDB Cluster, are gaining popularity: They provide single database-like behavior from the cluster in most cases. Caching and Queueing: Caching is a great technology for reducing the amount of reads that hit the database. There are many applications that have reduced read load on the database by 80-95% using this technology. Queueing, in contrast, optimizes writes. It does this by merging multiple write operations together so they hit the database efficiently. Most large-scale applications should rely heavily on both of these technologies. Memcached and Redis are two popular caching technologies in the MySQL space. For queueing, the most popular technologies are ActiveMQ and RabbitMQ [1]. Supplemental Technologies: MySQL is great at many things but not at everything. If you’re looking for high-performance full-text search, consider ElasticSearch, Sphinx, or Lucene. If you’re looking at large-scale data analytics, a Hadoop-based infrastructure or Vertica might work well for you. You should let MySQL handle the things it is good at, and leave the rest to supporting tools. Optimizations to Make Before Sharding Scaling isn’t just about architecture either. You also need to make sure your system is reasonably optimized. Many people decide sharding is inevitable for them even though there are much easier and more cost-effective ways to get the performance and scale they are looking for. All of which, I might add, are also going to be valuable if sharding is indeed eventually needed. Hardware: Are you using the right hardware? I’ve seen many people looking into sharding when in fact simply purchasing decent hardware would solve their problems for years to come. Make sure you have plenty of memory and high-performance flash storage if you’re working with a large database. In many cases it can transform your system so much it will look like magic. MySQL version and Configuration: Use a recent MySQL version. By that I mean the latest GA version (MySQL 5.6 at the time of this article’s publication). Percona Server, which is free, often offers additional performance improvements for demanding workloads. Use the most recent operating system too, especially if you’re using modern hardware. Finally, make sure MySQL is configured properly. The difference in MySQL performance between poorly configured MySQL and well-tuned MySQL can be 10x or more. Schema and Queries: The same application logic can be expressed using a variety of schema and queries. I’ve seen a lot of similar applications approaching things differently, and the difference in the performance between an optimal approach and a poor one (but still used in production) can be 100x or more. Many of the changes can be retrofitted to existing schema—such as minor query changes and changes to the index structure—however, if your schema doesn’t fit your application needs well, then you might be looking at a complete redesign. So it is a good idea to think things through early. When to Shard So when should you start thinking about sharding? Basically, if none of the measures listed above have given you the performance you need, it might be time to consider sharding. Sharding does have the advantage of allowing you to potentially use lower-cost hardware or cheaper cloud instances. Most developers are using agile development methods these days and there is a common term, “Architectural Runway,” which defines how far the application can go with its current architecture. If you’ve already found success using replication in particular, it might be a bad decision to add sharding because it will force your developers to deal with the complexity of sharding and asynchronous replication. However, replication is still typically used to achieve high availability even if you’re already sharding, but in this case it’s not for scaling reads. If you’ve come to the point where you’re sure you need to shard, here are some of the questions you need to ask about how you’ll implement your sharding strategy: Shard Level: At which level should we shard? It does not have to be at the database level. Many applications, SaaS in particular, often “shard” on higher levels, deploying multiple copies of their full stack to offer complete isolation for availability, performance, security etc. In many large scale applications you will see multiple copies of a full stack deployed, each having its own sharded MySQL environment. Shard Key: How do we shard? In many cases the choice depends on whether you’re authenticating for user accounts or your organization, but in other cases it is not so obvious. When making a sharding choice, you need to think about two things: 1) as many data access points as possible should go into a single shard, because cross-shard access is expensive if supported at all, and 2) making sure such sharding does not produce a shard that is too large to handle either in terms of data size or traffic. For example, sharding by country is a poor idea because the requirements to handle Belgium traffic won’t be the same for the United States or China, which require a lot more resources. Shard by Schema or Instance: What is the unit of your shard? The typical choices are MySQL instance or database (schema). I like the shard = database approach, which doesn’t limit you to a single MySQL instance per physical box. That way you do not have to run too many MySQL instances, but you can run more than one if the application works better that way. Shard Unit: If you shard by a single MySQL server, you will run into a problem with high availability very soon. When you have 100 MySQL servers there are roughly 100 more chances for one of them to crash compared with