In Java, you can easily implement some business logic in Plain Old Java Object (POJO) classes, and then able to run them in a fancy server or framework without much hassle. There many server/frameworks, such as JBossAS, Spring or Camel etc, that would allow you to deploy POJO without even hardcoding to their API. Obviously you would get advance features if you willing to couple to their API specifics, but even if you do, you can keep these to minimal by encapsulating your own POJO and their API in a wrapper. By writing and designing your own application as simple POJO as possible, you will have the most flexible ways in choose a framework or server to deploy and run your application. One effective way to write your business logic in these environments is to use Service component. In this article I will share few things I learned in writing Services. What is a Service? The word Service is overly used today, and it could mean many things to different people. When I say Service, my definition is a software component that has minimal of life-cycles such as init, start, stop, and destroy. You may not need all these stages of life-cycles in every service you write, but you can simply ignore ones that don't apply. When writing large application that intended for long running such as a server component, definining these life-cycles and ensure they are excuted in proper order is crucial! I will be walking you through a Java demo project that I have prepared. It's very basic and it should run as stand-alone. The only dependency it has is the SLF4J logger. If you don't know how to use logger, then simply replace them with System.out.println. However I would strongly encourage you to learn how to use logger effectively during application development though. Also if you want to try out the Spring related demos, then obviously you would need their jars as well. Writing basic POJO service You can quickly define a contract of a Service with life-cycles as below in an interface. package servicedemo; public interface Service { void init(); void start(); void stop(); void destroy(); boolean isInited(); boolean isStarted(); } Developers are free to do what they want in their Service implementation, but you might want to give them an adapter class so that they don't have to re-write same basic logic on each Service. I would provide an abstract service like this: package servicedemo; import java.util.concurrent.atomic.*; import org.slf4j.*; public abstract class AbstractService implements Service { protected Logger logger = LoggerFactory.getLogger(getClass()); protected AtomicBoolean started = new AtomicBoolean(false); protected AtomicBoolean inited = new AtomicBoolean(false); public void init() { if (!inited.get()) { initService(); inited.set(true); logger.debug("{} initialized.", this); } } public void start() { // Init service if it has not done so. if (!inited.get()) { init(); } // Start service now. if (!started.get()) { startService(); started.set(true); logger.debug("{} started.", this); } } public void stop() { if (started.get()) { stopService(); started.set(false); logger.debug("{} stopped.", this); } } public void destroy() { // Stop service if it is still running. if (started.get()) { stop(); } // Destroy service now. if (inited.get()) { destroyService(); inited.set(false); logger.debug("{} destroyed.", this); } } public boolean isStarted() { return started.get(); } public boolean isInited() { return inited.get(); } @Override public String toString() { return getClass().getSimpleName() + "[id=" + System.identityHashCode(this) + "]"; } protected void initService() { } protected void startService() { } protected void stopService() { } protected void destroyService() { } } This abstract class provide the basic of most services needs. It has a logger and states to keep track of the life-cycles. It then delegate new sets of life-cycle methods so subclass can choose to override. Notice that the start() method is checking auto calling init() if it hasn't already done so. Same is done in destroy() method to the stop() method. This is important if we're to use it in a container that only have two stages life-cycles invocation. In this case, we can simply invoke start() and destroy() to match to our service's life-cycles. Some frameworks might go even further and create separate interfaces for each stage of the life-cycles, such as InitableService or StartableService etc. But I think that would be too much in a typical app. In most of the cases, you want something simple, so I like it just one interface. User may choose to ignore methods they don't want, or simply use an adaptor class. Before we end this section, I would throw in a silly Hello world service that can be used in our demo later. package servicedemo; public class HelloService extends AbstractService { public void initService() { logger.info(this + " inited."); } public void startService() { logger.info(this + " started."); } public void stopService() { logger.info(this + " stopped."); } public void destroyService() { logger.info(this + " destroyed."); } } Managing multiple POJO Services with a container Now we have the basic of Service definition defined, your development team may start writing business logic code! Before long, you will have a library of your own services to re-use. To be able group and control these services into an effetive way, we want also provide a container to manage them. The idea is that we typically want to control and manage multiple services with a container as a group in a higher level. Here is a simple implementation for you to get started: package servicedemo; import java.util.*; public class ServiceContainer extends AbstractService { private List services = new ArrayList(); public void setServices(List services) { this.services = services; } public void addService(Service service) { this.services.add(service); } public void initService() { logger.debug("Initializing " + this + " with " + services.size() + " services."); for (Service service : services) { logger.debug("Initializing " + service); service.init(); } logger.info(this + " inited."); } public void startService() { logger.debug("Starting " + this + " with " + services.size() + " services."); for (Service service : services) { logger.debug("Starting " + service); service.start(); } logger.info(this + " started."); } public void stopService() { int size = services.size(); logger.debug("Stopping " + this + " with " + size + " services in reverse order."); for (int i = size - 1; i >= 0; i--) { Service service = services.get(i); logger.debug("Stopping " + service); service.stop(); } logger.info(this + " stopped."); } public void destroyService() { int size = services.size(); logger.debug("Destroying " + this + " with " + size + " services in reverse order."); for (int i = size - 1; i >= 0; i--) { Service service = services.get(i); logger.debug("Destroying " + service); service.destroy(); } logger.info(this + " destroyed."); } } From above code, you will notice few important things: We extends the AbstractService, so a container is a service itself. We would invoke all service's life-cycles before moving to next. No services will start unless all others are inited. We should stop and destroy services in reverse order for most general use cases. The above container implementation is simple and run in synchronized fashion. This mean, you start container, then all services will start in order you added them. Stop should be same but in reverse order. I also hope you would able to see that there is plenty of room for you to improve this container as well. For example, you may add thread pool to control the execution of the services in asynchronized fashion. Running POJO Services Running services with a simple runner program. In the simplest form, we can run our POJO services on our own without any fancy server or frameworks. Java programs start its life from a static main method, so we surely can invoke init and start of our services in there. But we also need to address the stop and destroy life-cycles when user shuts down the program (usually by hitting CTRL+C.) For this, the Java has the java.lang.Runtime#addShutdownHook() facility. You can create a simple stand-alone server to bootstrap Service like this: package servicedemo; import org.slf4j.*; public class ServiceRunner { private static Logger logger = LoggerFactory.getLogger(ServiceRunner.class); public static void main(String[] args) { ServiceRunner main = new ServiceRunner(); main.run(args); } public void run(String[] args) { if (args.length < 1) throw new RuntimeException("Missing service class name as argument."); String serviceClassName = args[0]; try { logger.debug("Creating " + serviceClassName); Class serviceClass = Class.forName(serviceClassName); if (!Service.class.isAssignableFrom(serviceClass)) { throw new RuntimeException("Service class " + serviceClassName + " did not implements " + Service.class.getName()); } Object serviceObject = serviceClass.newInstance(); Service service = (Service)serviceObject; registerShutdownHook(service); logger.debug("Starting service " + service); service.init(); service.start(); logger.info(service + " started."); synchronized(this) { this.wait(); } } catch (Exception e) { throw new RuntimeException("Failed to create and run " + serviceClassName, e); } } private void registerShutdownHook(final Service service) { Runtime.getRuntime().addShutdownHook(new Thread() { public void run() { logger.debug("Stopping service " + service); service.stop(); service.destroy(); logger.info(service + " stopped."); } }); } } With abover runner, you should able to run it with this command: $ java demo.ServiceRunner servicedemo.HelloService Look carefully, and you'll see that you have many options to run multiple services with above runner. Let me highlight couple: Improve above runner directly and make all args for each new service class name, instead of just first element. Or write a MultiLoaderService that will load multiple services you want. You may control argument passing using System Properties. Can you think of other ways to improve this runner? Running services with Spring The Spring framework is an IoC container, and it's well known to be easy to work POJO, and Spring lets you wire your application together. This would be a perfect fit to use in our POJO services. However, with all the features Spring brings, it missed a easy to use, out of box main program to bootstrap spring config xml context files. But with what we built so far, this is actually an easy thing to do. Let's write one of our POJO Service to bootstrap a spring context file. package servicedemo; import org.springframework.context.ConfigurableApplicationContext; import org.springframework.context.support.FileSystemXmlApplicationContext; public class SpringService extends AbstractService { private ConfigurableApplicationContext springContext; public void startService() { String springConfig = System.getProperty("springContext", "spring.xml); springContext = new FileSystemXmlApplicationContext(springConfig); logger.info(this + " started."); } public void stopService() { springContext.close(); logger.info(this + " stopped."); } } With that simple SpringService you can run and load any spring xml file. For example try this: $ java -DspringContext=config/service-demo-spring.xml demo.ServiceRunner servicedemo.SpringService Inside the config/service-demo-spring.xml file, you can easily create our container that hosts one or more service in Spring beans. Notice that I only need to setup init-method and destroy-method once on the serviceContainer bean. You can then add one or more other service such as the helloService as much as you want. They will all be started, managed, and then shutdown when you close the Spring context. Note that Spring context container did not explicitly have the same life-cycles as our services. The Spring context will automatically instanciate all your dependency beans, and then invoke all beans who's init-method is set. All that is done inside the constructor of FileSystemXmlApplicationContext. No explicit init method is called from user. However at the end, during stop of the service, Spring provide the springContext#close() to clean things up. Again, they do not differentiate stop from destroy. Because of this, we must merge our init and start into Spring's init state, and then merge stop and destroy into Spring's close state. Recall our AbstractService#destory will auto invoke stop if it hasn't already done so. So this is trick that we need to understand in order to use Spring effectively. Running services with JEE app server In a corporate env, we usually do not have the freedom to run what we want as a stand-alone program. Instead they usually have some infrustructure and stricter standard technology stack in place already, such as using a JEE application server. In these situation, the most portable way to run POJO services is in a war web application. In a Servlet web application, you can write a class that implements javax.servlet.ServletContextListener and this will provide you the life-cycles hook via contextInitialized and contextDestroyed. In there, you can instanciate your ServiceContainer object and call start and destroy methods accordingly. Here is an example that you can explore: package servicedemo; import java.util.*; import javax.servlet.*; public class ServiceContainerListener implements ServletContextListener { private static Logger logger = LoggerFactory.getLogger(ServiceContainerListener.class); private ServiceContainer serviceContainer; public void contextInitialized(ServletContextEvent sce) { serviceContainer = new ServiceContainer(); List services = createServices(); serviceContainer.setServices(services); serviceContainer.start(); logger.info(serviceContainer + " started in web application."); } public void contextDestroyed(ServletContextEvent sce) { serviceContainer.destroy(); logger.info(serviceContainer + " destroyed in web application."); } private List createServices() { List result = new ArrayList(); // populate services here. return result; } } You may configure above in the WEB-INF/web.xml like this: servicedemo.ServiceContainerListener The demo provided a placeholder that you must add your services in code. But you can easily make that configurable using the web.xml for context parameters. If you were to use Spring inside a Servlet container, you may directly use their org.springframework.web.context.ContextLoaderListener class that does pretty much same as above, except they allow you to specify their xml configuration file using the contextConfigLocation context parameter. That's how a typical Spring MVC based application is configure. Once you have this setup, you can experiment our POJO service just as the Spring xml sample given above to test things out. You should see our service in action by your logger output. PS: Actually what we described here are simply related to Servlet web application, and not JEE specific. So you can use Tomcat server just fine as well. The importance of Service's life-cycles and it's real world usage All the information I presented here are not novelty, nor a killer design pattern. In fact they have been used in many popular open source projects. However, in my past experience at work, folks always manage to make these extremely complicated, and worse case is that they completely disregard the importance of life-cycles when writing services. It's true that not everything you going to write needs to be fitted into a service, but if you find the need, please do pay attention to them, and take good care that they do invoked properly. The last thing you want is to exit JVM without clean up in services that you allocated precious resources for. These would become more disastrous if you allow your application to be dynamically reloaded during deployment without exiting JVM, in which will lead to system resources leakage. The above Service practice has been put into use in the TimeMachine project. In fact, if you look at the timemachine.scheduler.service.SchedulerEngine, it would just be a container of many services running together. And that's how user can extend the scheduler functionalities as well, by writing a Service. You can load these services dynamically by a simple properties file.

