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Reportlab: Mixing Fixed Content and Flowables
Recently I needed the ability to use Reportlab’s flowables, but place them in fixed locations. Some of you are probably wondering why I would want to do that. The nice thing about flowables, like the Paragraph, is that they’re easily styled. If I could bold something or center something AND put it in a fixed location, then that would rock! It took a lot of Googling and trial and error, but I finally got a decent template put together that I could use for mailings. In this article, I’m going to show you how to do this too. Getting Started You’ll need to make sure you have Reportlab or you’ll end up with a whole lot of nothing. You can go here to grab it. While you wait for it to download you can continue reading this article or go do something else productive. Are you ready now? Then let’s get this show on the road! Now we just need to come up with an example. Fortunately I was working on something at my job that I’ve been able to dummy up into the following silly and incomplete form letter. Study the code closely because you never know when there will be a test from reportlab.lib.pagesizes import letter from reportlab.lib.styles import getSampleStyleSheet from reportlab.lib.units import mm, inch from reportlab.pdfgen import canvas from reportlab.platypus import Image, Paragraph, Table ######################################################################## class LetterMaker(object): """""" #---------------------------------------------------------------------- def __init__(self, pdf_file, org, seconds): self.c = canvas.Canvas(pdf_file, pagesize=letter) self.styles = getSampleStyleSheet() self.width, self.height = letter self.organization = org self.seconds = seconds #---------------------------------------------------------------------- def createDocument(self): """""" voffset = 65 # create return address address = """ Jack Spratt 222 Ioway Blvd, Suite 100 Galls, TX 75081-4016 """ p = Paragraph(address, self.styles["Normal"]) # add a logo and size it logo = Image("snakehead.jpg") logo.drawHeight = 2*inch logo.drawWidth = 2*inch ## logo.wrapOn(self.c, self.width, self.height) ## logo.drawOn(self.c, *self.coord(140, 60, mm)) ## data = [[p, logo]] table = Table(data, colWidths=4*inch) table.setStyle([("VALIGN", (0,0), (0,0), "TOP")]) table.wrapOn(self.c, self.width, self.height) table.drawOn(self.c, *self.coord(18, 60, mm)) # insert body of letter ptext = "Dear Sir or Madam:" self.createParagraph(ptext, 20, voffset+35) ptext = """ The document you are holding is a set of requirements for your next mission, should you choose to accept it. In any event, this document will self-destruct %s seconds after you read it. Yes, %s can tell when you're done...usually. """ % (self.seconds, self.organization) p = Paragraph(ptext, self.styles["Normal"]) p.wrapOn(self.c, self.width-70, self.height) p.drawOn(self.c, *self.coord(20, voffset+48, mm)) #---------------------------------------------------------------------- def coord(self, x, y, unit=1): """ # http://stackoverflow.com/questions/4726011/wrap-text-in-a-table-reportlab Helper class to help position flowables in Canvas objects """ x, y = x * unit, self.height - y * unit return x, y #---------------------------------------------------------------------- def createParagraph(self, ptext, x, y, style=None): """""" if not style: style = self.styles["Normal"] p = Paragraph(ptext, style=style) p.wrapOn(self.c, self.width, self.height) p.drawOn(self.c, *self.coord(x, y, mm)) #---------------------------------------------------------------------- def savePDF(self): """""" self.c.save() #---------------------------------------------------------------------- if __name__ == "__main__": doc = LetterMaker("example.pdf", "The MVP", 10) doc.createDocument() doc.savePDF() Now you’ve seen the code, so we’ll spend a little time going over how it works. First off we create a Canvas object that we can use without our LetterMaker class. We also create a styles dict and set up a few other class variables. In the createDocument method, we create a Paragraph (an address) using some HTML-like tags to control the font and line breaking behavior. Then we create a logo and size it before putting both items into a Reportlab Table object. You’ll note that I’ve left in a couple commented out lines that show how to place the logo without the table. We use the coord method to help position the flowable. I found it on StackOverflow and thought it was pretty handy. The body of the letter uses a little string substitution and puts the result into another Paragraph. We also use a stored offset to help us position things. I find that storing a couple of offsets for certain portions of the code is very helpful. If you use them carefully then you can just change a couple of offsets to move the content around on the document rather than having to edit the position of each element. If you need to draw lines or shapes, you can do them in the usual way with your canvas object. Wrapping Up I hope this code will help you in your PDF creation endeavors. I have to admit that I’m posting it on here as much for my own future benefit as for your own. I’m a little sad I had to strip out so much from it, but my organization wouldn’t like it very much if I posted the original. Regardless, you now have the tools to create some pretty fancy PDF documents with Python. Now you just have to get out there and do it!
June 29, 2012
by Mike Driscoll
· 19,917 Views
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Continuous Delivery vs. Traditional Agile
in working with development teams at organizations which are adopting continuous delivery , i have found there can be friction over practices that many developers have come to consider as the right way for agile teams to work. i believe the root of conflicts between what i’ve come to think of as traditional agile and cd is the approach to making software “ready for release”. evolution of software delivery a usefully simplistic view of the evolution of ideas about making software ready for release is this: waterfall believes a team should only start making its software ready for release when all of the functionality for the release has been developed (i.e. when it is “feature complete”). agile introduces the idea that the team should get their software ready for release throughout development. many variations of agile (which i refer to as “traditional agile” in this post) believe this should be done at periodic intervals. continuous delivery is another subset of agile which in which the team keeps its software ready for release at all times during development. it is different from “traditional” agile in that it does not involve stopping and making a special effort to create a releasable build. continuous delivery is not about shorter cycles going from traditional agile development to continuous delivery is not about adopting a shorter cycle for making the software ready for release. making releasable builds every night is still not continuous delivery. cd is about moving away from making the software ready as a separate activity, and instead developing in a way that means the software is always ready for release. ready for release does not mean actually releasing a common misunderstanding is that continuous delivery means releasing into production very frequently. this confusion is made worse by the use of organizations that release software multiple times every day as poster children for cd. continuous delivery doesn’t require frequent releases, it only requires ensuring software could be released with very little effort at any point during development. (see jez humble’s article on continuous delivery vs. continuous deployment .) although developing this capability opens opportunities which may encourage the organization to release more often, many teams find more than enough benefit from cd practices to justify using it even when releases are fairly infrequent. friction points between continuous delivery and traditional agile as i mentioned, there are sometimes conflicts between continuous delivery and practices that development teams take for granted as being “proper” agile. friction point: software with unfinished work can still be releasable one of these points of friction is the requirement that the codebase not include incomplete stories or bugfixes at the end of the iteration. i explored this in my previous post on iterations . this requirement comes from the idea that the end of the iteration is the point where the team stops and does the extra work needed to prepare the software for release. but when a team adopts continuous delivery, there is no additional work needed to make the software releasable. more to the point, the cd team ensures that their code could be released to production even when they have work in progress, using techniques such as feature toggles . this in turn means that the team can meet the requirement that they be ready for release at the end of the iteration even with unfinished stories. this can be a bit difficult for people to swallow. the team can certainly still require all work to be complete at the iteration boundary, but this starts to feel like an arbitrary constraint that breaks the team’s flow. continuous delivery doesn’t require non-timeboxed iterations, but the two practices are complementary. friction point: snapshot/release builds many development teams divide software builds into two types, “snapshot” builds and “release” builds. this is not specific to agile, but has become strongly embedded in the java world due to the rise of maven, which puts the snapshot/build concept at the core of its design. this approach divides the development cycle into two phases, with snapshots being used while software is in development, and a release build being created only when the software is deemed ready for release. this division of the release cycle clearly conflicts with the continuous delivery philosophy that software should always be ready for release. the way cd is typically implemented involves only creating a build once, and then promoting it through multiple stages of a pipeline for testing and validation activities, which doesn’t work if software is built in two different ways as with maven. it’s entirely possible to use maven with continuous delivery, for example by creating a release build for every build in the pipeline. however this leads to friction with maven tools and infrastructure that assume release builds are infrequent and intended for production deployment. for example, artefact repositories such as nexus and artefactory have housekeeping features to delete old snapshot builds, but don’t allow release builds to be deleted. so an active cd team, which may produce dozens of builds a day, can easily chew through gigabytes and terabytes of disk space on the repository. friction point: heavier focus on testing deployability a standard practice with continuous delivery is automatically deploying every build that passes basic continuous integration to an environment that emulates production as closely as possible, using the same deployment process and tooling. this is essential to proving whether the code is ready for release on every commit, but this is more rigorous than many development teams are used to having in their ci. for example, pre-cd continuous integration might run automated functional tests against the application by deploying it to an embedded application server using a build tool like ant or maven. this is easier for developers to use and maintain, but is probably not how the application will be deployed in production. so a cd team will typically add an automated deployment to an environment will more fully replicates production, including separated web/app/data tiers, and deployment tooling that will be used in production. however this more production-like deployment stage is more likely to fail due to its added complexity, and may be may be more difficult for developers to maintain and fix since it uses tooling more familiar to system administrators than to developers. this can be an opportunity to work more closely with the operations team to create a more reliable, easily supported deployment process. but it is likely to be a steep curve to implement and stabilize this process, which may impact development productivity. is cd worth it? given these friction points, what benefit is there to moving from traditional agile to continuous delivery worthwhile, especially for a team that is unlikely to actually release into production more often than every iteration? decrease risk by uncovering deployment issues earlier, increase flexibility by giving the organization the option to release at any point with minimal added cost or risk, involves everyone involved in production releases - such as qa, operations, etc. - in making the full process more efficient. the entire organization must identify difficult areas of the process and find ways to fix them, through automation, better collaboration, and improved working practices, by continuously rehearsing the release process, the organization becomes more competent at doing it, so that releasing becomes autonomic, like breathing, rather than traumatic, like giving birth, improves the quality of the software, by forcing the team to fix problems as they are found rather than being able to leave things for later. dealing with the friction the friction points i’ve described seem to come up fairly often when continuous delivery is being introduced. my hope is that understanding the source of this friction will be helpful in discussing it when it comes up, and working through the issues. if developers who are initially uncomfortable with breaking with the “proper” way of doing things, or find a cd pipeline overly complex or difficult understand the aims and value of these practices, hopefully they will be more open to giving them a chance. once these practices become embedded and mature in an organization, team members often find it’s difficult to go back to the old ways of doing them. edit: i’ve rephrased the definition of the “traditional agile” approach to making software ready for release. this definition is not meant to apply to all agile practices, but rather applies to what seems to me to be a fairly mainstream belief that agile means stopping work to make the software releasable.