having only one, so ensuring there is a high availability solution becomes critical. Instead of sharing across MySQL servers you will usually be sharding across “Replication Clusters,” such as one MySQL primary node and one or several replica or PXC (Percona XtraDB Cluster) nodes. Shard Technology: What technology can you use to assist you with sharding? Within the MySQL world there is no standard sharding technology as of yet that everyone uses. Most of the large web properties have implemented something in-house for their sharding needs, and some have released their solutions as open source projects. One example is Vitess, contributed by Google, and another is JetPants, contributed by Tumblr. Rolling out your own simple sharding framework might look easy for some developers until you have to deal with operational issues like balancing the shards, resharding, etc., on a large scale. There are a number of purpose-built technologies that can help you with sharding if this doesn’t sound like something your team can manage. Sharding Technologies Here are technologies that you should consider: MySQL Fabric: This is the sharding technology being developed by the MySQL team at Oracle. MySQL Fabric is GA, but its functionality right now is rather limited, especially in terms of their support for multi-sharded queries. Given more time however, it has the potential to become the standard sharding technology for MySQL. Tesora: Tesora has a proxy-based solution for MySQL sharding that became open source some time ago. I would be especially looking at Tesora if you’re also looking at deploying OpenStack, as they’ve invested a lot into the integration. ScaleArc: ScaleArc is a commercial database proxy solution that can do caching, filtering, routing, and sharding. It is a pretty mature solution that handles multiple database technologies and not just MySQL. ScaleBase: ScaleBase is a sharding solution designed specifically for MySQL and the cloud, which similarly to MySQL, operates at the proxy level. There are many technologies in the MySQL space that can help you scale your application without sharding. If you’re going to build the next “Facebook,” however, you will surely need to shard, and there are a number of technologies that can help you do it as painlessly as possible. Large-scale applications on large-scale databases will always introduce complexity, which makes them more complicated to develop against and manage. Success comes with cost. [1] http://dzone.com/research/guide-to-enterprise-integration Peter Zaitsev co-founded Percona in 2006, assuming the role of CEO. Percona helps companies of all sizes maximize their success with MySQL. Peter enjoys mixing business leadership with hands on technical expertise. Peter is also the co-author of O’Reilly’s High Performance MySQL, one of the most popular books on MySQL performance.

Authors of PVS-Studio static code analyzers offer programmers to test their sight and to try finding errors in C/C++ code fragments. Code analyzers work tirelessly and are able to find many bugs that can be difficult to notice. We chose some code fragments in which we had founded some errors using PVS-Studio. Quiz is not intended to check C++ language knowledge. There are many quality and interesting tests. For instance, we would recommend this C++ Quiz then. In our case, we made our test just for fun. We quite frequently hear an opinion that code analyzers are pointless tools. It is possible to find misplaced parenthesis or comma in five seconds. However, analyzer would not find difficult logical errors. Therefore, this tool could be useful only for students. We decided to troll these people. There is a time limit in tests. We ask them to find an error in five seconds. Well, OK, not in five seconds, but in a minute. Fifteen randomly selected problems would be shown. Every solved problem worth one point, but only if user provided the answer in one minute. We want to stress that we are not talking about syntax errors. We found all these code fragments in open-source projects that compiles flawlessly. Let us explain on a pair of examples how to point out the correct answer. First example. For instance, you got this code: The bug here is highlighted with red color. Of course, there would be no such emphasizing in a quiz problem. Programmer accidently made a misprint and wrote index 3 instead of index 2. Mouse cursor movement would highlight fragments of code, such as words and numbers. You should point the cursor into number 3 and press left mouse button. This would be the correct answer. Second example. It is not always possible to point out the error exactly. Buffer size should be compared with number 48. An excess sizeof() operator was put there by accident. In result, buffer size is compared with size of int type. At my opinion, an error there is in sizeof operator, and it is required to point it out to score a correct answer. However, without knowledge about the whole text, it is possible to think this way. Sizeof operator should have evaluated the size of some buffer, but accidently evaluates the value of the macro. The error is in “SSL3_MASTER_SECRET_LENGTH” usage. In this case, the answer will be scored no matter what you choose: “sizeof” or “SSL3_MASTER_SECRET_LENGTH”. Good luck! You can start a game. Footnote. Test does not support mobile devices. It is very easy to miss with finger. We are working on new version of tests with better mobile devices support, new problems to solve etc. However, it is not implemented yet. We offer you to subscribe on twitter to read about our new and interesting news and to read about new things in a C++ world.