these days i’m playing with backbone and using public api as a source. the web browser has one horrible feature: it don’t allow you to fetch any external resource to our host due to the cross-origin restriction. for example if we have a server at localhost we cannot perform one ajax request to another host different than localhost. nowadays there is a header to allow it: access-control-allow-origin . the problem is that the remote server must set up this header. for example i was playing with github’s api and github doesn’t have this header. if the server is my server, is pretty straightforward to put this header but obviously i’m not the sysadmin of github, so i cannot do it. what the solution? one possible solution is, for example, create a proxy server at localhost with php. with php we can use any remote api with curl (i wrote about it here and here for example). it’s not difficult, but i asked myself: can we create a dummy proxy server with php to handle any request to localhost and redirects to the real server, instead of create one proxy for each request?. let’s start. problably there is one open source solution (tell me if you know it) but i’m on holidays and i want to code a little bit (i now, it looks insane but that’s me ). the idea is: ... $proxy->register('github', 'https://api.github.com'); ... and when i type: http://localhost/github/users/gonzalo123 and create a proxy to : https://api.github.com/users/gonzalo123 the request method is also important. if we create a post request to localhost we want a post request to github too. this time we’re not going to reinvent the wheel, so we will use symfony componets so we will use composer to start our project: we create a conposer.json file with the dependencies: { "require": { "symfony/class-loader":"dev-master", "symfony/http-foundation":"dev-master" } } now php composer.phar install and we can start coding. the script will look like this: register('github', 'https://api.github.com'); $proxy->run(); foreach($proxy->getheaders() as $header) { header($header); } echo $proxy->getcontent(); as we can see we can register as many servers as we want. in this example we only register github. the application only has two classes: restproxy , who extracts the information from the request object and calls to the real server through curlwrapper . request = $request; $this->curl = $curl; } public function register($name, $url) { $this->map[$name] = $url; } public function run() { foreach ($this->map as $name => $mapurl) { return $this->dispatch($name, $mapurl); } } private function dispatch($name, $mapurl) { $url = $this->request->getpathinfo(); if (strpos($url, $name) == 1) { $url = $mapurl . str_replace("/{$name}", null, $url); $querystring = $this->request->getquerystring(); switch ($this->request->getmethod()) { case 'get': $this->content = $this->curl->doget($url, $querystring); break; case 'post': $this->content = $this->curl->dopost($url, $querystring); break; case 'delete': $this->content = $this->curl->dodelete($url, $querystring); break; case 'put': $this->content = $this->curl->doput($url, $querystring); break; } $this->headers = $this->curl->getheaders(); } } public function getheaders() { return $this->headers; } public function getcontent() { return $this->content; } } the restproxy receive two instances in the constructor via dependency injection (curlwrapper and request). this architecture helps a lot in the tests , because we can mock both instances. very helpfully when building restproxy. the restproxy is registerd within packaist so we can install it using composer installer: first install componser curl -s https://getcomposer.org/installer | php and create a new project: php composer.phar create-project gonzalo123/rest-proxy proxy if we are using php5.4 (if not, what are you waiting for?) we can run the build-in server cd proxy php -s localhost:8888 -t www/ now we only need to open a web browser and type: http://localhost:8888/github/users/gonzalo123 the library is very minimal (it’s enough for my experiment) and it does’t allow authorization. of course full code is available in github .