May 9, 2012
by Kief Morris
· 54,201 Views · 7 Likes
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Lean Tools: the Last Responsible Moment
Options Thinking lead us to invest time and money in delaying decisions to a time where we know the most about it; the extreme application of the Decide as late as possible principle is the concept of Last Responsible Moment, the optimal point of the trade-off between the available time for a decision and the need to complete a story or a task. The last responsible moment is the instant in which the cost of the delay of a decision surpasses the benefit of delay; or the moment when failing to take a decision eliminates an important alternative. For example, failing to provide a public HTTP API may make you lose an important customer, forcing you to publish an unfinished work. Tactics Mary Poppendiesk describes several tactics for delaying decisions until the last responsible moment: share partial design information, before it is freezed or released. The irreversible decisions, like freezing an api, are made later after feedback has been gathered; at the same time, the rest of the team can start to work with it. improve the response time for new stories. If you want to make a decision later, you still will have to respect the deadline. The faster you are, the later you can take important decisions. The adjectives lean and agile usually connotates lightweight approaches where decisions can be taken later for maximum flexibility. absorb changes by delaying the commitments to particular implementations, tools, and libraries. Modularization, interfaces, configuration parameters and any kind of abstraction are welcome investments in any case where there is the possibility of change in the future. By the way, the *no extra features* XP mantra recognizes that simple design, which minimizes duplication and moving parts, is the best response to the need for evolution. Real Options The Real Option (still the financial option metaphor) concept motivates Agile practices as for their ability to improve our options for deciding at the last responsible moment. For example, tests give us more options for a design by preserving its ability to change; and pairing give us more options for who should develop a feature, as knowledge of that particular part of the code base is spread across the team instead of being concentrated in a few people. It's all about risk management. Delaying decisions lets us able to make them in conditions of less uncertainty, when we can only know more about the domain and the project. Criticism Alistair Cockburn criticizes the concept of last responsible moment for several reasons. First, since the characterization as a single instant is not so close to reality. Cost and benefits of a decisions are soft functions that vary continuously, so it's difficult to think of a precise moment where a decision must be taken. In most cases, the *moment* spans for days. Second, this concept is not actionable, in the sense that you don't know the point in time where it will take place until after it has passed. Knowing that there is a deadline for a decision is different from knowing it with absolute precision. Finally, Cockburn views it as simple not good advice as trade-offs between cost and benefits should only apply to critical decisions, like a database with an high cost or lock-in, or the hardware architecture of the application. From the Extreme Programming point of view, it is correct to delay commitment to the last responsible moment, but not to overengineer a system to postpone every possible design decision. Choices like the programming language to write code in must be taken at the start of the project; the set of classes and methods should be kept minimal as long as duplication is eliminated. After all, this is a series on tools and it's up to us to pick up the right tool in the right context. The last responsible moment makes sense for decisions which are costly to change, but everything that can be rolledback thanks to encapsulation and information hiding is already abstracted away enough. In fact, iterative development is based on starting with a large set of assumptions and removing them one by one according to priority, evolving the code towards a more general picture. For example I have no problem hardcoding business rules, database drivers choices inside Repositories (but not credentials of course), and web application routes. As long as I can go back to the code in the future, they are not final decision; instead, I try to reserve the delaying of commitment to published interfaces and HTTP APIs... Conclusions We have learned to try to postpone decisions which are not immediately required, and even to invest in finding solutions for postponing some of them even when they should ordinarily be taken at the present time. The last responsible moment is a concept not to be taken literally, but when applied to difficult design and business decisions sets a goal for gathering all the needed information to take a choice when the time comes. Don't worry about what you can still change: worry about what will be carved in stone and delay the related decision as long as it does not damage you.
May 9, 2012
by Giorgio Sironi
· 20,477 Views
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What the Heck is a Utility Tree?
i recently answered this question in stackoverflow : what is an utility tree and what is it’s purpose in case of architecture tradeoff analysis method(atam)? i did answer the question there but here’s a better explanation with lots of examples based on the initial version for chapter 1 of soa patterns (which didn’t make it into the final version of the book). there are two types of requirements for software projects: functional and non-functional requirements. functional requirements are the requirements for what the solution must do (which are usually expressed as use cases or stories). the functional requirements are what the users (or systems) that interact with the system do with the system (fill in an order, update customer details, authorize a loan etc.). non-functional requirements are attributes the system is expected to have or manifest. these usually include requirements in areas such as performance, security, availability etc. a better name for non-functional requirements is “quality attributes” . below are some formal definitions from ieee standad 1061 “standard for a software quality metrics methodology” for quality attributes and related terms: quality attribute a characteristic of software, or a generic term applying to quality factors, quality subfactors, or metric values. quality factor a management-oriented attribute of software that contributes to its quality. quality subfactor a decomposition of a quality factor or quality subfactor to its technical components. metric value a metric output or an element that is from the range of a metric. software quality metric a function whose inputs are software data and whose output is a single numerical value that can beinterpreted as the degree to which software possesses a given attribute that affects its quality. most of the requirements that drive the design of a software architecture comes from system’s quality attributes. the reason for this is that that the effect of quality attributes is usually system-wide (e.g. you wouldn’t want your system to have good performance only in the ui – you want the system to perform well no matter what) – which is exactly what software architecture is concerned with. note however, that few requirements might still come from functional requirements) [1] . the question is how do we find out what those requirements are? the answer to that is also in the software architecture definition. the source for quality attributes are the stakeholders. so what or who are these “stakeholders”? well, a stakeholder is just about anyone who has a vested interest in the project. a typical system has a lot of stakeholders starting from the (obvious) customer, the end-users (those people in the customer organization/dept that will actually use the software) and going to the operations personnel (it – those who will have to keep the solution running), the development team, testers, maintainers, management. in some systems the stakeholders can even be the shareholders or even the general public (imagine for example, that you build a new dispatch system for a 911 center). one of the architect’s roles is to analyze the quality attributes and define an architecture that will enable delivering all the functional requirements while supporting the quality attributes. as can be expected ,sometimes quality attributes are in conflict with each other – the most obvious examples are performance vs. security or flexibility vs. simplicity and the architect’s role is to strike a balance between the different quality attributes (and the stakeholders) to make sure the overall quality of the system is maximized. contextual solutions (e.g. patterns) can be devised to solve specific quality attributes need. however saying that a system needs to have “good performance” or that it needs to be “testable” doesn’t really help us know what to do. in order for us to be able to discern which patterns apply to specific quality attribute , we need a better understanding of quality attributes besides the formal definition, something that is more concrete. the way to get that concrete understanding of the effect of quality attributes is to use scenarios. scenarios are short, “user story”-like proses that demonstrate how a quality attribute is manifested in the system using a functional situation quality attributes scenarios originated as a way to evaluate software architecture. the software engineering institute developed several evaluation methodologies, like architecture tradeoff analysis method (clements, kazman and klein, 2002) that heavily build on scenarios to contrast and compare how the different quality attributes are met by candidate architectures. atam (and similar evaluation methods like laaam which is part of msf 4.0) suggest building a “utility tree” which represent the overall usefulness of the system. the scenarios serve as the leafs of the utility tree and the architecture is evaluated by considering how the architecture makes the scenarios possible. i found that using scenarios and the utility tree approach early in the design of the architecture (see writings about saf ) can greatly enhance the quality of the architecture that is produced. when you examine the scenarios you can also prioritize them and better balance conflicting attributes. the scenarios can be used as an input to make sure the quality attributes are actually met. furthermore you can use the scenarios to help identify the strategies or patterns applicable to make the scenarios possible (and thus ensure the quality attributes are met) within the system. we usually group scenarios into a “utility tree” which is a representation of the total usefulness (“utility”) of a system . as you can see in the diagram below we have the key quality attributes (performance, security etc.). each of the quality attributes has sub categories (e.g. performance is broken into latency, data loss etc.). each sub category is demonstrated by a scenario that we expect the system to manifest. the tree representation helps get the whole picture but the important bits here are the scenarios so let’s explore them some more. scenarios are expressed as statements that have 3 parts: a stimulus , a context and a response . the stimulus is the action taken (by the system / user/ other system / any other person); response is how the system is expected to behave when the stimulus occur, and the context specifies the environment or conditions under which we expect the to get the response. for example in the following scenario: “when you perform a database operation , under normal condition, it should take less than 100 miliseconds.” “under normal condition” is the context “when you perform a database operation” is the stimulus “it should take less than 100 millisecond” is the response expected from the system. here are a couple of additional examples for quality attribute scenarios: performance –>latency -> under normal conditions a client consuming multiple services should have latency less than 5 seconds. security->authentications -> under all conditions, any call to a service should be authenticated using x.509 certificate you can also check out this document for a few more scenario examples from a system i worked on in the past [1] design has the ratios reversed i.e. most of the requirements for design come from functional requirements and a few requirements might come from the quality attributes. illustration by epsos.de
May 9, 2012
by Arnon Rotem-gal-oz
· 19,480 Views
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Lean tools: Options thinking
We now have finished exploring the Lean tools for amplifying learning like feedback, iterations and set-based development. We enter the real of the 3rd Lean principle, Decide as late as possible. This principle is oriented to postpone decisions as long as the delay does not impact the product, in order to gain more flexibility instead of becoming locked in with some initial design decisions. Software is easy to rebuild from source code, but its architecture is not always malleable by default as non-technical people would think. Moreover, there are some changes which will always happen, like upgrade of libraries and operating systems, which complements change in requirements or integration ports. The easiest decision to change is the one that has not been made yet. Options Thinking The first tool that helps in postponing decisions is Options Thinking: the introduction of mechanisms whose specific purpose is to enable delaying decisions. In the financial domain, an option is the right to buy a good at a certain price before a future date comes - effectively transferring the decision of buying shares or products some time in the future, as options can expire without being exercised. A simpler instance of Options Thinking cited by Mary Poppendieck is an hotel reservation: you invest a small sum of money (the reservation fee) to book a room; exercising the option means actually going to the hotel, a decision which is made only when the time comes. Trains and airlines often use the same pricing model for seats (even if we do not consider the rise of prices as a flight is being filled). There are multiple types of tickets for each combination of flight and date: some basic and not transferrable or refundable, some more costly that provide the option of changing the date or to get a partial or total refund. Agile Mary Poppendieck adds the insight that Agile software development is a process that creates many options by introducing a very flexible plan and only prescribing more detailed actions after several inspect and adapt loops. It's not bad to delay a commitment until you know more about a problem: forced early decisions are the mark of waterfall (actually of the mainstream version of waterfall). But options do not come for free: for example, in order to simplify a technical decision, XP suggests to create throwaway code. These spikes are the exploration of each potential solution, which in a certain sense are a waste of development time as their final result is of low quality and usually thrown away. However, spikes produces knowledge about the solution that results in a better estimate for its full development or in its abandonment. The decision to adopt a technology or of which solution to adopt is delayed until the end of a spike, but this option pay itself quickly as uncertainty is removed and decisions "get it right" with an higher probability. Real world examples Almost any application I have been involved with in the last two years has had the separation of a persistence layer as one of the goals: Active Record has been progressively abandoned in the PHP world to favor Data Mappers like the Doctrine ORM and ODMs. As for all options that can be bought, this separation does not come for free: development is a little slower when Repositories are objects that have to be designed instead of just a bunch of static calls to the Entity class like User::find() (although there are benefits of the Data Mapper approach that go beyond keeping options open.) An isolated persistence layer, however, allows us to postpone fundamental decisions about the database to use: it's a rough time for many of them as licenses change (MySQL) or new NoSQL solutions come out and evolve. Every month of development where you're not tied to a specific database is a month where the hype goes down and we move towards more mature solutions that we can choose with a greater knowledge of the requirements of our data. Do we need relational database consistency? Or a schema-less store? Moreover, the investment in persistence adapters separated from the core of the application let us able to choose different databases for different bounded contexts of an application; for example, storing views in a relational database and the primary database as a set of aggregates in Couch or Mongo. Conclusion I will never advocate to invest in an option just for the sake of the technical challenge, nor that they come for free; but once you recognize postponing a decision freezing is valuable for the project, there should be really no issue in go and buying it.