Raygun, Stack Hunter, Sentry, Takipi and Airbrake: Modern developer tools to help you crush bugs before bugs crush your app With the Java ecosystem going forward, web applications serving growing numbers of requests and users’ demand for high performance - comes a new breed of modern development tools. A fast paced environment with rapid new deployments requires tracking errors and gaining insight to an application's behavior on a level traditional methods can’t sustain. In this post we’ve decided to gather 5 of those tools, see how they integrate with Java and find out what kind of tricks they have up their sleeves. It’s time to smash some bugs. Raygun Mindscape’s Raygun is a web based error management system that keeps track of exceptions coming from your apps. It supports various desktop, mobile and web programming languages, including Java, Scala, .NET, Python, PHP, and JavaScript. Besides that, sending errors to Raygun is possible through a REST API and a few more Providers (that’s how they call language and framework integrations) came to life thanks to developer community involvement. Key Features: Error grouping - Every occurrence of a bug is presented within one group with access to single instances of it, including its stack trace. Full text search - Error groups and all collected data is searchable. View app activity - Every action on an error group is displayed for all your team to see: status updates, comments and more. Affected users - Counts of affected users appear by each error. External integrations - Github, Bitbucket, Asana, JIRA, HipChat and many more. The Java angle: To use Raygun with Java, you’ll need to add some dependencies to your pom.xml file if you’re using Maven or add the jars manually. The second step would be to add an UncaughtExceptionHandler that would create an instance of RaygunClient and send your exceptions to it. In addition, you can also add custom data fields to your exceptions and send them together to Raygun. The full walkthrough is available here. Behind the curtain: Meet Robie Robot, the certified operator of Raygun. As in, the actual ray gun. Check it out on: https://raygun.io Sentry Started as a side-project, Sentry is an open-source web based solution that serves as a real time event logging and aggregation platform. It monitors errors and displays when, where and to whom they happen, promising to do so without relying solely on user feedback. Supported languages and frameworks include Ruby, Python, JS, Java, Django, iOS, .NET and more. Key Features: See the impact of new deployments in real time Provide support to specific users interrupted by an error Detect and thwart fraud as its attempted - notifications of unusual amounts of failures on purchases, authentication, and other sensitive areas External Integrations - GitHub, HipChat, Heroku, and many more The Java angle: Sentry’s Java client is called Raven and supports major existing logging frameworks like java.util.logging, Log4j, Log4j2 and Logback with Slf4j. An independent method to send events directly to Sentry is also available. To set up Sentry for Java with Logback for example, you’ll need to add the dependencies manually or through Maven, then add a new Sentry appender configuration and you’re good to do. Instructions are available here. Behind the curtain: Sentry was an internal project at Disqus back in 2010 to solve exception logging on a Django application by Chris Jennings and David Cramer Check it out on: https://www.getsentry.com/ Takipi Unlike most of the other tools, Takipi is far more than a stack trace prettifier. It was built with a simple objective in mind: Telling developers exactly when and why production code breaks. Whenever a new exception is thrown or a log error occurs – Takipi captures it and shows you the variable state which caused it, across methods and machines. Takipi will overlay this over the actual code which executed at the moment of error – so you can analyze the exception as if you were there when it happened. Key features: Detect – Caught/uncaught exceptions, Http and logged errors. Prioritize – How often errors happen across your cluster, if they involve new or modified code, and whether that rate is increasing. Analyze – See the actual code and variable state, even across different machines and applications. Easy to install - No code or configuration changes needed. Less than 2% overhead. The Java angle: Takipi was built for production environments in Java and Scala. The installation takes less than 1min, and includes attaching a Java agent to your JVM. Behind the curtain: Each exception type and error has a unique monster that represents it. You can find these monster here. Check it out on: http://www.takipi.com/ Airbrake Another tool that has put exception tracking on its eyesights is Rackspace’s Airbrake, taking on the mission of “No More Searching Log Files”. It provides users with a web based interface that includes a dashboard with error details and an application specific view. Supported languages include Ruby, PHP, Java, .NET, Python and even… Swift. Key Features: Detailed stack traces, grouping by error type, users and environment variables Team productivity - Filter importance errors from the noise Team collaboration - See who’s causing bugs and whose fixing them External Integrations - HipChat, GitHub, JIRA, Pivotal and over 30 more The Java angle: Airbrake officially supports only Log4j, although a Logback library is also available. Log4j2 support is currently lacking. The installation procedure is similar to Sentry, adding a few dependencies manually or through Maven, adding an appender, and you’re ready to start. Similarly, a direct way to send messages to Airbrake is also available with AirbrakeNotice and AirbrakeNotifier. More details are