First, read this. Why passwords have never been weaker—and crackers have never been stronger. There are numerous important lessons in this article. One of the small lessons is that changing your password every sixty or ninety days is farcical. The rainbow table algorithms can crack a badly-done password in minutes. Every 60 days, the cracker has to spend a few minutes breaking your new password. Why bother changing it? It only annoys the haxorz; they'll be using your account within a few minutes. However. That practice is now so ingrained that it's difficult to dislodge from the heads of security consultants. The big lesson, however, is profound. Work Experience Recently, I got a request from a developer on how to encrypt a password. We have a Python back-end and the developer was asking which crypto package to download and how to install it. "Crypto?" I asked. "Why do we need crypto?" "To encrypt passwords," they replied. I spat coffee on my monitor. I felt like hitting Caps Lock in the chat window so I could respond like this: "NEVER ENCRYPT A PASSWORD, YOU DOLT." I didn't, but I felt like it. Much Confusion The conversation took hours. Chat can be slow that way. Also, I can be slow because I need to understand what's going on before I reply. I'm a slow thinker. But the developer also needed to try stuff and provide concrete code examples, which takes time. At the time, I knew that passwords must be hashed with salt. I hadn't read the Ars Technica article cited above, so I didn't know why computationally intensive hash algorithms are best for this. We had to discuss hash algorithms. We had to discuss algorithms for generating unique salt. We had to discuss random number generators and how to use an entropy source for a seed. We had to discuss http://www.ietf.org/rfc/rfc2617.txt in some depth, since the algorithms in section 3.2.2. show some best practices in creating hash summaries of usernames, passwords, and realms. All of this was, of course, side topics before we got to the heart of the matter. What's Been Going On After several hours, my "why" questions started revealing things. The specific user story, for example, was slow to surface. Why? Partly because I didn't demand it early enough. But also, many technology folks will conceive of a "solution" and pursue that technical concept no matter how difficult or bizarre. In some cases, the concept doesn't really solve the problem. I call this the "Rat Holes of Lost Time" phenomena: we chase some concept through numerous little rat-holes before we realize there's a lot of activity but no tangible progress. There's a perceptual narrowing that occurs when we focus on the technology. Often, we're not actually solving the problem. IT people leap past the problem into the solution as naturally as they breathe. It's a hard habit to break. It turned out that they were creating some additional RESTful web services. They knew that the RESTful requests needed proper authentication. But, they were vague on the details of how to secure the new RESTful services. So they were chasing down their concept: encrypt a password and provide this encrypted password with each request. They were half right, here. A secure "token" is required. But an encrypted password is a terrible token. Use The Framework, Luke What's most disturbing about this is the developer's blind spot. For some reason, the existence of other web services didn't enter into this developer's head. Why didn't they read the code for the services created on earlier sprints? We're using Django. We already have a RESTful web services framework with a complete (and high quality) security implementation. Nothing more is required. Use the RESTful authentication already part of Django. In most cases, HTTPS is used to encrypt at the socket layer. This means that Basic Authentication is all that's required. This is a huge simplification, since all the RESTful frameworks already offer this. The Django Rest Framework has a nice authentication module. When using Piston, it's easy to work with their Authentication handler. It's possible to make RESTful requests with Digest Authentication, if SSL is not being used. For example, Akoha handles this. It's easy to extend a framework to add Digest in addition to Basic authentication. For other customers, I created an authentication handler between Piston and ForgeRock OpenAM so that OpenAM tokens were used with each RESTful request. (This requires some care to create a solution that is testable.) Bottom Lines Don't encrypt passwords. Ever. Don't write your own hash and salt algorithm. Use a framework that offers this to you. Read the Ars Technica article before doing anything password-related.

Today I learned a neat trick to organize imports in Eclipse. Of course, one can use Ctrl + Shift + O to remove the unused imports at file level. But what if you want to remove the unused imports for several files, may be at package level? Simple – in the Package Explorer window, right click on the package that you want to modify and then select source -> Organize Imports which will analyse all the files inside that package and then remove the unused imports. One more nifty trick is that you can automatically organize the imports when you save the file. To enable this, go to Windows -> Preferences -> Java -> Editor -> Save Actions and then enable Perform the selected action on save -> Organize imports. After this, whenever you save a java file, eclipse will remove the unused imports automatically.

The more I use dependency injection (DI) in my code, the more it alters the way I see both my design and implementation. Injection is so convenient and powerful that you end up wanting to make sure you use it as often as you can. And as it turns out, you can use it in many, many places. Let’s cover briefly the most obvious scenarios where DI, and more specifically, Guice, are a good fit: objects created either at class loading time or very early in your application. These two aspects are covered by either direct injection or by providers, which allow you to start building some of your object graph before you can inject more objects. I won’t go too much in details about these two use cases since they are explained in pretty much any Guice tutorial you can find on the net. Once the injector has created your graph of objects, you are pretty much back to normal and instantiating your “runtime objects” (the objects you create during the life time of your application) the normal way, most likely with “new” or factories. However, you will quickly start noticing that you need some runtime information to create these objects, other parts of them could be injected. Let’s take the following example: we have a GeoService interface that provides various geolocation functions, such as telling you if two addresses are close to each other: public interface GeoService { /** * @return true if the two addresses are within @param{miles} * miles of each other. */ boolean isNear(Address address1, Address address2, int miles); } Then you have a Person class which uses this service and also needs a name and an address to be instantiated: public class Person { // Fields omitted public Person(String name, Address address, GeoService gs) { this.name = name; this.address = address; this.geoService = gs; } public boolean livesNear(Person otherPerson) { return geoService.isNear(address, otherPerson.getAddress(), 2 /* miles */); } } Something odd should jump at you right away with this class: while name and address are part of the identity of a Person object, the presence of the GeoService instance in it feels wrong. The service is a singleton that is created on start up, so a perfect candidate to be injected, but how can I achieve the creation of a Person object when some of its information is supplied by Guice and the other part by myself? Guice gives you a very elegant and flexible way to implement this scenario with “assisted injection”. The first step is to define a factory for our objects that represents exactly how we want to create them: public interface PersonFactory { Person create(String name, Address address); } Since only name and address participate in the identity of our Person objects, these are the only parameters we need to construct our objects. The other parameters should be supplied by Guice so we modify our Person constructor to let Guice know: @Inject public Person(@Assisted String name, @Assisted Address address, GeoService geoService) { this.name = name; this.address = address; this.geoService = geoService; } In this code, I have added an @Inject annotation on the constructor and an @Assisted annotation on each parameter that I will be providing. Guice will take care of injecting the rest. Finally, we connect the factory to its objects when creating the module: Module module1 = new FactoryModuleBuilder() .build(PersonFactory.class); The important part here is to realize that we will never instantiate PersonFactory: Guice will. From now on, all we need to do whenever we want to instantiate a Person object is to ask Guice to hand us a factory: @Inject private PersonFactory personFactory; // ... Person p = personFactory.create("Bob", new Address("1 Ocean st")); If you want to find out more, take a look at the main documentation for assisted injection, which explains how to support overloaded constructors and also how to create different kinds of objects within the same factory. Wrapping up Let’s take a look at what we did. First, we started with a suspicious looking constructor: public Person(String name, Address address, GeoService s) { This constructor is suspicious because it accepts parameters that do not participate in the identity of the object (you won’t use the GeoService parameter when calculating the hash code of a Person object). Instead, we replaced this constructor with a factory that only accepts identity fields: public interface PersonFactory { Person create(String name, Address address); } and we let Guice’s assisted injection take care of creating a fully formed object for us. This observation leads us to the Identity Constructor rule: If a constructor accepts parameters that are not used to define the identity of the objects, consider injecting these parameters. Once you start looking at your objects with this rule in mind, you will be surprised to find out how many of them can benefit from assisted injection.