May 2, 2012
by Giorgio Sironi
· 10,420 Views
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Amazon EMR Tutorial: Running a Hadoop MapReduce Job Using Custom JAR
See original post at https://muhammadkhojaye.blogspot.com/2012/04/how-to-run-amazon-elastic-mapreduce-job.html Introduction Amazon EMR is a web service which can be used to easily and efficiently process enormous amounts of data. It uses a hosted Hadoop framework running on the web-scale infrastructure of Amazon EC2 and Amazon S3. Amazon EMR removes most of the cumbersome details of Hadoop while taking care of provisioning of Hadoop, running the job flow, terminating the job flow, moving the data between Amazon EC2 and Amazon S3, and optimizing Hadoop. In this tutorial, we will use a developed WordCount Java example using Hadoop and thereafter, we execute our program on Amazon Elastic MapReduce. Prerequisites You must have valid AWS account credentials. You should also have a general familiarity with using the Eclipse IDE before you begin. The reader can also use any other IDE of their choice. Step 1 – Develop MapReduce WordCount Java Program In this section, we are first going to develop a WordCount application. A WordCount program will determine how many times different words appear in a set of files. In Eclipse (or whatever the IDE you are using), Create simple Java Project with the name "WordCount". Create a java class name Map and override the map method as follow, public class Map extends Mapper { private final static IntWritable one = new IntWritable(1); private Text word = new Text(); @Override public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException { String line = value.toString(); StringTokenizer tokenizer = new StringTokenizer(line); while (tokenizer.hasMoreTokens()) { word.set(tokenizer.nextToken()); context.write(word, one); } } } Create a java class named Reduce and override the reduce method as shown below, public class Reduce extends Reducer { @Override protected void reduce(Text key, java.lang.Iterable values, org.apache.hadoop.mapreduce.Reducer.Context context) throws IOException, InterruptedException { int sum = 0; for (IntWritable value : values) { sum += value.get(); } context.write(key, new IntWritable(sum)); } } Create a java class named WordCount and defined the main method as below, public static void main(String[] args) throws Exception { Configuration conf = new Configuration(); Job job = new Job(conf, "wordcount"); job.setJarByClass(WordCount.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(IntWritable.class); job.setMapperClass(Map.class); job.setReducerClass(Reduce.class); job.setInputFormatClass(TextInputFormat.class); job.setOutputFormatClass(TextOutputFormat.class); FileInputFormat.addInputPath(job, new Path(args[0])); FileOutputFormat.setOutputPath(job, new Path(args[1])); job.waitForCompletion(true); } Export the WordCount program in a jar using eclipse and save it to some location on disk. Make sure that you have provided the Main Class (WordCount.jar) during extraction ofu8u the jar file as shown below. Our jar is ready!!! Step 2 – Upload the WordCount JAR and Input Files to Amazon S3 Now we are going to upload the WordCount jar to Amazon S3. First, go to the following URL: https://console.aws.amazon.com/s3/home Next, click “Create Bucket”, give your bucket a name, and click the “Create” button. Select your new S3 bucket in the left-hand pane. Upload the WordCount JAR and sample input file for counting the words. Step 3 – Running an Elastic MapReduce job Now that the JAR is uploaded into S3, all we need to do is to create a new Job flow. let's execute the steps below. (I encourage readers to check out the following link for details regarding each step, How to Create a Job Flow Using a Custom JAR ) Sign in to the AWS Management Console and open the Amazon Elastic MapReduce console at https://console.aws.amazon.com/elasticmapreduce/ Click Create New Job Flow. In the DEFINE JOB FLOW page, enter the following details, a) Job Flow Name = WordCountJob b) Select Run your own applications) Select Custom JAR in the drop-down list) Click Continue In the SPECIFY PARAMETERS page, enter values in the boxes using the following table as a guide, and then click Continue.JAR Location = bucketName/jarFileLocationJAR Arguments =s3n://bucketName/inputFileLocations3n://bucketName/outputpath Please note that the output path must be unique each time we execute the job. The Hadoop always create a folder with the same name specified here. After executing the job, just wait and monitor your job that runs through the Hadoop flow. You can also look for errors by using the Debug button. The job should be complete within 10 to 15 minutes (can also depend on the size of the input). After completing the job, You can view results in the S3 Browser panel. You can also download the files from S3 and can analyze the outcome of the job. Amazon Elastic MapReduce Resources Amazon Elastic MapReduce Documentation,http://aws.amazon.com/documentation/elasticmapreduce/ Amazon Elastic MapReduce Getting Started Guide,http://docs.amazonwebservices.com/ElasticMapReduce/latest/GettingStartedGuide/ Amazon Elastic MapReduce Developer Guide,http://docs.amazonwebservices.com/ElasticMapReduce/latest/DeveloperGuide/ Apache Hadoop,http://hadoop.apache.org/ See more at https://muhammadkhojaye.blogspot.com/2012/04/how-to-run-amazon-elastic-mapreduce-job.html
April 23, 2012
by Muhammad Ali Khojaye
· 59,075 Views
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Face Detection using HTML5, Javascript, Webrtc, Websockets, Jetty and OpenCV
How to create a real-time face detection system using HTML5, JavaScript, and OpenCV, leveraging WebRTC for webcam access and WebSockets for client-server communication.
April 23, 2012
by Jos Dirksen
· 53,149 Views
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Scheduling a Job Using The NCron Library
Introduction NCron is a .Net scheduling framework, it is a .Net version of Cron - the time based job scheduler found on unix like operating systems or Cron4j - scheduling library for Java. Ncron is light weight and easy to use, with little learning curve. It comes with some cool advantages, being that you can use it in C#, Vb.net or any other .Net programming language. It takes your mind off the details of scheduling and you can focus on how to implement the business logic of your application or the job to be scheduled. Details such as threading and timers have been taken care of. Ncron Library You can point your browser to http://code.google.com/p/ncron/downloads/detail?name=ncron-2.1.zip to download the ncron library. You need to add reference to the Ncron library in your project so as to be able to access the classes and functionalities of the Ncron scheduling framework. Scheduling a Job When creating a job to be scheduled using NCron, the job is wrapped up in a class which must extend the class NCron.CronJob and override a void method Execute public class MyJob : NCron.CronJob { public override void Execute() { System.IO.File.Copy(@"c:\\output.out", @"f:\\output.out"); } } The job to be scheduled will be placed in the Execute method. The next thing to do is to give NCron control over the job execution, by calling the static method Bootstrap.Init() at the entry point of your application, for example this can be put in the Main method. You should have a static setup method, which I called JobSetup method that will be passed into the Bootstrap.Init() method. using System; using System.Collections.Generic; using System.Linq; using System.Text; using NCron.Fluent.Crontab; using NCron.Fluent.Generics; using NCron.Service; namespace NcronExample { public class Program { private static void Main(string[] args) { Bootstrap.Init(args, JobSetup); } private static void JobSetup(SchedulingService schedulingService) { schedulingService.At("* * * * *").Run(); } } } The line of code inside the JobSetup method is to specify how the Job is going to be run, and the parameter in the schedulingService.At() method is known as crontab expression which I will discuss shortly. The SchedulingService class has a number of methods of interest. service.Daily().Run(); //runs the scheduled job once every day service.Hourly().Run(); //runs the scheduled job once every hour service.Weekly().Run(); //runs the scheduled job once every week Crontab Expression A crontab expression is a string comprising of 5 characters, which are seperated by space. This crontab expression when parsed produces occurrences of time based on a given schedule expressed in the crontab format. NCron parses crontab expression through the use of NCrontab(Crontab for .Net) an open source library for parsing crontab expressions. A regular crontab expression is of the form * * * * * where the first * is for minute which can be from 0-59. The second * is for hour which can also be from 0-23. The third * is for day of the month from 1-31. The fourth * is for month from 1-12. The last * is for day of week from 0-6 where 0 represents Sunday. The asterisk or wildcard character if left in the expression indicates all valid or legal values for that column. If yIf you want the scheduled job to run every minute, the expresion will be in the form below. * * * * * The The expression below causes the scheduler to run the job at the fifth minute of every ninth hour everyday. 5 9 * * * To run a job every tenth minute of every hour from Monday to Friday only, the expression will be in the form below. 10 * * * 1,2,3,4,5 You can read more on crontab expressions at http://code.google.com/p/ncrontab/wiki/CrontabExamples Deploying the Scheduled Job After the application has been built and compiled, you can deploy the scheduled job as a service by opening command prompt and change directory to where the executable of the application is and then run the command. ncronexample install To install the scheduled job as a service, and that is it !!!