available here. Behind the curtain: Airbrake was acquired by Exceptional, which then got acquired by Rackspace. Check it out on: https://airbrake.io/ StackHunter Currently in beta, Stack Hunter provides a self hosted tool to track your Java exceptions. A change of scenery from the past hosted tools. Other than that, it aims to provide a similar feature set to inform developers of their exceptions and help solve them faster. Key Features: A single self hosted web interface to view all exceptions Collections of stack trace data and context including key metrics such as total exceptions, unique exceptions, users affected, & sessions affected Instant email alerts when exceptions occur Exceptions grouping by root cause The Java angle: Built specifically for Java, StackHunter runs on any servlet container running Java 6 or above. Installation includes running StackHunter on a local servlet, configuring an outgoing mail server for alerts, and configuring the application you’re wishing to log. Full instructions are available here. Behind the curtain: StackHunter is developed by Dele Taylor, who also works on Data Pipeline - a tool for transforming and migrating data in Java. Check it out on: http://stackhunter.com/ Bonus: ABRT Another approach to error tracking worth mentioning is used by ABRT, an automatic bug detection and reporting tool from the Fedora ecosystem, which is a Red Hat sponsored community project. Unlike the 5 tools we covered here, this one is intended to be used not only by app developers - but their users as well. Reporting bugs back to Red Hat with richer context that otherwise would have been harder to understand and debug. The Java angle: Support for Java exceptions is still in its proof of concept stage. A Java connector developed by Jakub Filák is available here. Behind the curtain: ABRT is an open-source project developed by Red Hat. Check it out on: https://github.com/abrt/abrt Did we miss any other tools? How do you keep track of your exceptions? Please let me know in the comments section below.

Some of the hardest problems a Java Developer will ever have to face are classpath errors: ClassNotFoundException, NoClassDefFoundError, Jar Hell, Xerces Hell and company. In this post we will go through the root causes of these problems, and see how a minimal tool (JHades) can help solving them quickly. We will see why Maven cannot (always) prevent classpath duplicates, and also: The only way to deal with Jar Hell Class loaders The Class loader chain Class loader priority: Parent First vs Parent Last Debugging server startup problems Making sense of Jar Hell with jHades Simple strategy for avoiding classpath problems The classpath gets fixed in Java 9? The only way to deal with Jar Hell Classpath problems can be time-consuming to debug, and tend to happen at the worst possible times and places: before releases, and often in environments where there is little to no access by the development team. They can also happen at the IDE level, and become a source of reduced productivity. We developers tend to find these problems early and often, and this is the usual response: Let's try to save us some hair and get to the bottom of this. These type of problems are hard to approach via trial and error. The only real way to solve them is to really understand what is going on, but where to start? It turns out that Jar Hell problems are simpler than what they look, and only a few concepts are needed to solve them. In the end, the common root causes for Jar Hell problems are: a Jar is missing there is one Jar too many a class is not visible where it should be But if it's that simple, then why are classpath problems so hard to debug? Jar Hell stack traces are incomplete One reason is that the stack traces for classpath problems have a lot of information missing that is needed to troubleshoot the problem. Take for example this stack trace: java.lang.IncompatibleClassChangeError: Class org.jhades.SomeServiceImpl does not implement the requested interfaceorg.jhades.SomeService org.jhades.TestServlet.doGet(TestServlet.java:19) It says that a class does not implement a certain interface. But if we look at the class source: publicclassSomeServiceImpl implementsSomeService { @Override publicvoiddoSomething() { System.out.println( "Call successful!"); } Well, the class clearly implements the missing interface! So what is going on then? The problem is that the stack trace is missing a lot of information that is critical to understanding the problem. The stack trace should have probably contained an error message such as this (we will learn what this means): The Class SomeServiceImpl of class loader /path/to/tomcat/lib does not implement the interface SomeService loaded from class loader Tomcat - WebApp - /path/to/tomcat/webapps/test This would be at least an indication of where to start: Someone new learning Java would at least know that there is this notion of class loader that is essential to understand what is going on It would make clear that one class involved was not being loaded from a WAR, but somehow from some directory on the server (SomeServiceImpl). What is a Class Loader? To start, a Class Loader is just a Java class, more exactly an instance of a class at runtime. It is NOT an inaccessible internal component of the JVM like for example the garbage collector. Take for example the WebAppClassLoader of Tomcat, here is it's javadoc. As you can see it's just a plain Java class, we can even write our own class loader if needed. Any subclass of ClassLoader will qualify as a class loader. The main responsibilities of a class loader is to known where class files are located, and then load classes on JVM demand. Everything is linked to a class loader Each object in the JVM is linked to it's Class via getClass(), and each class is linked to a class loader via getClassLoader(). This means that: Every object in the JVM is linked to a class loader! Let's see how this fact can be used to troubleshoot a classpath error scenario. How-To find where a class file really is Let's take an object and see where it's class file is located in the file system: System.out.println(service.getClass() .getClassLoader() .getResource("org/jhades/SomeServiceImpl.class")); This is the full path to the class file: jar:file:/Users/user1/.m2/repository/org/jhades/jar-2/1.0-SNAPSHOT/jar-2-1.0-SNAPSHOT.jar!