We are proud to announce that the newest major release of our Eclipse-based developer tooling is now available. This is a major release not only in terms of new features but because of other serious changes like project componentization, open-sourcing and the fact that for the first time we are making multiple distributions available, each tailored for a different kind of developer. Check out the release announcement on Martin Lippert's Blog. 100% Open Sourced – All STS features that were previously under a free commercial license, have been donated under the Eclipse Public License (EPL) at GitHub! Intelligent Repackaging - Repackaging the product itself makes identifying what tools you need, and getting started with them much easier. In the past, Groovy/Grails developers had to install several extensions manually into Eclipse to get started. Now there are two full eclipse distributions, one targeted at Spring developers, the other at Groovy/Grails developers – just download, install and go, no assembly required. Componentized projects: Componentizing allows installation and configuration flexibility – developers can install components individually into their existing, plain Eclipse Java EE installations if they wish, preserving their hard work of configuring their Eclipse IDEs just the way they like them. Downloads, more information and FAQ You can find the downloads as well as more information on the project websites for the toolsuites: Spring Tool Suite Groovy/Grails Tool Suite Installation Instructions FAQ Feedback and discussions If you have feedback or questions for us, please do not hesitate to contact us via our SpringSource Tool Suite forum. Bugs and feature requests are always welcome as tickets in our JIRA or, even better, as pull requests on GitHub.

Learn about pros, cons, and basics of Spring security and data, plus Envers integration.

DrupalCon Munich is next week, and I am lucky enough to be going. As part of preparing for the conference, I thought it would be worthwhile to see just how easy (or difficult) it would be to migrate an existing Drupal site to Windows Azure Web Sites. So, in this post, I’ll do just that. Fortunately, because Windows Azure Web Sites supports both PHP and MySQL, the migration process is relatively straightforward. And, because Drupal and PHP run on any platform, the process I’ll describe should work for moving Drupal to Windows Azure Web Sites regardless of what platform you are moving from. Of course, Drupal installations can vary widely, so YMMV. I tested the instructions below on relatively small (and simple) Drupal installation running on CentOS 5. (Unfortunately, I won’t be using Drush since it isn’t supported on Windows Azure Websites.) If you are considering moving a large and complex Drupal application, may want to consider moving to Windows Azure Cloud Services (more information about that here: Migrating a Drupal Site from LAMP to Windows Azure). Before getting started, it’s worth noting that Windows Azure Websites lets you run up to 10 Web Sites for free in a multitenant environment. And, you can seamlessly upgrade to private, reserved VM instances as your traffic grows. To sign up, try the Windows Azure 90-day free trial. 1. Create a Windows Azure Web Site and MySQL database There is a step-by-step tutorial on http://www.windowsazure.com that walks you through creating a new website and a MySQL database, so I’ll refer you there to get started: Create a PHP-MySQL Windows Azure web site and deploy using Git. If you intend to use Git to publish your Drupal site, then go ahead and follow the instructions for setting up a Git repository. Make sure to follow the instructions in the Get remote MySQL connection information section as you will need that information later. You can ignore the remainder of the tutorial for the purposes of deploying your Drupal site, but if you are new to Windows Azure Web Sites (and to Git), you might find the additional reading informative. Ok, now you have a new website with a MySQL database, your have your MySQL database connection information, and you have (optionally) created a remote Git repository and made note of the Git deployment instructions. Now you are ready to copy your database to MySQL in Windows Azure Web Sites. 2. Copy database to MySQL in Windows Azure Web Sites I’m sure there is more than one way to copy your Drupal database, but I found the mysqldump tool to be effective and easy to use. To copy from a local machine to Windows Azure Web Sites, here’s the command I used: mysqldump -u local_username --password=local_password drupal | mysql -h remote_host -u remote_username --password=remote_password remote_db_name You will, of course, have to provide the username and password for your existing Drupal database, and you will have to provide the hostname, username, password, and database name for the MySQL database you created in step 1. This information is available in the connection string information that you should have noted in step 1. i.e. You should have a connection string that looks something like this: Database=remote_db_name;Data Source=remote_host;User Id=remote_username;Password=remote_password Depending on the size of your database, the copying process could take several minutes. Now your Drupal database is live in Windows Azure Websites. Before you deploy your Drupal code, you need to modify it so it can connect to the new database. 3. Modify database connection info in settings.php Here, you will again need your new database connection information. Open the /drupal/sites/default/setting.php file in your favorite text editor, and replace the values of ‘database’, ‘username’, ‘password’, and ‘host’ in the $databases array with the correct values for your new database. When you are finished, you should have something similar to this: $databases = array ( 'default' => array ( 'default' => array ( 'database' => 'remote_db_name', 'username' => 'remote_username', 'password' => 'remote_password', 'host' => 'remote_host', 'port' => '', 'driver' => 'mysql', 'prefix' => '', ), ), ); Be sure to save the settings.phpfile, then you are ready to deploy. 4. Deploy Drupal code using Git or FTP The last step is to deploy your code to Windows Azure Web Sites using Git or FTP. If you are using FTP, you can get the FTP hostname and username from you website’s dashboard. Then, use your favorite FTP client to upload your Drupal files to the /site/wwwroot folder of the remote site. If you are using Git, you need to set up a Git repository in Windows Azure Web Sites (steps for this are in the tutorial mentioned earlier). And, you will need Git installed on your local machine. Then, just follow the instructions provided after you created the repository: One note about using Git here: depending on your Git settings, your .gitignore file (a hidden file and a sibling to the .git folder created in your local root directory after you executed git commit), some files in your Drupal application may be ignored. In my case, all the files in the sites directory were ignored. If this happens, you will want to edit the .gitignore file so that these files aren’t ignored and redeploy. After you have deployed Drupal to Windows Azure Web Sites, you can continue to deploy updates via Git or FTP. Related information If you are looking for more information about Windows Azure Web Sites, these posts might be helpful: Windows Azure Websites- A PHP Perspective Windows Azure Websites, Web Roles, and VMs- When to use which- Configuring PHP in Windows Azure Websites with .user.ini Files One last thing you might consider, depending on your site, is using the Windows Azure Integration Module to store and serve your site’s media files.

In my post about JaCoCo and MavenI wrote about the problems of using the JaCoCo Maven plugin in multimodule Maven projects because of having one report for each module separately instead of one report for all modules, and how it can be fixed using JaCoCo Ant Task. In this post we are going to see how to use the JaCoCo Jenkins plugin to achieve the same goal of Ant Tasks and have overall code coverage statistics for all modules. The first step is installing the JaCoCo Jenkins plugin. Go to Jenkins -> Manage Jenkins -> Plugin Manager -> Available and find JaCoCo Plugin The next step, if it is not done already, is configuring your JaCoCo Maven plugin into parent pom: org.jacoco jacoco-maven-plugin ${jacoco.version} prepare-agent report prepare-package report And finally a post-action must be configured to the job responsible for packaging the application. Note that in previous pom file reports are generated just before the package goal is executed. Go to Configure -> Post-build Actions -> Add post-build action -> Record JaCoCo coverage report. Then we have to set folders or files containing JaCoCoXML reports, which are using the previous pom to **/target/site/jacoco/jacoco*.xml, and also set when we consider that a build is healthy in terms of coverage. Then we can save the job configuration and run the build project. After the project is build, a new report will appear just under the test result trend graph, called code coverage trend, where we can see the code coverage of all project modules. From the left menu, you can enter into Coverage Report and see code coverage of each module separately. Furthermore, visiting the Jenkins main page will give you a nice quick overview of a job when you mouse over the weather icon as shown: Keep in mind that this approach for merging code coverage files will only work if you are using Jenkins as a CI system. Ant Task is a more generic solution and can also be used with the JaCoCo Jenkins plugin. We Keep Learning, Alex.