April 18, 2012
by Ayobami Adewole
· 17,511 Views
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Quartz Scheduler Misfire Instructions Explained
Sometimes Quartz is not capable of running your job at the time when you desired. There are three reasons for that: all worker threads were busy running other jobs (probably with higher priority) the scheduler itself was down the job was scheduled with start time in the past (probably a coding error) You can increase the number of worker threads by simply customizing the org.quartz.threadPool.threadCount in quartz.properties (default is 10). But you cannot really do anything when the whole application/server/scheduler was down. The situation when Quartz was incapable of firing given trigger is called misfire. Do you know what Quartz is doing when it happens? Turns out there are various strategies (called misfire instructions) Quartz can take and also there are some defaults if you haven't thought about it. But in order to make your application robust and predictable (especially under heavy load or maintenance) you should really make sure your triggers and jobs are configured conciously. There are different configuration options (available misfire instructions) depending on the trigger chosen. Also Quartz behaves differently depending on trigger setup (so called smart policy). Although the misfire instructions are described in the documentation, I found it hard to understand what do they really mean. So I created this small summary article. Before I dive into the details, there is yet another configuration option that should be described. It is org.quartz.jobStore.misfireThreshold (in milliseconds), defaulting to 60000 (a minute). It defines how late the trigger should be to be considered misfired. With default setup if trigger was suppose to be fired 30 seconds ago, Quartz will happily just run it. Such delay is not considered misfiring. However if the trigger is discovered 61 seconds after the scheduled time - the special misfire handler thread takes care of it, obeying the misfire instruction. For test purposes we will set this parameter to 1000 (1 second) so that we can test misfiring quickly. Simple trigger without repeating In our first example we will see how misfiring is handled by simple triggers scheduled to run only once: val trigger = newTrigger(). startAt(DateUtils.addSeconds(new Date(), -10)). build() The same trigger but with explicitly set misfire instruction handler: val trigger = newTrigger(). startAt(DateUtils.addSeconds(new Date(), -10)). withSchedule( simpleSchedule(). withMisfireHandlingInstructionFireNow() //MISFIRE_INSTRUCTION_FIRE_NOW ). build() For the purpose of testing I am simply scheduling the trigger to run 10 seconds ago (so it is 10 seconds late by the time it is created!) In real world you would normally never schedule triggers like that. Instead imagine the trigger was set correctly but by the time it was scheduled the scheduler was down or didn't have any free worker threads. Nevertheless, how will Quartz handle this extraordinary situation? In the first code snippet above no misfire handling instruction is set (so called smart policy is used in that case). The second code snippet explicitly defines what kind of behaviour do we expect when misfiring occurs. See the table: Instruction Meaning smart policy - default See: withMisfireHandlingInstructionFireNow withMisfireHandlingInstructionFireNow MISFIRE_INSTRUCTION_FIRE_NOW The job is executed immediately after the scheduler discovers misfire situation. This is the smart policy. Example scenario: you have scheduled some system clean up at 2 AM. Unfortunately the application was down due to maintenance by that time and brought back on 3 AM. So the trigger misfired and the scheduler tries to save the situation by running it as soon as it can - at 3 AM. withMisfireHandlingInstructionIgnoreMisfires MISFIRE_INSTRUCTION_IGNORE_MISFIRE_POLICY QTZ-283 See: withMisfireHandlingInstructionFireNow withMisfireHandlingInstructionNextWithExistingCount MISFIRE_INSTRUCTION_RESCHEDULE_NEXT_WITH_EXISTING_COUNT See: withMisfireHandlingInstructionNextWithRemainingCount withMisfireHandlingInstructionNextWithRemainingCount MISFIRE_INSTRUCTION_RESCHEDULE_NEXT_WITH_REMAINING_COUNT Does nothing, misfired execution is ignored and there is no next execution. Use this instruction when you want to completely discard the misfired execution. Example scenario: the trigger was suppose to start recording of a program in TV. There is no point of starting recording when the trigger misfired and is already 2 hours late. withMisfireHandlingInstructionNowWithExistingCount MISFIRE_INSTRUCTION_RESCHEDULE_NOW_WITH_EXISTING_REPEAT_COUNT See: withMisfireHandlingInstructionFireNow withMisfireHandlingInstructionNowWithRemainingCount MISFIRE_INSTRUCTION_RESCHEDULE_NOW_WITH_REMAINING_REPEAT_COUNT See: withMisfireHandlingInstructionFireNow Simple trigger repeating fixed number of times This scenario is much more complicated. Imagine we have scheduled some job to repeat fixed number of times: val trigger = newTrigger(). startAt(dateOf(9, 0, 0)). withSchedule( simpleSchedule(). withRepeatCount(7). withIntervalInHours(1). WithMisfireHandlingInstructionFireNow() //or other ). build() In this example the trigger is suppose to fire 8 times (first execution + 7 repetitions) every hour, beginning at 9 AM today (startAt(dateOf(9, 0, 0)). Thus the last execution should occur at 4 PM. However assume that due to some reason the scheduler was not capable of running jobs at 9 and 10 AM and it discovered that fact at 10:15 AM, i.e. 2 firings misfired. How will the scheduler behave in this situation? Instruction Meaning smart policy - default See: withMisfireHandlingInstructionNowWithExistingCount withMisfireHandlingInstructionFireNow MISFIRE_INSTRUCTION_FIRE_NOW See: withMisfireHandlingInstructionNowWithRemainingCount withMisfireHandlingInstructionIgnoreMisfires MISFIRE_INSTRUCTION_IGNORE_MISFIRE_POLICYQTZ-283 Fires all triggers that were missed as soon as possible and then goes back to ordinary schedule. Example scenario: With this strategy in our example the scheduler will fire jobs scheduled at 9 and 10 AM immediately. Then it will wait to 11 AM and go back to ordinary schedule. Note: When handling misfires it is equally important to realize that the actual job execution time might be way after the scheduled time. This means you cannot simply rely on current system date, but you need to use JobExecutionContext .getScheduledFireTime(): def execute(context: JobExecutionContext) { val date = context.getScheduledFireTime //... } withMisfireHandlingInstructionNextWithExistingCount MISFIRE_INSTRUCTION_RESCHEDULE_NEXT_WITH_EXISTING_COUNT The scheduler won't do anything immediately. Instead it will wait for next scheduled time and run all triggers with scheduled intervals. See also: withMisfireHandlingInstructionNextWithRemainingCount Example scenario: at 10:15 the scheduler discovers 2 misfired executions. It waits until next scheduled time (11 AM) and fires all 8 scheduled executions every hour, stopping at 6 PM (the trigger should have stopped at 4 PM). withMisfireHandlingInstructionNextWithRemainingCount MISFIRE_INSTRUCTION_RESCHEDULE_NEXT_WITH_REMAINING_COUNT The scheduler discards misfired executions and waits for the next scheduled time. The total number of trigger executions will be less then configured. Example scenario: at 10:15 two misfired executions are discarded. The scheduler waits for next scheduled time (11 AM) and fires remaining triggers up to 4 PM. Effectively it behaves as if misfire never occurred. withMisfireHandlingInstructionNowWithExistingCount MISFIRE_INSTRUCTION_RESCHEDULE_NOW_WITH_EXISTING_REPEAT_COUNT First misfired trigger is executed immediately. Then the scheduler waits desired interval and executes all remaining triggers. Effectively the first fire time of the misfired trigger is moved to current time with no other changes. Example scenario: at 10:15 the scheduler runs the first misfired execution. Then it waits 1 hour and fires the second one at 11:15 AM. All 8 executions are performed, the last one at 5:15 PM withMisfireHandlingInstructionNowWithRemainingCount MISFIRE_INSTRUCTION_RESCHEDULE_NOW_WITH_REMAINING_REPEAT_COUNT First misfired execution runs immediately. Remaining misfired executions are discarded. Triggers that were not misfired are executed with desired interval. Example scenario: at 10:15 the scheduler runs the first misfired execution (from 9 AM). It discards remaining misfired executions (the one from 10 AM) and waits 1 hour to execute six more triggers: 11:15, 12:15, … 4:15 PM Simple trigger repeating infinitely In this scenario trigger repeats infinite number of times at a given interval: val trigger = newTrigger(). startAt(dateOf(9, 0, 0)). withSchedule( simpleSchedule(). withRepeatCount(SimpleTrigger.REPEAT_INDEFINITELY). withIntervalInHours(1). WithMisfireHandlingInstructionFireNow() //or other ). build() Once again trigger should fire on every hour, beginning at 9 AM today (startAt(dateOf(9, 0, 0)). However the scheduler was not capable of running jobs at 9 and 10 AM and it discovered that fact at 10:15 AM, i.e. 2 firings misfired. This is a more general situation compared to simple trigger running fixed number of times. Instruction Meaning smart policy - default See: withMisfireHandlingInstructionNextWithRemainingCount withMisfireHandlingInstructionFireNow MISFIRE_INSTRUCTION_FIRE_NOW See: withMisfireHandlingInstructionNowWithRemainingCount withMisfireHandlingInstructionIgnoreMisfires MISFIRE_INSTRUCTION_IGNORE_MISFIRE_POLICYQTZ-283 The scheduler will immediately run all misfired triggers, then continue on schedule. Example scenario: the triggers scheduled at 9 and 10 AM are executed immediately. Future invocations (next scheduled at 11 AM) are executed according to the plan. withMisfireHandlingInstructionNextWithExistingCount MISFIRE_INSTRUCTION_RESCHEDULE_NEXT_WITH_EXISTING_COUNT See: withMisfireHandlingInstructionNextWithRemainingCount withMisfireHandlingInstructionNextWithRemainingCount MISFIRE_INSTRUCTION_RESCHEDULE_NEXT_WITH_REMAINING_COUNT Does nothing, misfired executions are discarded. Then the scheduler waits for next scheduled interval and goes back to schedule. Example scenario: Misfired execution at 9 and 10 AM are discarded. The first execution occurs at 11 