/org/jhades/SomeServiceImpl.class As we can see the class loader is just a runtime component that knowns where in the file system to look for class files and how to load them. But what happens if the class loader cannot find a given class? The Class loader Chain By default in the JVM, if a class loader does not find a class, it will then ask it's parent class loader for that same class and so forth. This continues all the way up until the JVM bootstrap class loader (more on this later). This chain of class loaders is the class loader delegation chain. Class loader priority: Parent First vs Parent Last Some class loaders delegate requests immediately to the parent class loader, without searching first in their own known set of directories for the class file. A class loader operating on this mode is said to be in Parent First mode. If a class loader first looks for a class locally and only after queries the parent if the class is not found, then that class loader is said to be working in Parent Last mode. Do all applications have a class loader chain ? Even the most simple Hello World main method has 3 class loaders: The Application class loader, responsible for loading the application classes (parent first) The Extensions class loader, that loads jars from $JAVA_HOME/jre/lib/ext (parent first) The Bootstrap class loader, that loads any class shipped with the JDK such as java.lang.String (no parent class loader) What does the class loader chain of a WAR application look like? In the case of application servers like Tomcat or Websphere, the class loader chain is configured differently than a simple Hello World main method program. Take for example the case of the Tomcat class loader chain: Here we wee that each WAR runs in a WebAppClassLoader, that works in parent last mode (it can be set to parent first as well). The Common class loader loads libraries installed at the level of the server. What does the Servlet spec say about class loading? Only a small part of the class loader chain behavior is defined by the Servlet container specification: The WAR application runs on it's own application class loader, that might be shared with other applications or not The files in WEB-INF/classes take precedence over everything else After that, it's anyones guess! The rest is completely open for interpretation by container providers. Why isn't there a common approach for class loading across vendors? Usually open source containers like Tomcat or Jetty are configured by default to look for classes in the WAR first, and only then search in server class loaders. This allows for applications to use their own versions of libraries that override the ones available on the server. What about the big iron servers? Commercial products like Websphere will try to 'sell' you their own server provided libraries, that by default take precedence over the ones installed on the WAR. This is done assuming that if you bought the server you want also to use the JEE libraries and versions it provides, which is often NOT the case. This makes deploying to certain commercial products a huge hassle, as they behave differently then the Tomcat or Jetty that developers use to run applications in their workstation. We will see further on a solution for this. Common Problem: duplicate class versions At this moment you probably have a huge question: What if there are two jars inside a WAR that contain the exact same class? The answer is that the behavior is undetermined and only at runtime one of the two classes will be chosen. Which one gets chosen depends on the internal implementation of the class loader, there is no way to know upfront. But luckily most projects these days use Maven, and Maven solves this problem by ensuring only one version of a given jar is added to the WAR. So a Maven project is immune to this particular type of Jar Hell, right? Why Maven does not prevent classpath duplicates Unfortunately Maven cannot help in all Jar Hell situations. In fact, many Maven projects that don't use certain quality control plugins can have hundreds of duplicate class files on the classpath (I saw trunks with over 500 duplicates). There are several reasons for that: Library publishers occasionally change the artifact name of a jar: This happens due to re-branding or other reasons. Take for example the example of the JAXB jar. There is no way Maven can identify those artifacts as being the same jar! Some jars are published with and without dependencies: Some library providers provide a 'with dependencies' version of a jar, which includes other jars inside. If we have transitive dependencies with the two versions, we will end up with duplicates. Some classes are copied between jars: Some library creators, when faced with the need for a certain class will just grab it from another project and copy it to a new jar without changing the package name. Are all class files duplicates dangerous? If the duplicate class files exist inside the same class loader, and the two duplicate class files are exactly identical then it does not matter which one gets chosen first - this situation is not dangerous. If the two class files are inside the same class loader and they are not identical, then there is no