This is the second article of the series on Spring Integration. This article builds on top of the first article where we introduced Spring Integration. Context setting In the first article, we created a simple java application where A message was sent over a channel, It was intercepted by a service i.e. POJO and modified. It was then sent over a different channel The modified message was read from the channel and displayed. However, in doing this - keeping in mind that we were merely introducing the concepts there - we wrote some Spring specific code in our application i.e. the test classes. In this article we will take care of that and make our application code as insulated from Spring Integration api as possible. This is done by, what Spring Integration calls gateways. Gateways exist for the sole purpose of abstracting messaging related "plumbing" code away from "business" code. The business logic might really not care whether a functionality is being achieved be sending a message over a channel or by making a SOAP call. This abstraction - though logical and desirable - have not been very practical, till now. It is probably worth having a quick look at the Spring Integration Reference Manual at this point. However, if you are just getting started with Spring Integration, you are perhaps better off following this article for the moment. I would recommend you get your hands dirty before returning to reference manual, which is very good but also very exhaustive and hence could be overwhelming for a beginner. The gateway could be a POJO with annotations (which is convenient but in my mind beats the whole purpose) or with XML configurations (can very quickly turn into a nightmare in any decent sized application if unchecked). At the end of the day it is really your choice but I like to go the XML route. The configuration options for both styles are detailed out in this section of the reference implementation. Spring Integration with Gateways So, let's create another test with gateway throw in for our HelloWorld service (refer to the first article of this series for more context). Let's start with the Spring configuration for the test. File: src/test/resources/org/academy/integration/HelloWorld1Test-context.xml In this case, all that is different is that we have added a gateway. This is an interface called org.academy.integration.Greetings. It interacts with both "inputChannel" and "outputChannel", to send and read messages respectively. Let's write the interface. File: /src/main/java/org/academy/integration/Greetings.java package org.academy.integration; public interface Greetings { public void send(String message); public String receive(); } And then we add the implementation of this interface. Wait. There is no implementation. And we do not need any implementation. Spring uses something called GatewayProxyFactoryBean to inject some basic code to this gateway which allows it to read the simple string based message, without us needing to do anything at all. That's right. Nothing at all. Note - You will need to add more code for most of your production scenarios - assuming you are not using Spring Integration framework to just push around strings. So, don't get used to free lunches. But, while it is here, let's dig in. Now, lets write a new test class using the gateway (and not interact with the channels and messages at all). File: /src/test/java/org/academy/integration/HelloWorld1Test.java package org.academy.integration; import static org.junit.Assert.*; import org.junit.Test; import org.junit.runner.RunWith; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.test.context.ContextConfiguration; import org.springframework.test.context.junit4.SpringJUnit4ClassRunner; @RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration public class HelloWorld1Test { private final static Logger logger = LoggerFactory .getLogger(HelloWorld1Test.class); @Autowired Greetings greetings; @Test public void test() { greetings.send("World"); assertEquals(greetings.receive(), "Hello World"); logger.debug("Spring Integration with gateways."); } } Our test class is much cleaner now. It does not know about channels, or messages or anything related to Spring Integration at all. It only knows about a greetings instance - to which it gave some data by .send() method - and got modified data back by .receive() method. Hence, the business logic is oblivious of the plumbing logic, making for a much cleaner code. Now, simply type "mvn -e clean install" (or use m2e plugin) and you should be able to run the unit test and confirm that given string "World" the HelloWorld service indeed returns "Hello World" over the entire arrangement of channels and messages. Again, something optional but I highly recommend, is to run "mvn -e clean install site". This - assuming you have correctly configured some code coverage tool (cobertura in my case) will give you a nice HTML report showing the code coverage. In this case it would be 100%. I have blogged a series on code quality which deals this subject in more detail, but to cut long story short, it is very important for me to ensure that whatever coding practice / framework I use and recommend use, complies to some basic code quality standards. Being able to unit test and measure that is one such fundamental check that I do. Needless to say, Spring in general (including Spring integration) passes that check with flying colours. Conclusion That's it for this article. Happy coding.

I (https://github.com/kelemen) have been (and I still do) use Maven for development of Java code. My main reason for using Maven for development is its great NetBeans IDE support, so that I don't need to maintain IDE project files separately. As much as I like this support in the Maven world, I feel the limits of Maven every day I use it. Since I first saw the Gradle project, I knew that this is the least that I've always wanted from a build tool. So I started to look for NetBeans IDE support for Gradle. To my sadness there is only support for Eclipse and Idea. Aside from the fact that I prefer to use NetBeans IDE, I felt the IDE support to be limited for Gradle, (although the last time I read about Gradle support in IDEA, it seemed promising). Not long ago, I came across Geertjan's plugin and I felt that that writing such plugin is possible without enormous effort. So I downloaded his sources and started to analyze them and rewrite the plugin, so that it works with most Gradle scripts. There are many new features available in my version, such as these: slow tasks are done in a background thread source paths are retrieved from the model "test single" Screenshots: Project menus: Project dependencies: Project debug test: However, I removed subprojects and now each project needs to be opened manually, it is more efficient if you don't plan to edit all the subprojects; the drawback is that you cannot open projects without a build.gradle. The main problem with Gradle daemon performance is that on the first project load, Gradle downloads every single dependency. After that, I found the performance acceptable (especially after I implemented caching of already loaded projects). I have tested it with a relatively large project (>60 subprojects, lots of Java code): It took me about 2 minutes to load the project which seems ok to me for such an enormous project. Other than the project loading, the performance depends on NetBeans which is good. How to try it There is currently no compiled version of the plugin, so you have to compile it for yourself, if you want to try it. You can clone/download the sources from here: https://github.com/kelemen/netbeans-gradle-project After downloading the sources, open the project in NetBeans IDE. There generally two approaches you could consider: Generate the .nbm file (by choosing "Create NBM" in the project's popup) and install the plugin as you would do with any other third-party plugin. "Run" the project. This is the safest thing to do because this will start a new NetBeans instance with a brand new user directory (in the build folder). This way your own NetBeans installation will be unaffected. Help I would appreciate I'm pretty new to the NetBeans APIs (i.e., this is my first time using them), so someone might help me with the project dependencies (possibly Mavenize the plugin). And if it is possible, allow for the plugin to rely on a user specified installation of Gradle (there is some risk in it because Gradle does not seem to be very backward compatible). If you happen to know the Project API in NetBeans well, that could prove really helpful, so that I don't need to spend days figuring out, how things need to be done in the API. How to contact me You can contact me through my GitHub account: https://github.com/kelemen

ever wondering what could be a keyboard shortcut for something in eclipse? in my post on 10 best eclipse shortcuts the question came up how to traverse through all the open files in the editor. finding a shortcut is easy if you know the the mother of all eclipse shortcuts . i press ctrl+3 and enter a search term like ‘switch’, and it shows me all shortcuts with ‘switch’ in the description: ctrl plus 3 shows all shortcuts so with this i know that ctrl+tab is to switch to the next editor. let’s try it out: ctrl+tab popup window a small pop-up window shows all open sources of the editor view: pressing ctrl+tab repeatedly will iterate through the source files. that way i can quickly switch to another source file without leaving my fingers from the keyboard. happy switching