AM. withMisfireHandlingInstructionNowWithExistingCount MISFIRE_INSTRUCTION_RESCHEDULE_NOW_WITH_EXISTING_REPEAT_COUNT See: withMisfireHandlingInstructionNowWithRemainingCount withMisfireHandlingInstructionNowWithRemainingCount MISFIRE_INSTRUCTION_RESCHEDULE_NOW_WITH_REMAINING_REPEAT_COUNT The first misfired execution is run immediately, remaining are discarded. Next execution happens after desired interval. Effectively the first execution time is moved to current time. Example scenario: the scheduler fires misfired trigger immediately at 10:15 AM. Then waits an hour and runs the second one at 11:15 AM and continues with 1 hour interval. CRON triggers CRON triggers are the most popular ones amongst Quartz users. However there are also two other available triggers: DailyTimeIntervalTrigger (e.g. fire every 25 minutes) and CalendarIntervalTrigger (e.g. fire every 5 months). They support triggering policies not possible in both CRON and simple triggers. However they understand the same misfire handling instructions as CRON trigger. val trigger = newTrigger(). withSchedule( cronSchedule("0 0 9-17 ? * MON-FRI"). withMisfireHandlingInstructionFireAndProceed() //or other ). build() In this example the trigger should fire every hour between 9 AM and 5 PM, from Monday to Friday. But once again first two invocations were missed (so the trigger misfired) and this situation was discovered at 10:15 AM. Note that available misfire instructions are different compared to simple triggers: Instruction Meaning smart policy - default See: withMisfireHandlingInstructionFireAndProceed withMisfireHandlingInstructionIgnoreMisfires MISFIRE_INSTRUCTION_IGNORE_MISFIRE_POLICYQTZ-283 All misfired executions are immediately executed, then the trigger runs back on schedule. Example scenario: the executions scheduled at 9 and 10 AM are executed immediately. The next scheduled execution (at 11 AM) runs on time. withMisfireHandlingInstructionFireAndProceed MISFIRE_INSTRUCTION_FIRE_ONCE_NOW Immediately executes first misfired execution and discards other (i.e. all misfired executions are merged together). Then back to schedule. No matter how many trigger executions were missed, only single immediate execution is performed. Example scenario: the executions scheduled at 9 and 10 AM are merged and executed only once (in other words: the execution scheduled at 10 AM is discarded). The next scheduled execution (at 11 AM) runs on time. withMisfireHandlingInstructionDoNothing MISFIRE_INSTRUCTION_DO_NOTHING All misfired executions are discarded, the scheduler simply waits for next scheduled time. Example scenario: the executions scheduled at 9 and 10 AM are discarded, so basically nothing happens. The next scheduled execution (at 11 AM) runs on time. QTZ-283Note: QTZ-283: MISFIRE_INSTRUCTION_IGNORE_MISFIRE_POLICY not working with JDBCJobStore - apparently there is a bug when JDBCJobStore is used, keep an eye on that issue. As you can see various triggers behave differently based on the actual setup. Moreover, even though the so called smart policy is provided, often the decision is based on business requirements. Essentially there are three major strategies: ignore, run immediately and continue and discard and wait for next. They all have different use-cases: Use ignore policies when you want to make sure all scheduled executions were triggered, even if it means multiple misfired triggers will fire. Think about a job that generates report every hour based on orders placed during that last hour. If the server was down for 8 hours, you still want to have that reports generated, as soon as you can. In this case the ignore policies will simply run all triggers scheduled during that 8 hour as fast as scheduler can. They will be several hours late, but will eventually be executed. Use now* policies when there are jobs executing periodically and upon misfire situation they should run as soon as possible, but only once. Think of a job that cleans /tmp directory every minute. If the scheduler was busy for 20 minutes and finally can run this job, you don't want to run in 20 times! One is enough, but make sure it runs as fast it can. Then back to your normal one-minute intervals. Finally next* policies are good when you want to make sure your job runs at particular points in time. For example you need to fetch stock prices quarter past every hour. They change rapidly so if your job misfired and it is already 20 minutes past full hour, don't bother. You missed the correct time by 5 minutes and now you don't really care. It is better to have a gap rather than an inaccurate value. In this case Quartz will skip all misfired executions and simply wait for the next one.
April 13, 2012
by Tomasz Nurkiewicz
· 109,267 Views · 13 Likes
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Configuring Quartz With JDBCJobStore in Spring
I am starting a little series about Quartz scheduler internals, tips and tricks, this is chapter 0 - how to configure persistent job store.
April 7, 2012
by Tomasz Nurkiewicz
· 37,748 Views
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The Two Hand Rule for Meandering Stand Ups
when working with agile teams the daily stand up meeting provides a heart beat to the day and an opportunity for team members to share information. stand up meetings work best when they are short and balance the inputs across all the people in the team. a common problem is stand ups that start running too long. when two hands are raised then it's a signal to move the stand up meeting on the two hands rule sometimes the conversations at stand up can get too detailed or go on too long. for these situations we’ve introduced the “two hands” rule; if anyone thinks the current conversation has gone off topic, or is no longer effective, then they raise a hand. once a second person raises a hand then that’s a sign to stop the conversation and continue with the rest of the stand up. those speaking can continue the conversation after the stand up has finished. this approach makes it easy for people to share their view on the effectiveness of the conversation in a way that reduces the risk of causing offence. it also provides a way for the team to detect and correct its own behaviour. i introduced this idea recently to a team who agreed to give it a try. in a stand up a few days later i was talking with a team member and didn’t realise that our conversation had got too detailed and gone on too long. i missed seeing that two other team members had put their hands up. it wasn’t until one of them spoke up that i noticed! this is one of the characteristics of difficult conversations; we often become blind to signs, easily spotted by others, that the conversation has become ineffective. by agreeing with the team to use the “two hands” rule they helped me detect when they thought i’d become ineffective. the technique can have some downsides though. it can feel direct or confrontational, especially when people first experience it. it’s important to discuss any issues after the stand up and consider reviewing the practice in a retrospective. i’d like to hear your thoughts. have you had stand up meetings that have taken too long? what approaches have you used? if you’ve tried something like the “two hands” rule, how did it go?
March 6, 2012
by Benjamin Mitchell
· 8,989 Views · 1 Like
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Why Having "DevOps" in a Job Title Makes Sense
We’ve been trying to grow our team for a few months now and the title we’re hiring for is Devops Engineer. One of the candidates our recruiters reached out to, let’s call him John, came back to us with a bunch of questions including: How do you feel about hiring someone with a devops title? It’s a very legittimate question, Devops is a cultural and professional movement, so how could it be a job title? What I argued in my reply to this fella is that Devops isn’t the job title, Devops Engineer is, and in this sense Devops is just a qualifier and I strongly believe a very useful one. I really sympathise with those that are fighting hard to keep Devops real and avoid the same faith that some refer to as the sad commercialisation of Agile. My campaign to make of devops a job title isn’t a campaign to come up with a set of bullet points that define Devops as a job so that I can put it on a resume or build it into a product. My argument here is that the guy I’m trying to hire, John, I want him to be a certain kind of guy and the best way I have to describe what I want is Devops Engineer. I’m looking for an operations guy , but I want him to be open to developers, consider engineering and the company as a whole, be focused on delivering value and not rathole into fights about technology or claim root access only on principle. I want that guy to have great communication skills and the interest to explore what’s besides his infrastructure, to be wanting to borrow as much good he can find in other disciplines across the organisation. And then of course there is the practical part, the desire to automate and escape a boring manual routine, the familiarity with cloud that willing or not has powered the movement, and even more specific things like configuration management. You may argue that this is just a good engineer or what systems engineers are becoming, in other words nothing new under the sun. And you may be right, but job titles are in many ways just another way to communicate, to broadcast an intent and a need. So you know what I told John about hiring Devops Engineers? That I felt pretty damn proud about it. The true ones, not the ones slapping it on their CV to get a job, are fantastic engineers and I can’t but encourage them to start to respond to that qualifier. Likewise the companies and individuals seeking them out are likely the ones building great groups those people will want to be members of. Yes, the moment it becomes a keyword recruiters start to match against we’re likely to see a spur of fakes trying to land a job, but that’s nothing new under the sun. Signed, a Devops manager Source: http://www.spikelab.org/devops-job-title/
March 5, 2012
by Spike Morelli
· 10,728 Views
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Why You Shouldn't Use Quartz Scheduler
If you need to schedule jobs in Java, it is fairly common in the industry to use Quartz directly or via Spring integration, but you might want to think twice.