way which one will be chosen at runtime - this is problematic and can manifest itself when deploying to different environments. If the class files are in two different class loaders, then they are never considered identical (see the class identity crisis section further on). How can WAR classpath duplicates be avoided? This problem can be avoided for example by using the Maven Enforcer Plugin, with the extra rule of Ban Duplicate Classes turned on. You can quickly check if your WAR is clean using the JHades WAR duplicate classes report as well. This tool has an option to filter 'harmless' duplicates (same class file size). But even a clean WAR might have deployment problems: Classes missing, classes taken from the server instead of the WAR and thus with the wrong version, class cast exceptions, etc. Debugging the classpath with JHades Classpath problems often show up when the application server is starting up, which is a particularly bad moment specially when deploying to an environment where there is limited access. JHades is a tool to help deal it with Jar Hell (disclaimer: I wrote it). It's a single Jar with no dependencies other than the JDK7 itself. This is an example of how to use it: newJHades() .printClassLoaders() .printClasspath() .overlappingJarsReport() .multipleClassVersionsReport() .findClassByName("org.jhades.SomeServiceImpl") This prints to the screen the class loader chain, jars, duplicate classes, etc. Debugging server startup problems JHades works works well in scenarios where the server does not start properly. A servlet listener is provided that allows to print classpath debugging information even before any other component of the application starts running. ClassCastException and the Class Identity Crisis When troubleshooting Jar Hell, beware of ClassCastExceptions. A class is identified in the JVM not only by it's fully qualified class name, but also by it's class loader. This is counterintuitive but in hindsight makes sense: We can create two different classes with the same package and name, ship them in two jars and put them in two different class loaders. One let's say extends ArrayList and the other is a Map. The classes are therefore completely different (despite the same name) and cannot be cast to each other! The runtime will throw a CCE to prevent this potential error case, because there is no guarantee that the classes are castable. Adding the class loader to the class identifier was the outcome of the Class Identity Crisis that occurred in earlier Java days. A Strategy for Avoiding Classpath Problems This is easier said then done, but the best way to avoid classpath related deployment problems is to run the production server in Parent Last mode. This way the class versions of the WAR take precedence over the ones on the server, and the same classes are used in production and in a developer workstation where it's likely that Tomcat, Jetty or other open source Parent Last server is being used. In certain servers like Websphere, this is not sufficient and you also have to provide special properties on the manifest file to explicitly turn off certain libraries like for example JAX-WS. Fixing the classpath in Java 9 In Java 9 the classpath gets completely revamped with the new Jigsaw modularity system. In Java 9 a jar can be declared as a module and it will run in it's own isolated class loader, that reads class files from other similar module class loaders in an OSGI sort of way. This will allow multiple versions of the same Jar to coexist in the same application if needed. Conclusions In the end, Jar Hell problems are not that low level or unapproachable as they might seem at first. It's all about zip files (jars) being present/ not being present in certain directories, how to find those directories, and how to debug the classpath in environments with limited access. By knowing a limited set of concepts such as Class Loaders, the Class Loader Chain and Parent First / Parent Last modes, these problems can be tackled effectively. External links This presentation Do you really get class loaders from Jevgeni Kabanov of ZeroTurnaround (JRebel company) is a great resource about Jar Hell and the different type of classpath related exceptions.

Ode To Code - Easily Generate Microsoft Office Files From C# "... These days, Office files are no longer in a proprietary binary format, and are we can create the files directly without using COM automation. A .docx Word file, for example, is a collection of XML documents zipped into a single file. The official name of the format is Open XML. There is an SDK to help with reading and writing OpenXML, and a Productivity Tool that can generate C# code for a given file. All you need to do is load a document, presentation, or workbook into the tool and press the “Reflect Code” button. The downside to this tool is that even a simple document will generate 4,000 lines of code. Another downside is that the generated code assumes it will write directly to the file system, however it is easy to pass in an abstract Stream object instead. So while this code isn’t perfect, the code does produce valid document and..." I've been blogging about the OpenXML SDK for years now, but I think this is the first time I've seen this part of it, this utility. And like he says, 4K LoC is like, well, allot, it does look like an awesome way to learn the low level OpenXML SDK ins and outs. Related Past Post XRef: Open Sesame - Open XML SDK is now open source Using OpenXML to load an Excel Worksheet into a DataTable (or just how different OpenXML is from the old Excel API we're used too) Using OpenXML SDK to generate Word documents via templates (and without Word being installed) Checking for Microsoft Word DocX/DocM Revisions/Track Changes without using Word... (via OpenXML