It has been a while since I wanted to have CDI running with JavaFX2. Some people already blogged on how to proceed by getting Guice injection [1] to work with JavaFX & FXML. Well, now it's my turn to provide a way to empower JavaFX with CDI, using Weld as the implementation. My goal was just to have CDI working, no matter how I was using JavaFX, by directly coding in plain Java or using FXML. Ready? Let's go!!! Bootstrap JavaFX & Weld/CDI The launcher class will be the only place where we will have Weld-specific code—all the rest will be totally CDI compliant. The only trick here is to make the application parameters available as a CDI-compliant object so we can reuse them afterwards. Notice also that we use the CDI event mechanism to start up our real application code. public class WeldJavaFXLauncher extends Application { /** * Nothing special, we just use the JavaFX Application methods to boostrap * JavaFX */ public static void main(String[] args) { Application.launch(WeldJavaFXLauncher.class, args); } @SuppressWarnings("serial") @Override public void start(final Stage primaryStage) throws Exception { // Let's initialize CDI/Weld. WeldContainer weldContainer = new Weld().initialize(); // Make the application parameters injectable with a standard CDI // annotation weldContainer.instance().select(ApplicationParametersProvider.class).get().setParameters(getParameters()); // Now that JavaFX thread is ready // let's inform whoever cares using standard CDI notification mechanism: // CDI events weldContainer.event().select(Stage.class, new AnnotationLiteral() {}).fire(primaryStage); } } Start our real JavaFX application Here we start our real application code. We're just listening to the previously fired event (containing the Scene object to render into) so we can start showing our application. In the following example, we load an FXML GUI, but it might have been any node created in any way. public class LoginApplicationStarter { // Let's have a FXMLLoader injected automatically @Inject FXMLLoader fxmlLoader; // Our CDI entry point, we just listen to an event providing the startup scene public void launchJavaFXApplication(@Observes @StartupScene Stage s) { InputStream is = null; try { is = getClass().getResourceAsStream("login.fxml"); // we just load our FXML form (including controler and so on) Parent root = (Parent) fxmlLoader.load(is); s.setScene(new Scene(root, 300, 275)); s.show(); // let's show the scene } catch (IOException e) { throw new IllegalStateException("cannot load FXML login screen", e); } finally { // omitted is cleanup } } } But what about the FXML controller? First let's have a look at the controller we want to use inside our application. It is a pure POJO class annotated with both JavaFX & CDI annotations. // Simple application controller that uses injected fields // to delegate login process and to get default values from the command line using: --user=SomeUser public class LoginController implements Initializable { // Standard FXML injected fields @FXML TextField loginField; @FXML PasswordField passwordField; @FXML Text feedback; // CDI Injected service @Inject LoginService loginService; // Default application parameters retrieved using CDI @Inject Parameters applicationParameters; @FXML protected void handleSubmitButtonAction(ActionEvent event) { feedback.setText(loginService.login(loginField.getText(), passwordField.getText())); } @Override public void initialize(URL location, ResourceBundle resources) { loginField.setText(applicationParameters.getNamed().get("user")); } } In order to have injection working inside the FXML controller, we need to set up JavaFX so that controller objects are created by CDI. As we are in a CDI environment we can also have the FXMLLoader classes injected (that's exactly what we did in the previous LoginApplicationStarter class). How can we achieve this? We just have to provide a Producer class whose responsibility will be to create FXMLLoader instances that are able to load FXML GUIs and instantiate controllers using CDI. The only part that's a little tricky there is that the controller instantiation depends on the required class or interface (using fx:controller in your fxml file). In order to have such a runtime injection/resolution available we use a CDI Instance Object. public class FXMLLoaderProducer { @Inject Instance, Object>() { @Override public Object call(Class param) { return instance.select(param).get(); } }); return loader; } } I hope you found the article interesting and you do not hesitate to comment if you see some errors or possible enhancements. Finally, if you are interested you can find the full source code here. [1] http://andrewtill.blogspot.be/2012/07/creating-javafx-controllers-using-guice.htm

In my office laptop, I have installed two versions of JDK. For the office work, I need JDK6 because the internal framework needs it. I’m using JDK7 for my personal projects and exploring the latest and greatest in Java. I have two versions of Eclipse too (one for office work and one is the latest Juno). But, the tricky thing is to manage these multiple JDKs and IDEs. It’s a piece of cake if I just use Eclipse for compiling my code, because the IDE allows me to configure multiple versions of Java runtime. Unfortunately (or fortunately), I have to use the command line/shell to build my code. So, it is important that I have the right version of JDK present in the PATH and other related environment variables (such as JAVA_HOME). Manually modifying the environment variables every time I want to switch between JDKs, isn’t a happy task. But, thanks to Windows Powershell, I’m able to write a scriplet that can do the heavy-lifting for me. Basically, what I want to achieve is to set PATH variable to add Java bin folder and set the JAVA_HOME environment variable and then launch the correct Eclipse IDE. And, I want to do this with a single command. Let’s do it. Open a Windows Powershell. I prefer writing custom Windows scripts in my profile file so that it is available to run when ever I open the shell. To edit the profile, run this command: notepad.exe $profile - the $profile is a special variable that points to your profile file. Write the below script in the profile file and save it. function myIDE{ $env:Path += "C:\vraa\java\jdk7\bin;" $env:JAVA_HOME = "C:\vraa\java\jdk7" C:\vraa\ide\eclipse\eclipse set-location C:\vraa\workspace\myproject play } function officeIDE{ $env:Path += "C:\vraa\java\jdk6\bin;" $env:JAVA_HOME = "C:\vraa\java\jdk6" C:\office\eclipse\eclipse } Close and restart the Powershell. Now you can issue the command myIDE which will set the proper PATH and environment variables and then launch the eclipse IDE. As you can see, there are two functions with different configurations. Just call the function name that you want to launch from the Powershell command line (myIDE or officeIDE).

Spring core comes out-of-the-box with two scopes: singletons and prototypes. Singletons implement the Singleton pattern, meaning there's only a single instance at runtime (in a JVM). Spring instantiates them during context creation, caches them in the context, and serves them from the cache when needed (or something like that). Prototypes are instantiated each time you access the context to get the bean. Problems arise when you need to inject a prototype-scoped bean in a singleton-scoped bean. Since singletons are created (and then injected) during context creation: it's the only time the Spring context is accessed and thus prototype-scoped beans are injected only once, thus defeating their purpose. In order to inejct prototypes into singletons, and side-by-syde with setter and constructor injection, Spring proposes another way for injection, called method injection. It works in the following way: since singletons are instantiated at context creation, it changes the way prototype-scoped are handled, from injection to created by an abstract method. The following snippet show the unsuccessful way to achieve injection: public class Singleton { private Prototype prototype; public Singleton(Prototype prototype) { this.prototype = prototype; } public void doSomething() { prototype.foo(); } public void doSomethingElse() { prototype.bar(); } } The next snippet displays the correct code: public abstract class Singleton { protected abstract Prototype createPrototype(); public void doSomething() { createPrototype().foo(); } public void doSomethingElse() { createPrototype().bar(); } } As you noticed, code doesn't specify the createPrototype() implementation. This responsibility is delegated to Spring, hence the following needed configuration: Note that an alternative to method injection would be to explicitly access the Spring context to get the bean yourself. It's a bad thing to do since it completely defeats the whole Inversion of Control pattern, but it works (and is essentially the only option when a nasty bug happens on the server - see below).However, using method injection has several main limitations: Spring achieves this black magic by changing bytecode. Thus, you'll need to have the CGLIB libraryon the classpath. The feature is only available by XML configuration, no annotations (see this JIRAfor more information) Finally, some application servers have bugs related to CGLIB (such as this one) To go further: Spring's documentation on method injection

Here is a quick example of how to programmatically access Camel MBeans to monitor and manipulate routes... first, get a connection to a JMX server (assumes localhost, port 1099, no auth) note, always cache the connection for subsequent requests (can cause memory utilization issues otherwise) JMXServiceURL url = new JMXServiceURL("service:jmx:rmi:///jndi/rmi://localhost:1099/jmxrmi"); JMXConnector jmxc = JMXConnectorFactory.connect(url); MBeanServerConnection server = jmxc.getMBeanServerConnection(); use the following to iterate over all routes and retrieve statistics (state, exchanges, etc)... ObjectName objName = new ObjectName("org.apache.camel:type=routes,*"); List cacheList = new LinkedList(server.queryNames(objName, null)); for (Iterator iter = cacheList.iterator(); iter.hasNext();) { objName = iter.next(); String keyProps = objName.getCanonicalKeyPropertyListString(); ObjectName objectInfoName = new ObjectName("org.apache.camel:" + keyProps); String routeId = (String) server.getAttribute(objectInfoName, "RouteId"); String description = (String) server.getAttribute(objectInfoName, "Description"); String state = (String) server.getAttribute(objectInfoName, "State"); ... } use the following to execute operations against a Camel route (stop,start, etc) ObjectName objName = new ObjectName("org.apache.camel:type=routes,*"); List cacheList = new LinkedList(server.queryNames(objName, null)); for (Iterator iter = cacheList.iterator(); iter.hasNext();) { objName = iter.next(); String keyProps = objName.getCanonicalKeyPropertyListString(); if(keyProps.contains(routeID)) { ObjectName objectRouteName = new ObjectName("org.apache.camel:" + keyProps); Object[] params = {}; String[] sig = {}; server.invoke(objectRouteName, operationName, params, sig); return; } } summary These APIs can easily be used to build a web or command line based tool to support remote Camel management features. All of these features are available via the JMX console and Camel does provide a web console to support some management/monitoring tasks. See these pages for more information... http://camel.apache.org/camel-jmx.html http://camel.apache.org/web-console.html