January 30, 2012
by Craig Flichel
· 303,568 Views · 5 Likes
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Diminishing Returns in software development and maintenance
Everyone knows from reading The Mythical Man Month that as you add more people to a software development project you will see diminishing marginal returns. When you add a person to a team, there’s a short-term hit as the rest of the team slows down to bring the new team member up to speed and adjusts to working with another person, making sure that they fit in and can contribute. There’s also a long-term cost. More people means more people who need to talk to each other (n x n-1 / 2), which means more opportunities for misunderstandings and mistakes and misdirections and missed handoffs, more chances for disagreements and conflicts, more bottleneck points. As you continue to add people, the team needs to spend more time getting each new person up to speed and more time keeping everyone on the team in synch. Adding more people means that the team speeds up less and less, while people costs and communications costs and overhead costs keep going up. At some point negative returns set in – if you add more people, the team’s performance will decline and you will get less work done, not more. Diminishing Returns from any One Practice But adding too many people to a project isn’t the only case of diminishing returns in software development. If you work on a big enough project, or if you work in maintenance for long enough, you will run into problems of diminishing returns everywhere that you look. Pushing too hard in one direction, depending too much on any tool or practice, will eventually yield diminishing returns. This applies to: - Manual functional and acceptance testing - Test automation - Any single testing technique - Code reviews - Static analysis bug finding tools - Penetration tests and other security reviews Aiming for 100% code coverage on unit tests is a good example. Building a good automated regression safety net is important – as you wire in tests for key areas of the system, programmers get more confidence and can make more changes faster. How many tests are enough? In Continuous Delivery, Jez Humble and David Farley set 80% coverage as a target for each of automated unit testing, functional testing and acceptance testing. You could get by with lower coverage in many areas, higher coverage in core areas. You need enough tests to catch common and important mistakes. But beyond this point, more tests get more difficult to write, and find fewer problems. Unit testing can only find so many problems in the first place. In Code Complete, Steve McConnell explains that unit testing can only find between 15% and 50% (on average 30%) of the defects in your code. Rather than writing more unit tests, people’s time would be better spent on other approaches like exploratory system testing and code reviews or stress testing or fuzzing to find different kinds of errors. Too much of anything is bad, but too much whiskey is enough. Mark Twain, as quoted in Code Complete Refactoring is important for maintaining and improving the structure and readability of code over time. It is intended to be a supporting practice – to help make changes and fixes simpler and clearer and safer. When refactoring becomes an end in itself or turns into Obsessive Refactoring Disorder, it not only adds unnecessary costs as programmers waste time over trivial details and style issues, it can also add unnecessary risks and create conflict in a team. Make sure that refactoring is done in a disciplined way, and focus refactoring on those areas that need it the most: on code that is frequently changed, routines that are too big, too hard to read, too complex and error-prone. Putting most of your attention refactoring (or if necessary rewriting) this code will get you the highest returns. Less and Less over Time Diminishing returns also set in over time. The longer that you spend working the same way and with the same tools, the less benefits you will see. Even core practices that you’ve grown to depend on don’t pay back over time, and at some point may cost more than they are worth. It’s time again for New Year’s resolutions – time to sign up at a gym and start lifting weights. If you stick with the same routine for a couple of months, you will start to see good results. But after a while your body will get used to the work – if you keep doing the same things the same way your performance will plateau and you will stop seeing gains. You will get bored and stop going to the gym, which will leave more room for people like me. If you do keep going, trying to push harder for returns, you will overtrain and injure yourself. The same thing happens to software teams following the same practices, using the same tools. Some of this is due to inertia. Teams, organizations reach an equilibrium point and they want to stay there. Because it is comfortable, and it works – or at least they understand it. And because the better the team is working, the harder it is to get better – all the low-hanging fruit has been picked. People keep doing what worked for them in the past. They stop looking beyond their established routines, stop looking for new ideas. Competence and control lead to complacency and acceptance. Instead of trying to be as good as possible, they settle for being good enough. This is the point of inspect-and-adapt in Scrum and other time boxed methods – asking the team to regularly re-evaluate what they are doing and how they are doing it, what’s going well and what isn’t, what they should do more of or less of, challenging the status quo and finding new ways to move forward. But even the act of assessing and improving is subject to diminishing returns. If you are building software in 2-week time boxes, and you’ve been doing this for 3, 4 or 5 years, then how much meaningful feedback should you really expect from so many superficial reviews? After a while the team finds themselves going over the same issues and problems and coming up with the same results. Reviews become an unnecessary and empty ritual, another waste of time. The same thing happens with tools. When you first start using a static analysis bug checking tool for example, there’s a good chance that you will find some interesting problems that you didn’t know were in the code – maybe even more problems than you can deal with. But once you triage this and fix up the code and use the tool for a while, the tool will find fewer and fewer problems until it gets to the point where you are paying for insurance – it isn’t finding problems any more, but it might someday. In "Has secure software development reached its limits?” William Jackson argues that SDLCs – all of them – eventually reach a point of diminishing returns from a quality and security standpoint, and that Microsoft and Oracle and other big shops are already seeing diminishing returns from their SDLCs. Their software won’t get any better – all they can do is to keep spending time and money to stay where they are. The same thing happens with Agile methods like Scrum or XP – at some point you’ve squeezed everything that you can from this way or working, and the team’s performance will plateau. What can you do about diminishing returns? First, understand and expect returns to diminish over time. Watch for the signs, and factor this into your expectations – that even if you maintain discipline and keep spending on tools, you will get less and less return for your time and money. Watch for the team’s velocity to plateau or decline. Expect this to happen and be prepared to make changes, even force fundamental changes on the team. If the tools that you are using aren’t giving returns any more, then find new ones, or stop using them and see what happens. Keep reviewing how the team is working, but do these reviews differently: review less often, make the reviews more focused on specific problems, involve different people from inside and outside of the team. Use problems or mistakes as an opportunity to shake things up and challenge the status quo. Dig deep using Root Cause Analysis and challenge the team’s way of thinking and working, look for something better. Don’t settle for simple answers or incremental improvements. Remember the 80/20 rule. Most of your problems will happen in the same small number of areas, from a small number of common causes. And most of your gains will come from a few initiatives. Change the team’s driving focus and key metrics, set new bars. Use Lean methods and Lean Thinking to identify and eliminate bottlenecks, delays and inefficiencies. Look at the controls and tests and checks that you have added over time, question whether you still need them, or find steps and checks that can be combined or automated or simplified. Focus on reducing cycle time and eliminating waste until you have squeezed out what you can. Then change your focus to quality and eliminating bugs, or to simplifying the release and deployment pipeline, or some other new focus that will push the team to improve in a meaningful way. And keep doing this and pushing until you see the team slowing down and results declining. Then start again, and push the team to improve again along another dimension. Keep watching, keep changing, keep moving ahead. Source: http://swreflections.blogspot.com/2011/11/diminishing-returns-in-software.html
December 14, 2011
by Jim Bird
· 13,455 Views
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Zero Downtime – What is it and why is it important?
For most large web applications, uptime is of foremost importants. Any outage can be seen by customers as a frustration, or opportunity to move to a competitor. What's more for a site that also includes e-commerce, it can mean real lost sales. Zero Downtime describes a site without service interruption. To achieve such lofty goals, redundancy becomes a critical requirement at every level of your infrastructure. If you're using cloud hosting, are you redundant to alternate availability zones and regions? Are you using geographically distributed load balancing? Do you have multiple clustered databases on the backend, and multiple webservers load balanced. All of these requirements will increase uptime, but may not bring you close to zero downtime. For that you'll need thorough testing. The solution is to pull the trigger on sections of your infrastructure, and prove that it fails over quickly without noticeable outage. The ultimate test is the outage itself. Sean Hull on Quora: What is zero downtime and why is it important? Source: http://www.iheavy.com/2011/06/23/zero-downtime-what-is-it-and-why-is-it-important/
November 23, 2011
by Sean Hull
· 26,149 Views
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You can’t be Agile in Maintenance?
I’ve been going over a couple of posts by Steve Kilner that question whether Agile methods can be used effectively in software maintenance. It’s a surprising question really. There are a lot of maintenance teams who have had success following Agile methods like Scrum and Extreme Programming (XP) for some time now. We’ve been doing it for almost 5 years, enhancing and maintaining and supporting enterprise systems, and I know that it works. Agile development naturally leads into maintenance – the goal of incremental Agile development is to get working software out to customers as soon as possible, and get customers using it. At some point, when customers are relying on the software to get real business done and need support and help to keep the system running, teams cross from development over to maintenance. But there’s no reason for Agile development teams to fundamentally change the way that they work when this happens. It is harder to introduce Agile practices into a legacy maintenance team – there are a lot of technical requirements and some cultural changes that need to be made. But most maintenance teams have little to lose and lots to gain from borrowing from what Agile development teams are doing. Agile methods are designed to help small teams deal with a lot of change and uncertainty, and to deliver software quickly – all things that are at least as important in maintenance as they are in development. Technical practices in Extreme Programming especially help ensure that the code is always working – which is even more important in maintenance than it is in development, because the code has to work the first time in production. Agile methods have to be adapted to maintenance, but most teams have found it necessary to adapt these methods to fit their situations anyways. Let’s look at what works and what has to be changed to make Agile methods like Scrum and XP work in maintenance. What works well and what doesn’t Planning Game Managing maintenance isn’t the same as managing a development project – even an Agile development project. Although Agile development teams expect to deal with ambiguity and constant change, maintenance teams need to be even more flexible and responsive, to manage conflicts and unpredictable resourcing problems. Work has to be continuously reviewed and prioritized as it comes in – the customer can’t wait for 2 weeks for you to look at a production bug. The team needs a fast path for urgent changes and especially for hot fixes. You have to be prepared for support demands and interruptions. Structure the team so that some people can take care of second-level support, firefighting and emergency bug fixing and the rest of the team can keep moving forward and get something done. Build slack into schedules to allow for last-minute changes and support escalation. You will also have to be more careful in planning out maintenance work, to take into account technical and operational dependencies and constraints and risks. You’re working in the real world now, not the virtual reality of a project. Standups Standups play an important role in Agile projects to help teams come up to speed and bond. But most maintenance teams work fine without standups – since a lot of maintenance work can be done by one person working on their own, team members don’t need to listen to each other each morning talking about what they did yesterday and what they’re going to do – unless the team is working together on major changes. If someone has a question or runs into a problem, they can ask for help without waiting until the next day. Small releases Most changes and fixes that maintenance teams need to make are small, and there is almost always pressure from the business to get the code out as soon as it is ready, so an Agile approach with small and frequent releases