SDK, LINQ to XML or XML DOM) LINQ to XlsX... Using VB.Net, LINQ, the OpenXML SDK and a little C# helper, to query an Excel XlsX Using native OpenXML to create an XlsX (Which provides an example of why I highlight tools that make OpenXML easier...) Generating Xlsx's on the Server? You're using OpenXML, right? With help from the PowerTools for OpenXML? Official boat-load, as in supertanker, sized OpenXML content list (Insert "One OpenXML content list to rule them all" here) So how do I get from here to OpenXML? Got a map for you, an Open XML SDK Blog Map… Where to go to scratch your OpenXML dev info itch… "Open XML Explained" Free eBook (PDF) The Noob's Guide to Open XML Dev (If you know how to spell OpenXML but that's about it, this is your Getting Started guide...) Reusing the PowerShell PowerTools for Open XML in your C# or VB.Net world PowerShell, OpenXML, WMI and the PowerTools for OpenXML = Doc generation for our inner geek Because it’s a PowerShell kind of day… PowerTools for Open XML V1.1 Released OpenXML PowerTools updated – Cell your Excel via PowerShell Powering into OpenXML with PowerShell Open XML SDK 2.0 for Microsoft Office Released – Automate Office documents without Office Open XML 2.0 Code Snippets for VS2010 (and VS2008 too) Open XML Format SDK 2.0 Code Snippets for Visual Studio 2008 – 52 C#/VB Code Snippets to help ease your Open XML coding Open XML File Format Code Snippets for Visual Studio 2005 (Office 2007 NOT required) Open XML SDK v1 Released OpenXML Viewer 1.0 Released – Open source DocX to HTML conversion, with IE, Firefox and Opera (and/or command line) support

This article was originally published in DZone's 2014 Guide to Mobile Development Mobile development has become a ubiquitous part of the software industry, and most developers understand the central dilemma organizations face when building a mobile app: cross-platform development. What options exist for deploying an app to multiple platforms simultaneously? What are the strengths and weaknesses of each platform? The backbone of mobile development is the native application, but there are a growing number of alternatives: web apps provide a browser-based solution, hybrid apps leverage web development skills in a native package, and code translators apply one platform’s native development skillset to the codebase of another. However, the differences can be subtle, and every option carries its own set of drawbacks. NATIVE DEVELOPMENT Native applications are built from the ground up for a specific platform and tailored to fit it. The precise, platform-centered nature of native development means that these apps have no limits in terms of access to APIs and device features, performance optimization, and platform-specific best practices for user interface design. Ideally, every mobile app would be built this way: to suit its exact purpose while utilizing all of the available resources. One of the major benefits of native mobile development is the availability of resources. For example, developers targeting Android have the Android Software Development Kit (SDK) at their disposal, which includes a suite of tools to streamline the development process: the SDK Manager condenses updates and tool installations into a single menu, the AVD Manager provides access to the Android Emulator and other virtual devices, and the Dalvik Debug Monitor Server (DDMS) is a powerful debugging tool, just to name a few. iOS and Windows Phone developers have similar toolsets available in their SDKs, covering everything from the UI and device feature tools of Cocoa Touch in the iOS SDK to the real world testing conditions of the Simulation Dashboard for Windows Phone 8. These toolsets make native SDKs invaluable and thorough resources. Unfortunately, the native SDKs are all robust toolsets that a native developer has to learn for each platform. To develop native apps from scratch (rather than through an intermediate tool), developers must be skilled with the required language, IDE, and development tools for each targeted platform, and if developers with diverse skillsets are not available, additional developers must be hired. This can be a serious problem, given the increasing push to develop on multiple platforms. For example, according to DZone’s 2014 Mobile Developer Survey, 62% of respondents targeted both Android and iOS. The economic constraints of native development are a major factor in the growing popularity of web apps, hybrid apps, code translators, and Mobile Application Development Platforms (MADPs), which allow developers to reach multiple platforms with just one tooling ecosystem. WEB APPS The skillset for building a basic mobile web app is more common than that of native development. Essentially, mobile web apps are just regular websites optimized to look good and function well on mobile devices, and they can provide a quality app-like experience if the developer is very skilled in web technologies. Widely understood front-end web development languages such as HTML, CSS, and JavaScript provide the logic behind a web app, and there are plenty of tools and libraries out there to help web developers direct their skills toward mobile devices. jQuery Mobile and Sencha Touch are two examples of mobile web frameworks that provide UI components and logic for sliders, swipes, and other touch-activated controls that are common to native mobile applications. The community around open source web technologies is another key difference between native and web development. Web technologies like Node.js and AngularJS are some of the most popular projects in the open source community according to GitHub statistics. This suggests that the community support and knowledge base around web technologies is broader than native technologies. In addition to being