the great thing with blogging is: i receive great comments, questions and ideas. the great thing with eclipse/codewarrior is that the extensions are almost unlimited . for my earlier post on hiding the toolbar i received a tip for another way which even is better: a plugin to switch eclipse into full screen mode. here is how to install it and how it looks… the plugin is available from http://code.google.com/p/eclipse-fullscreen/ . download the zip file. the zip file has the cn.pande.eclipsex.fullscreen_.jar file. copy that file inside the codewarrrior or eclipse eclipse\plugins folder. after launching eclipse there is new entry in the window menu: full screen menu item this switches eclipse into full screen mode: eclipse in full screen mode this hides the toolbar, menu and status bar, and i have more space available for what matters how to get out of full screen mode: press esc key to exit full screen mode. ctrl+alt+z is the default shortcut to toggle between ‘normal’ and ‘full screen’ mode. happy full screening

we wanted to set up a nightly integration build with our projects so that we could run unit and integration tests on the latest version of our applications and their underlying libraries. we have a number of libraries that are shared across multiple projects and we wanted this build to run every night and use the latest versions of those libraries even if our applications had a specific release version defined in their maven pom file. in this way we would be alerted early if someone added a change to one of the dependency libraries that could potentially break an application when the developer upgraded the dependent library in a future version of the application. the chart below illustrates our dependencies between our libraries and our applications. updating versions nightly both the crossdock-shared and messaging-shared libraries depend on the siesta framework library. the crossdock web service and crossdockmessaging applications both depend on the crossdock-shared and messaging-shared libraries. because of the dependency structure, we wanted the siestaframework library built first. the crossdock-shared and messaging-shared libraries could be built in parallel, but we didn’t want the builds for the crossdock web service and crossdockmessaging applications to begin until all the libraries had finished building. we also wanted the nightly build to tag a subversion with the build date as well as upload the artifact to our nexus “nightly build” repository. the resulting artifact would look something like siestaframework-20120720.jar also as i had mentioned, even though the crossdockmessaging app may specify in its pom file it depends on version 5.0.4 of the siestaframework library. for the purposes of the nightly build, we wanted it to use the freshly built siestaframework-nightly-20120720.jar version of the library. the first problem to tackle was getting the current date into the project’s version number. for this i started with the jenkins zentimestamp plugin . with this plugin the format of jenkin’s build_id timestamp can be changed. i used this to specify using the format of yyyymmdd for the timestamp. the next step was to get the timestamp into the version number of the project. i was able to accomplish this by using the maven versions plugin. one thing the versions plugin can do is allow you to dynamically override the version number in the pom file at build time. the code snippet from the siestaframework’s pom file is below. org.codehaus.mojo versions-maven-plugin 1.3.1 at this point the jenkins job can be configured to invoke the “versions;set” goal, passing in the new version string to use. the ${build_id} jenkins variable will have the newly formatted date string. this will produce an artifact with the name siestaframework-nightly-20120720.jar uploading artifacts to a nightly repository since this job needed to upload the artifact to a different repository from our release repository that's defined in our project pom files, the “altdeploymentrepository” property was used to pass in the location of the nightly repository. the deployment portion of the siestaframework job specifies the location of the nightly repository where ${lynden_nightly_repo} is a jenkins variable containing the nightly repo url. tagging subversion finally, the jenkins subversion tagging plugin was used to tag svn if the project was successfully built. the plugin provides a post-build action for the job with the configuration section shown below. dynamically updating dependencies so now that the main project is set up, the dependent projects are set up in a similar way, but need to be configured to use the siestaframework-nightly-20120720 of the dependency rather than whatever version they currently have specified in their pom file. this can be accomplished by changing the pom to use a property for the version number of the dependency. for example, if the snippet below was the original pom file— com.lynden siestaframework 5.0.1 —changing it to the following would allow the siestaframework version to be set dynamically: 5.0.1 com.lynden siestaframework ${siesta.version} this version can then be overriden by the jenkins job. the example below shows the jenkins configuration for the crossdock-shared build. enforcing build order the final step in this process is setting up a structure to enforce the build order of the projects. the dependencies are set up in such a way that siestaframework needs to be built first, and the crossdock-shared and messaging-shared libraries can be run concurrently once siestaframework finishes. the crossdock web service and crossdockmessaging application jobs can be run concurrently, too, but not until after both shared libraries have finished. setting up the crossdock-shared and messaging-shared jobs to be built after the siestaframework finishes is pretty straightforward. in the jenkins job configuration for both the shared libraries, the following build trigger is added: to satisfy the requirement that the apps build only after all libraries have built, i enlisted the help of the join plugin . the join plugin can be used to execute a job once all “downstream” jobs have completed. what does this mean exactly? looking at the diagram below, the crossdock-shared and the messaging-shared jobs are “downstream” from the siestaframework job. once both of these jobs complete, a join trigger can be used to start other jobs. in this case, rather than having the join trigger kick off other app jobs directly, i created a dummy join job. in this way, as we add more application builds, we don’t need to keep modifying the siestaframework job with the new application job we just added. to illustrate the configuration, siestaframework has a new post-build action (below): join-build is a jenkins job i configured that does not do anything when executed. then our crossdock web service and crossdockmessaging applications define their builds to trigger as soon as join-build has completed. in this way we are able to run builds each night that will update to the latest version of our dependencies as well as tag svn and archive the binaries to nexus. i’d love to hear feedback from anyone who is handling nightly builds via jenkins, and how they have handled the configuration and build issues.