makes a lot of sense. If the time boxes are short enough, the customer is less likely to interrupt and re-prioritize work in progress – most businesses can wait a few days or a couple of weeks to get something changed. Time boxing gives teams a way to control and structure their work, an opportunity to batch up related work to reduce development and testing costs, and natural opportunities to add in security controls and reviews and other gates. It also makes maintenance work more like a project, giving the team a chance to set goals and to see something get done. But time boxing comes with overhead – the planning and setup at the start, then deployment and reviews at the end – all of which adds up over time. Maintenance teams need to be ruthless with ceremonies and meetings, pare them down, keep only what’s necessary and what works. It’s even more important in maintenance than in development to remember that the goal is to deliver working code at the end of each time box. If some code is not working, or you’re not sure if it is working, then extend the deadline, back some of the changes out, or pull the plug on this release and start over. Don’t risk a production failure in order to hit an arbitrary deadline. If the team is having problems fitting work into time boxes, then stop and figure out what you’re doing wrong – the team is trying to do too much too fast, or the code is too unstable, or people don’t understand the code enough – and fix it and move on. Reviews and Retrospectives Retrospectives are important in maintenance to keep the team moving forward, to find better ways of working, and to solve problems. But like many practices, regular reviews reach a point of diminishing returns over time – people end up going through the motions. Once the team is setup, reviews don’t need to be done in each iteration unless the team runs into problems. Schedule reviews when you or the team need them. Collect data on how the team is working, on cycle time and bug report/fix ratios, correlate problems in production with changes, and get the team together to review if the numbers move off track. If the team runs into a serious problem like a major production failure, then get to the bottom of it through Root Cause Analysis. Sustainable pace / 40-hour week It’s not always possible to work a 40-hour week in maintenance. There are times when the team will be pushed to make urgent changes, spend late nights firefighting, releasing after hours and testing on weekends. But if this happens too often or goes on too long the team will burn out. It’s critical to establish a sustainable pace over the long term, to treat people fairly and give them a chance to do a good job. Pairing Pairing is hard to do in small teams where people are working on many different things. Pairing does make sense in some cases – people naturally pair-up when trying to debug a nasty problem or walking through a complicated change – but it’s not necessary to force it on people, and there are good reasons not to. Some teams (like mine) rely more on code reviews instead of pairing, or try to get developers to pair when first looking at a problem or change, and at the end again to review the code and tests. The important thing is to ensure that changes get looked at by at least one other person if possible, however this gets done. Collective Code Ownership Because maintenance teams are usually small and have to deal with a lot of different kinds of work, sooner or later different people will end up working on different parts of the code. It’s necessary, and it’s a good thing because people get a chance to learn more about the system and work with different technologies and on different problems. But there’s still a place for specialists in maintenance. You want the people who know the code the best to make emergency fixes or high-risk changes – or at least have them review the changes – because it has to work the first time. And sometimes you have no choice – sometimes there is only one person who understands a framework or language or technical problem well enough to get something done. Coding Guidelines – follow the rules Getting the team to follow coding guidelines is important in maintenance to help ensure the consistency and integrity of the code base over time – and to help ensure software security. Of course teams may have to compromise on coding standards and style conventions, depending on what they have inherited in the code base; and teams that maintain multiple systems will have to follow different guidelines for each system. Metaphor In XP, teams are supposed to share a Metaphor: a simple high-level expression of the system architecture (the system is a production line, or a bill of materials) and common names and patterns that can be used to describe the system. It’s a fuzzy concept at best, a weak substitute for more detailed architecture or design, and it’s not of much practical value in maintenance. Maintenance teams have to work with the architecture and patterns that are already in place in the system. What is important is making sure that the team has a common understanding of these patterns and the basic architecture so that the integrity isn’t lost – if it hasn’t been lost already. Getting the team together and reviewing the architecture, or reverse-engineering it, making sure that they all agree on it and documenting it in a simple way is important especially when taking over maintenance of a new system and when you are planning major changes. Simple Design Agile development teams start with simple designs and try to keep them simple. Maintenance teams have to work with whatever design and architecture that they inherit, which can be overwhelmingly complex, especially in bigger and older systems. But the driving principle should still be to design changes and new features as simple as the existing system lets you – and to simplify the system’s design further whenever you can. Especially when making small changes, simple, just-enough design is good – it means less documentation and less time and less cost. But maintenance teams need to be more risk adverse than development teams – even small mistakes can break compatibility or cause a run-time failure or open a security hole. This means that maintainers can’t be as iterative and free to take chances, and they need to spend more time upfront doing analysis, understanding the existing design and working through dependencies, as well as reviewing and testing their changes for regressions afterwards. Refactoring Refactoring takes on a lot of importance in maintenance. Every time a developer makes a change or fix they should consider how much refactoring work they should do and can do to make the code and design clearer and simpler, and to pay off technical debt. What and how much to refactor depends on what kind of work they are doing (making a well-thought-out isolated change, or doing shotgun surgery, or pushing out an emergency hot fix) and the time and risks involved, how well they understand the code, how good their tools are (development IDEs for Java and .NET at least have good built-in tools that make many refactorings simple and safe) and what kind of safety net they have in place to catch mistakes – automated tests, code reviews, static analysis. Some maintenance teams don’t refactor because they are too afraid of making mistakes. It’s a vicious circle – over time the code will get harder and harder to understand and change, and they will have more reasons to be more afraid. Others claim that a maintenance team is not working correctly if they don’t spend at least 50% of their time refactoring. The real answer is somewhere in between – enough refactoring to make changes and fixes safe. There are cases where extensive refactoring, restructuring or rewriting code is the right thing to do. Some code is too dangerous to change or too full of bugs to leave the way it is – studies show that in most systems, especially big systems, 80% of the bugs can cluster in 20% of the code. Restructuring or rewriting this code can pay off quickly, reducing problems in production, and significantly reducing the time needed to make changes and test them as you go forward. Continuous Testing Testing is even more important and necessary in maintenance than it is in development. And it’s a major part of maintenance costs. Most maintenance teams rely on developers to test their own changes and fixes by hand to make sure that the change worked and that they didn’t break anything as a side effect. Of course this makes testing expensive and inefficient and it limits how much work the team can do. In order to move fast, to make incremental changes and refactoring safe, the team needs a better safety net, by automating unit and functional tests and acceptance tests. It can take a long time to put in test scaffolding and tools and write a good set of automated tests. But even a simple test framework and a small set of core fat tests can pay back quickly in maintenance, because a lot changes (and bugs) tend to be concentrated in the same parts of the code – the same features, framework code and APIs get changed over and over again, and will need to be tested over and over again. You can start small, get these tests running quickly and reliably and get the team to rely on them, fill in the gaps with manual tests and reviews, and then fill out the tests over time. Once you have a basic test framework in place, developers can take advantage of TFD/TDD especially for bug fixes – the fix has to be tested anyways, so why not write the test first and make sure that you fixed what you were supposed to? Continuous Integration To get Continuous Testing to work, you need a Continuous Integration environment. Understanding, automating and streamlining the build and getting the CI server up and running and wiring in tests and static analysis checks and reporting can take a lot of work in an enterprise system, especially if you have to deal with multiple languages and platforms and dependencies between systems. But doing this work is also the foundation for simplifying release and deployment – frequent short releases means that release and deployment has to be made as simple as possible. Onsite Customer / Product Owner Working closely with the customer to make sure that the team is delivering what the customer needs when the customer needs it is as important in maintenance as it is in developing a new system. Getting a talented and committed Customer engaged is hard enough on a high-profile development project – but it’s even harder in maintenance. You may end up with too many customers with conflicting agendas competing for the team’s attention, or nobody who has the time or ability to answer questions and make decisions. Maintenance teams often have to make compromises and help fill in this role on their own. But it doesn’t all fit…. Kilner’s main point of concern isn’t really with Agile methods in maintenance. It’s with incremental design and development in general – that some work doesn’t fit nicely into short time boxes. Short iterations might work ok for bug fixes and small enhancements (they do), but sometimes you need to make bigger changes that have lots of dependencies. He argues that while Agile teams building new systems can stub out incomplete work and keep going in steps, maintenance teams have to get everything working all at once – it’s all or nothing. It’s not easy to see how big changes can be broken down into small steps that can be fit into short time boxes. I agree that this is harder in maintenance because you have to be more careful in understanding and untangling dependencies before you make changes, and you have to be more careful not to break things. The code and design will sometimes fight the kinds of changes that you need to make, because you need to do something that was never anticipated in the original design, or whatever design there was has been lost over time and any kind of change is hard to make. It’s not easy – but teams solve these problems all the time. You can use tools to figure out how much of a dependency mess you have in the code and what kind of changes you need to make to get out of this mess. If you are going to spend “weeks, months, or even years” to make changes to a system, then it makes sense to take time upfront to understand and break down build dependencies and isolate run-time dependencies, and put in test scaffolding and tests to protect the team from making mistakes as they go along. All of this can be done in time boxed steps. Just because you are following time boxes and simple, incremental design doesn’t mean that you start making changes without thinking them through. Read Working With Legacy Code – Michael Feathers walks through how to deal with these problems in detail, in both object oriented and procedural languages. What to do if it takes forever to make a change. How to break dependencies. How to find interception points and pinch points. How to find structure in the design and the code. What tests to write and how to get automated tests to work. Changing data in a production system, especially data shared with other systems, isn’t easy either. You need to plan out API changes and data structure changes as carefully as possible, but you can still make data and database changes in small, structured steps. To make code changes in steps you can use Branching by Abstraction where it makes sense (like making back-end changes) and you can protect customers from changes through Feature Flags and Dark Launching like Facebook and Twitter and Flickr do to continuously roll out changes – although you need to be careful, because if taken too far these practices can make code more fragile and harder to work with. Agile development teams follow incremental design and development to help them discover an optimal solution through trial-and-error. Maintenance teams work this way for a different reason – to manage technical risks by breaking big changes down and making small bets instead of big ones. Working this way means that you have to put in scaffolding (and remember to take it out afterwards) and plan out intermediate steps and review and test everything as you make each change. Sometimes it might feel like you are running in place, that it is taking longer and costing more. But getting there in small steps is much safer, and gives you a lot more control. Teams working on large legacy code bases and old technology platforms will have a harder time taking on these ideas and succeeding with them. But that doesn’t mean that they won’t work. Yes, you can be Agile in maintenance.