a more common skill set, mobile web development can also solve a fundamental issue with native application development. Aside from possible browser compatibility issues, web apps present a near-universal cross-platform option. Most APIs and hardware features will not be accessible by web apps, and because they are not discrete applications in the same way that native apps are, web apps cannot be distributed through common means, such as Apple’s App Store and Google’s Android Marketplace. Web apps may be a particularly flexible option, but they lack a presence on fundamental mobile distribution. HYBRID APPS Many of the drawbacks for web apps are alleviated by another cross-platform option built on the same core web development skillset: the hybrid app. Like web apps, hybrid apps require web development skills, but unlike web apps, they include some native features to allow greater flexibility. It gets the name hybrid because it is built with web languages and technologies at its core. With the help of a native packaging tool, it can be deployed just like a native app and access more native device capabilities (device APIs) than a pure web application. A hybrid app is created by first coding the application to run in the device’s native webview, which is basically a stripped-down version of the browser. For iOS this view is called UIWebView, while on Android it’s called WebView. This view can present the HTML and JavaScript files in a full-screen format, and pure web apps can achieve this full-screen view as well. WebKit is the most commonly targeted browser rendering engine because it is used on iOS, Android, and Blackberry. Where a web app really starts to become a hybrid app is when the app is placed inside of a native wrapper, which packages the hybrid app as a discrete application and makes it viable for app store distribution. In addition to the native wrapper, a native bridge allows the app to communicate with device APIs, such as alarm settings, accelerometers, and cameras. The native bridge is an abstraction layer that exposes the device APIs to the hybrid app as a JavaScript API. This is one feature that clearly separates hybrid and pure web apps, because web apps are unable to pass through the security structures between the browser and native device APIs. Access to many of the hardware features on mobile devices makes hybrid apps feel more like native apps than web apps from the user perspective. MADPS AND CODE TRANSLATORS Some tools can go even further in terms of taking a single codebase and deploying it on multiple mobile platforms. MADPs are development tools, sometimes including a mobile middleware server, that build hybrid or native apps for each platform using one codebase. Some MADPs, such as Appcelerator’s Titanium and Trigger.io, can take advantage of native elements where native is necessary or higher performing. UI widgets may be native, for instance, while a more flexible JavaScript API condenses the universal parts of mobile development and maximizes code reuse. As more native elements are introduced, some of the drawbacks of native development reappear, such as the costly need for multiple skillsets. MADPs are most useful in scenarios where an application needs to work with many back-end data sources, many other mobile apps, or many operating systems. (Inspired by Trigger.io) A less comprehensive but more straightforward solution is to use code translators when building native apps for multiple operating systems. These tools take native code and translate it into another platform’s native code, or translate native code into a neutral low-level alternative, such as bytecode. One example is Google’s J2ObjC, which translates Java classes into their Objective-C equivalents, alleviating a lot the initial development of an iOS version of the app. Although it’s much more than a code translator, a product called Xamarin does something similar by allowing developers working with C# and .NET in Visual Studio to produce a native ARM executable. They can then take advantage of ahead-of-time (AOT) or just-in-time (JIT) compilation to run their apps on iOS and Android in addition to Windows Phone. As is the case with hybrid apps, the UI presents a problem. Because UI development cannot be translated between platforms, code translators still require a significant knowledge of the native platform to write the UI. In other words, code translators can provide substantial benefits in terms of cutting down development time, but they’re not necessarily a “write once, run anywhere” solution. NO SILVER BULLETS Between native apps, web apps, hybrid apps, and the growing number of MADPs, there are a lot of options for mobile development. It’s important to note that there is no one solution that does everything. Some sacrifice affordability and accessibility for pure native performance, UI for easy cross-platform deployment, or ease of development for native authenticity. Even the simplest tools come with some degree of a learning curve. If a method with no trade-offs existed, the industry would adopt it en masse, and you would know about it. Because there are trade-offs, developers and decision-makers will have to recognize their needs, and the needs of their users, in order to determine the best way to approach mobile development. Want to read more articles like this? Download the free guide today! 2014 Guide to Mobile Development DZone's 2014 Guide to Mobile Development provides an analysis of the current state of mobile development and important strategies, tools, and insights for accelerating mobile development and includes: In-depth articles written by industry experts Survey results from over 1000 mobile developers Profiles on 39 mobile developement tools and frameworks And much more! DOWNLOAD NOW