Autoscaling your webserver tier is typically straightforward. Image your apache server with source code or without, then sync down files from S3 upon spinup. Roll that image into the autoscale configuration and you’re all set. With the database tier though, things can be a bit tricky. The typical configuration we see is to have a single master database where your application writes. But scaling out or horizontally on Amazon EC2 should be as easy as adding more slaves, right? Why not automate that process? Below we’ve set out to answer some of the questions you’re likely to face when setting up slaves against your master. We’ve included instructions on building an AMI that automatically spins up as a slave. Fancy! How can I autoscale my database tier? Build an auto-starting MySQL slave against your master. Configure those to spinup. Amazon’s autoscaling loadbalancer is one option, another is to use a roll-your-own solution, monitoring thresholds on servers, and spinning up or dropping off slaves as necessary. Does an AWS snapshot capture subvolume data or just the SIZE of the attached volume? In fact, if you have an attached EBS volume and you create an new AMI off of that, you will capture the entire root volume, plus your attached volume data. In fact we find this a great way to create an auto-building slave in the cloud. How do I freeze MySQL during AWS snapshot? mysql> flush tables with read lock;mysql> system xfs_freeze -f /data At this point you can use the Amazon web console, ylastic, or ec2-create-image API call to do so from the command line. When the server you are imaging off of above restarts – as it will do by default – it will start with /data partition unfrozen and mysql’s tables unlocked again. Voila! If you’re not using xfs for your /data filesystem, you should be. It’s fast! The xfsprogs docs seem to indicate this may also work with foreign filesystems. Check the docs for details. How do I build an AMI mysql slave that autoconnects to master? Install mysql_serverid script below. Configure mysql to use your /data EBS mount. Set all your my.cnf settings including server_id Configure the instance as a slave in the normal way. When using GRANT to create the ‘rep’ user on master, specify the host with a subnet wildcard. For example ’10.20.%’. That will subsequently allow any 10.20.x.y servers to connect and replicate. Point the slave at the master. When all is running properly, edit the my.cnf file and remove server_id. Don’t restart mysql. Freeze the filesystem as described above. Use the Amazon console, ylastic or API call to create your new image. Test it of course, to make sure it spins up, sets server_id and connects to master. Make a change in the test schema, and verify that it propagates to all slaves. How do I set server_id uniquely? As you hopefully already know, in MySQL replication environment each node requires a unique server_id setting. In my Amazon Machine Images, I want the server to startup and if it doesn’t find the server_id in the /etc/my.cnf file, to add it there, correctly! Is that so much to ask? Here’s what I did. Fire up your editor of choice and drop in this bit of code: #!/bin/shif grep -q “server_id” /etc/my.cnf then : # do nothing – it’s already set else # extract numeric component from hostname – should be internet IP in Amazon environment export server_id=`echo $HOSTNAME | sed ‘s/[^0-9]*//g’` echo “server_id=$server_id” >> /etc/my.cnf # restart mysql /etc/init.d/mysql restart fi Save that snippet at /root/mysql_serverid. Also be sure to make it executable: $ chmod +x /root/mysql_serverid Then just append it to your /etc/rc.local file with an editor or echo: $ echo "/root/mysql_serverid" >> /etc/rc.local Assuming your my.cnf file does *NOT* contain the server_id setting when you re-image, then it’ll set this automagically each time you spinup a new server off of that AMI. Nice! Can you easily slave off of a slave? How? It’s not terribly different from slaving off of a normal master. A. First enable slave updates. The setting is not dynamic, so if you don’t already have it set, you’ll have to restart your slave. log_slave_updates=true B. Get an initial snapshot of your slave data. You can do that the locking way: mysql> flush tables with read lock;mysql> show master status\G; mysql> system mysqldump -A > full_slave_dump.mysql mysql> unlock tables; You may also choose to use Percona’s excellent xtrabackup utility to create hotbackups without locking any tables. We are very lucky to have an open-source tool like this at our disposal. MySQL Enterprise Backup from Oracle Corp can also do this. C. On the slave, seed the database with your dump created above. $ mysql < full_slave_dump.mysql D. Now point your slave to the original slave. mysql> change master to master_user='rep', master_password='rep', master_host='192.168.0.1', master_log_file='server-bin-log.000004', master_log_pos=399;mysql> start slave; mysql> show slave status\G; Slave master is set as an IP address. Is there another way? It’s possible to use hostnames in MySQL replication, however it’s not recommended. Why? Because of the wacky world of DNS. Suffice it to say MySQL has to do a lot of work to resolve those names into IP addresses. A hickup in DNS can interrupt all MySQL services potentially as sessions will fail to authenticate. To avoid this problem do two things: A. Set this parameter in my.cnf skip_name_resolve = true Remove entries in mysql.user table where hostname is not an IP address. Those entries will be invalid for authentication after setting the above parameter. Doesn’t RDS take care of all of this for me? RDS is Amazon’s Relational Database Service which is built on MySQL. Amazon’s RDS solution presents MySQL as a service which brings certain benefits to administrators and startups: Simpler administration. Nuts and bolts are handled for you. Push-button replication. No more struggling with the nuances and issues of MySQL’s replication management. Simplicity of administration of course has it’s downsides. Depending on your environment, these may or may not be dealbreakers. No access to the slow query log. This is huge. The single best tool for troubleshooting slow database response is this log file. Queries are a large part of keeping a relational database server healthy and happy, and without this facility, you are severely limited. Locked in downtime window When you signup for RDS, you must define a thirty minute maintenance window. This is a weekly window during which your instance *COULD* be unavailable. When you host yourself, you may not require as much downtime at all, especially if you’re using master-master mysql and zero-downtime configuration. Can’t use Percona Server to host your MySQL data. You won’t be able to do this in RDS. Percona server is a high performance distribution of MySQL which typically rolls in serious performance tweaks and updates before they make it to community addition. Well worth the effort to consider it. No access to filesystem, server metrics & command line. Again for troubleshooting problems, these are crucial. Gathering data about what’s really happening on the server is how you begin to diagnose and troubleshoot a server stall or pileup. You are beholden to Amazon’s support services if things go awry. That’s because you won’t have access to the raw iron to diagnose and troubleshoot things yourself. Want to call in an outside consultant to help you debug or troubleshoot? You’ll have your hands tied without access to the underlying server. You can’t replicate to a non-RDS database. Have your own datacenter connected to Amazon via VPC? Want to replication to a cloud server? RDS won’t fit the bill. You’ll have to roll your own – as we’ve described above. And if you want to replicate to an alternate cloud provider, again RDS won’t work for you. Related posts: Deploying MySQL on Amazon EC2 – 8 Best Practices Review: Host Your Web Site In The Cloud, Amazon Web Services Made Easy 5 Ways to Boost MySQL Scalability Top MySQL DBA interview questions (Part 2) MySQL Cluster In The Cloud – Managers Guide

Changing your perspective even a small amount can have profound effects on how you approach your system. Let’s say you’re writing a web application in Java. In the system you deal with orders, customers and products. As a web application, your classes include staples like PersonController, PersonRepository, CustomerController and OrderService. How do you organize your classes into packages? There are two fundamental ways to structure your packages. Either you can focus on the logical tiers, like com.brodwall.myapp.controllers, com.brodwall.myapp.domain or perhaps com.brodwall.myapp.services.customer. Or you can focus on the domain contexts, like com.brodwall.myapp.customer, com.brodwall.myapp.orders and com.brodwall.myapp.products. The first approach is by far the most prevalent. In my view, it’s also the least helpful. Here are some ways your thinking changes if you structure your packages around domain concepts, rather than technological tiers: First, and most fundamentally, your mental model will now be aligned with that of the users of your system. If you’re asked to implement a typical feature, it is now more likely to be focused around a strict subset of the packages of your system. For example, adding a new field to a form will at least affect the presentation logic, entity and persistence layer for the corresponding domain concept. If your packages are organized around tiers, this change will hit all over your system. In a word: A system organized around features, rather than technologies, have higher coherence. This technical term means that a large percentage of a the dependencies of a class are located close to that class. Secondly, organizing around domain concepts will give you more options when your software grows. When a package contains tens of classes, you may want to split it up in several packages. The discussion can itself be enlightening. “Maybe we should separate out the customer address classes into a com.brodwall.myapp.customer.address package. It seems to have a bit of a life on its own.” “Yeah, and maybe we can use the same classes for other places we need addresses, such as suppliers?” “Cool, so com.brodwall.myapp.address, then?” Or maybe you decide that order status codes and payment status codes deserve to be in the “com.brodwall.myapp.order.codes” package. On the other hand, what options do you have for splitting up com.brodwall.myapp.controllers? You could create subpackages for customer, orders and products, but these subpackages may only have one or possibly two classes each. Finally, and perhaps most intriguingly, using domain concepts for packages allows you to vary the design according on a case by case basis. Maybe you really need a OrderService which coordinates the payment and shipping of an order, while ProductController only needs basic create-retrieve-update-delete functionality with a repository. A ProductService would just get in the way. If ProductService is missing from the com.brodwall.myapp.services package, this may be confusing or at the very least give you a nagging feeling that something is wrong. On the other hand, if there’s no Controller in the com.brodwall.myapp.product package, it doesn’t matter much. Also, most systems have some good parts and some not-so-good parts. If your Services package is not working for you, there’s not much you can do. But if the Products package is rotten, you can throw it out and reimplement it without the whole system being thrown into a state of chaos. By putting the classes needed to implement a feature together with each other and apart from the classes needed to implement other features, developers can be pragmatic and innovative when developing one feature without negatively affecting other features. The flip side of this is that most developers are more comfortable with some technologies in the application and less comfortable with other technologies. Organizing around features instead of technologies force each developer to consider a larger set of technological challenges. Some programmers take this as a motivating challenge to learn, while others, it seems, would rather not have to learn something new. If it were my money being spend to create features, I know what kind of developer I would want. Trivial changes can have large effects. By organizing your software around features, you get a more coherent system that allows for growth. It may challenge your developers, but it drives down the number of hand-offs needed to implement a feature and it challenges the developers to improve the parts of the application they are working on. See also my blog post on Architecture as tidying up.