October 14, 2011
by Mitch Pronschinske
· 17,525 Views
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The Goal of software development
The Goal by Eli Goldratt is a business book in the form of a novel, where the protagonist must save his factory from closing due to very low productivity. The Goal is not limited to the management of a large organization (not even to for-profit companies): you simply have to define different units of measurement, like goal units instead of making money, the default goal. In fact, from the applications of the Theory of Constraints in our field I think it applies to software development too. What follows is my translation of the themes of The Goal to our field. The Goal is... Mking money, of course. For the ones of you with knowledge in accounting, the original goal is: raising throghput, the amounts of items sold (not produced) in the unit of time. Lowering investment/inventory, all the money tied up in the system in the form of assets that could be sold or products that stay in a warehouse. Lowering operational expense, all the money that we have spent as support and that cannot be recovered. How does these measurements apply to software development? A team does not always have an impact on contract negotiation, so often talking about money is far from everyday reality (kudos to you if you can apply that point of the Agile Manifesto.) The goal for software development can be translated, in my opinion, to: raising the throughput, the amount of features delivered (deployed, not implemented or tested) in the unit of time. You can measure this amount in story points, since feature vary in size. lowering investment/inventory, all the time tied up in the system in the form of undeployed or untested features that clutter the code base. In a minor part, also investment in the form of hardware, but that's by far less important than the team's time. lower operational expense, the time spent by developers every day in order to support the development. Automation is a kind of time investment that will bring more time (and quality) in the future, lowering operational expense. Like for material products, WIP has storage and opportunity costs which goes into the operational expense. Kanban is a tool that tries to reduce WIP in order to foster the two latter points. Throughput accounting This kind of throughput accounting is emphasized in the novel, over the use of cost accounting, where each developer (ehm, factory worker) has to be occupied all the time, even if the work he is doing isn't moving towards the goal: neverending refactoring. Specification of a feature which cannot be implemented until two months are gone, and will have to be rewritten. Implementation of features which won't be merged with the main branch any time soon. With Test-Driven Development, we are getting good at moving a feature from implemented to tested directly in the same commit. Yet the missing step is getting the feature to the users: maybe that's also what Continuous Deployment is all about... Dependent events Dependent events and statistical fluctuations are production systems topics that make a balanced plant close to bankruptcy: however, we're not at the point in which we can model our team as precisely as a factory. The basic point is that a plant in which everyone is working all the time is inefficient: when an early stage (like defining a specification or implementing a feature) gets delayed, downstream step such as deployment are dalayed too. Converely, when an upstream step finish earlier, the downstream stage is already at maximum efficiency and cannot process the intermediate result faster. I wonder if this applies to software development too. In a factory, workers are specialized and can do just a few jobs across the plant. Since workers and machines have different production rates, there will be just one bottleneck: the slowest one. If products have to pass from the bottleneck, anyone producing faster than the bottleneck will just accumulate WIP in front of him. Continuing with our example, if the analyst or domain expert is churning out specifications for new features every day, most of them are just WIP in front of the development team. Once there is an established buffer, any additional specification won't raise throughput any faster; instead, it will raise the inventory (partial features) and the time spent in managing it. I think this is not always true in the most technical phases of development instead. For example, in a small team a developer may be moved to testing or refactoring, or setting up Continuous Integration or evaluation of a new library. Unless you have a DBA which can just manage databases, your developer is not fixed into a stage of the system. The bottleneck The previous example featured a bottleneck, the most famous concept of the Theory of Constraints introduced in the book. This translation to the software development case is mine and could be incomplete. A feature (or a user story) has to pass in a series of stations where different people will work on it to make it real: specification from a domain expert, implementation from a technical team, extended testing with optional customer validation, deployment which should be fast but at the same time must not kill the current version of the application. Each station has an average velocity. By definition, there is a station which is the slowest and can process fewest story points in the unit of time. This is the bottleneck. (This is not always true, as velocity may vary greatly in time with the addition of new people or hidden lines discovered in a feature. Becoming good at estimation and stabilizing a team are two objectives that help reach the assumption.) You can identify a bottleneck by looking at where is the WIP: it will accumulate in front of it. If you already have a kanban board, this phase is simpler... Once identified, the throughput of the system can only be improved by raising the bottleneck's capacity enough so that it is no more a bottleneck. You can move people to it (keeping an eye on communication costs); ensure it is used at maximum efficiency by freeing the specialized developers from other mundane tasks. Now you can restart and find a new bottleneck... Conclusions This is just a little introduction to the themes of the Theory of Constraints and Goldratt's teachings; I don't pretend to explain the whole book in an article. It is also against the Socratic method: you should reach the answers yourself, and these are just examples from my experience. There is more to Goldratt and The Goal than bottlenecks and throughput, such as continuous improvement. If you're working or managing in a software development team, I suggest you to read this book if you have the opportunity. Even when freelancing, it is an eye-opener in moving towards a Goal instead of busyworking; and it's written with a never boring teaching method.
October 4, 2011
by Giorgio Sironi
· 21,672 Views
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EC2 Interview – AWS Interview – Cloud Interview – 8 Questions
If you're looking for a cloud expert, specifically someone who knows Amazon Web Services and EC2, you'll want to have a battery of questions to assess their knowledge.
September 15, 2011
by Sean Hull
· 111,875 Views · 1 Like
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When You Have No Product Owner At All
What happens when you have no product owner at all? How does a team know what features to develop in what order? Several teams I know encountered this. They all had product managers. Most of them had BAs. All of them had a technical manager who was willing to be their product owner, but they had no real product owner. They called themselves Scrum-but. I used to think this was ok. I now think Scrum-but is a bad label. That’s because agile needs a responsible person who is not part of the cross-functional technical team to rank the backlog so the team knows the order of the work. Without that person, the team does not know what to do. So why is it so bad for a team to call itself Scrum-but? Because it’s not Scrum-but. It’s not Scrum. It’s iterative and incremental, but it’s not even close to Scrum. It’s not agile. Johanna's General Agile Picture When you have no product owner who is not outside the team, or outside the hierarchy of the team, you lose something very precious to agility, the notion of the customer or customer surrogate. You lose the person who could be helping the team understand what the customer really wants. You lose the back-and-forth about the product that the customer helps the team understand. The manager can help the team understand the requirements, but the manager is not the customer. The manager is not the person who can set the real acceptance criteria. The manager can see the demo, but the manager cannot say for sure that the team is developing the correct requirements in the correct order. So why am I so insistent that we stop calling this Scrum-but, and even stop calling this agile? Because it breaks down the separation when-and-what-to-build (responsible person responsibility from ongoing incremental delivery of product on a regular basis (the cross-functional team responsibility). The customer or responsible person explains when-to-build in my little picture. The team decides how to build it. When the team manager gets involved, that allows the “business” to be unaccountable for developing the system. How do you know what is shippable product without the responsible person? The problem is this: System development, product development is a joint venture between the business people and the technical people. We need the legal, marketing, sales, and anyone else on the “business” side of the house to help us with the what-and-when to build decisions. That’s why we need a responsible person. In Scrum, that person is called a product owner. And, we need a technical project team to deliver the value. We use agile as an approach and use the demo because it shows business value every iteration. When the business is unaccountable, the agile ecosystem breaks down. We no longer have ideas coming into that funnel, being evaluated by that responsible person. Sure that responsible person has a lot to do. And, that responsible person should develop product roadmaps and make the potential product direction transparent to the rest of the organization. That way, the next iteration or two is clear for the team, and everyone can fight discuss the product direction. But when all the discussion is in the technical organization, those discussions tend to not happen. Or the discussions go off in a different direction than the product needs to go. And, that’s a Very Bad Thing. Because, when the discussions don’t occur, the technical group takes all the responsibility for the product: for what to build, when to build it, and for how to build it. And that means we have let the rest of the business abdicate all of their responsibility for their part of the product. That’s not the partnership agile promises us, nor is the transparency agile promises us. So, when you hear Scrum-but because you have no product owner, substitute “On the road to agile.” You’re actually iterative and incremental, but not agile. You have not made one of the necessary cultural changes for transitioning to agile. Can you keep doing what you are doing? Sure, if it’s working for you. And, that’s the million dollar question: How is this working for you? (If you would like more hints as to what else to do, consider my project management book, Manage It! Your Guide to Modern, Pragmatic Project Management. You have other options, if you cannot manage the agile cultural change right now. Those other options will help you move closer to agile than trying Scrum-but and failing.) This is one of the points—the agile ecosystem and making it succeed—I’m working on for my keynote at the Agile Vancouver conference in late October.
August 25, 2011
by Johanna Rothman
· 7,017 Views
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Watermelon Reporting
This is what Wikipedia writes about the watermelon: The Watermelon (Citrullus lanatus (Thunb.), family Cucurbitaceae) can be both the fruit and the plant of a vine-like (scrambler and trailer) plant originally from southern Africa, and is one of the most common types of melon. [...] The watermelon fruit, loosely considered a type of melon (although not in the genus Cucumis), has a smooth exterior rind (green, yellow and sometimes white) and a juicy, sweet interior flesh (usually pink, but sometimes orange, yellow, red and sometimes green if not ripe). Watermelon (Citrullus lanatus (Thunb.), family Cucurbitaceae) can be both the fruit and the plant of a vine-like (scrambler and trailer) plant originally from southern Africa, and is one of the most common types of melon. This flowering plant produces a special type of fruit known by botanists as a pepo, a berry which has a thick rind (exocarp) and fleshy center (mesocarp and endocarp); pepos are derived from an inferior ovary, and are characteristic of the Cucurbitaceae. The watermelon fruit, loosely considered a type of melon (although not in the genus Cucumis), has a smooth exterior rind (green, yellow and sometimes white) and a juicy, sweet interior flesh (usually pink, but sometimes orange, yellow, red and sometimes green if not ripe). For my metaphor, I’ll use the one with red flesh but orange and yellow would work too. I think most of us experienced the phenomenon when the project status is red but is getting greener and greener when climbing the management ladder. The project’s core is red but for the management it has a nice green paring, so it looks like a watermelon. This is why I call this phenomenon Watermelon Reporting. But why are we creating such reports and how can we avoid it? Why? The bearer of bad news already had a bad time in the ancient world. If he was lucky, they gave him the chop but in other cases they simply chopped his head of. This hasn’t changed until now but fortunately only in a figurative sense. Some bosses aren’t interested that there are problems with a project in their responsibility because if they know about it, they are in charge. So what do they do to avoid incurring the wrath of their boss ? They tweak the project status just a bit and the melon starts growing. Another reason could be that nobody wants to be in the focus of management, thus they embellish the project status in the hope that everything turns for the better. And as we all know hope is the last to die. In the end the result is the same.. Eventually the overripe melon bursts and there is no rescue for the project anymore. How to avoid it? The answer is easy: Transparency, transparency and transparency. If there is no way to hide the current status the watermelon can’t grow. Fortunately Scrum and other agile frameworks provide tools like burndown charts and backlogs to help the team with their transparency. But there are also tools like dashboards or kanban boards to do this job, but this will be the subject of one of my next blog posts. Conclusion The nuts and bolts of any project are transparency. If the project status is transparent, the watermelons can’t arise. If anybody is able to get the information, it will be difficult to hide something.
August 8, 2011
by Marc Löffler
· 9,349 Views
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