Saturday, April 12, 2014

Spring Boot on OpenShift

I have a Spring Boot application that I would like to deploy to OpenShift. Unfortunately the Spring Boot documentation is silent about OpenShift, although it does contain information about other cloud providers (of course Pivotal's Clound Foundry but also Heroku).

This is a how-to on how I deployed my Spring Boot application to OpenShift as a prebuilt WAR file. This entry is pieced together from various resources from the OpenShift and Spring Boot documentation.

Spring Boot Configuration


General:

In the application you need to have a class like the following (note the extends part and the configure method that you don't normally have in Spring Boot - the main method would suffice):

@Configuration
@EnableAutoConfiguration
@EnableMongoRepositories
@ComponentScan
public class Booter extends SpringBootServletInitializer {

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(Booter.class);
    }


    public static void main(String[] args) throws Exception {
        SpringApplication.run(Booter.class, args);
    }

}

You also need to add this to your pom.xml:
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-tomcat</artifactId>
    <scope>provided</scope>
</dependency>

For local development I use the console to fire up the application with the maven command:
mvn spring-boot:run

Read more about the pom.xml changes and the SpringBootServletInitializer here and here.

Actuator:

I use the actuator plugin in Spring Boot. However, on OpenShift you must rename the /health endpoint (read on to know why). The easiest way to do this is simply to change all actuator endpoints using an application property with a line like this (make an application.properties file and put it in the src/main/resources folder in the application):

management.context-path=/manage

That will map for instance /health to /manage/health instead.

Mongo:

To use Mongo you need to use the url, port, user and password given by OpenShift. I use the following bean definition to shift between OpenShift and my test system.

@Bean
public MongoTemplate mongoTemplate() throws Exception {

    if (System.getenv("OPENSHIFT_MONGODB_DB_HOST") != null) {

        LOG.info("Connecting to OpenShift Mongo");

        String openshiftMongoDbHost = System.getenv("OPENSHIFT_MONGODB_DB_HOST");
        int openshiftMongoDbPort = Integer.parseInt(System.getenv("OPENSHIFT_MONGODB_DB_PORT"));
        String username = System.getenv("OPENSHIFT_MONGODB_DB_USERNAME");
        String password = System.getenv("OPENSHIFT_MONGODB_DB_PASSWORD");
        Mongo mongo = new MongoClient(openshiftMongoDbHost, openshiftMongoDbPort);
        UserCredentials userCredentials = new UserCredentials(username, password);
        String databaseName = System.getenv("OPENSHIFT_APP_NAME");
        MongoDbFactory mongoDbFactory = new SimpleMongoDbFactory(mongo, databaseName, userCredentials);
        MongoTemplate mongoTemplate = new MongoTemplate(mongoDbFactory);
        return mongoTemplate;
        
    } else {

        LOG.info("Connecting to test Mongo");

        return new MongoTemplate(new SimpleMongoDbFactory(new MongoClient(), "test"));
    }
}


OpenShift


Application type:

I use the Tomcat 7 (JBoss EWS 2.0) cartridge with scaling plus the MongoDB cartridge. I started by checking out the code using git clone, removed the src folder and the pom.xml file (as I am deploying WAR style).

The actual deployment is pretty simple. After building with mvn package I copy the generated WAR file to the webapps folder, rename it to ROOT.war as I want it to be mapped to my-app.rhcloud.com (and not my-app.rhcloud.com/some-other-thing). Then I git add, commit and push. That is also described here.

HAProxy (scaling):

If you use scaling in you application you need to know about HAProxy which monitors you application by calling the / path unless you do something. HAProxy expects a 200 OK HTTP answer back. My app returns 404 when accessing /, hence HAProxy thinks the application is down. 503 is returned for everything except for calls to /health, but more on that later.

To fix it, ssh into your app and go to the haproxy folder. Then edit the file conf/haproxy.conf, specifically you need to modify the line shown below (almost at the bottom of the file) to whatever path you want HAProxy to monitor:

option httpchk GET /

You should probably choose the path carefully and not a path that requires a lot of server power to process as HAProxy polls the path rather often to check the application state. Afterwards do this in the console:

bin/control restart

to make the change have effect. HAProxy is described here.

/health:

/health has a special meaning on OpenShift, luckily you have already mapped the /health from Spring Boot actuator to /manage/health.

The OpenShift /health mapping is described here.


That's all folks.

Friday, April 11, 2014

NetBeans NetCAT 8.0


I think that some people thought I was harsh in my entry on NetBeans vs. IntellJ IDEA. As I wrote I actually did a lot work in getting to know the IDEs, especially NetBeans where I joined the NetCAT.

Yesterday I got a mail from NetBeans notifying me that some of the bugs I filed were indeed solved in the 8.0 final release. I especially like that 241120 was fixed as it was quite annoying in refactoring. Good job.

Dear NetBeans User,
In the past you have taken the time to report issues that you encountered while using NetBeans software. A new version (NetBeans 8.0) has just been released,and we'd like to inform you that the following issue(s) you reported have been addressed in the new release:
239915Unpacking index is extremely slow
240039Double "Unit tests" folders in New file dialog
240189[regression] broken "Go To Source" in Find Usages tab
240639NullPointerException at org.netbeans.modules.web.jsf.editor.actions.NamespaceProcessor.computeImportData
240696NullPointerException at org.netbeans.modules.web.debug.EngineContextProviderImpl.getDefaultContext
240699XML gets formatted as HTML in Variables view
241120Too many return values.
241723java.io.FileNotFoundException: http://docs.angularjs.org/api/guide/ie
Please visit the netbeans.org website to download NetBeans 8.0 and to learn more about the new release.
We appreciate your contribution to our efforts to make NetBeans software and features better for all users. And as always, we look forward to your feedback on how we can continue to improve NetBeans.Thank you.
The NetBeans Team

Looking for a Java Profiler. No IntelliJ IDEA profiler? What to do?

I have previously written about NetBeans 8 vs. IntelliJ IDEA 13. One thing I am missing in IntelliJ is a profiler. The advantages in having a profiler integrated into the IDE compared to having the profiler running on the side are multiple: the profiler is integrated into the IDE's start application functionality and so is the ability to go directly to the (slow) profiled code to name a few.

However, IDEA does not ship with a profiler. I know that it integrates very nicely with JProfiler but that is a rather expensive tool. This led me to look for other options. I have previously used VisualVM but Mission Control caught my eye as it has a cool feature called Flight Recorder (a low overhead profiler that you can use in production). It requires you have a recent JVM that bundles Mission Control (a recent Java 7 or 8 will do) + for running your app with the extra options that I'll show below.

Run options


From within IDEA: 

To address the first problem, profiling a unit test or app from with IDEA, here is what I do. When you start you app or unit test from with in IDEA add this to the run configuration's VM options:

-XX:+UnlockCommercialFeatures -XX:+FlightRecorder -XX:StartFlightRecording=duration=120m,filename=recording.jfr

It starts the flight recorder immediately and runs it for up to 120 minutes. It puts the results in a file called recording.jfr in the root project folder. When done or after 120 minutes you can then open the file using Mission Control and view for instance the Code tab's Hot Methods tab.

Of course you can also just connect Mission Control to the running process that is execution you code directly. You do this by having Mission Control open and select the the Flight Recorder item in the JVM Browser of the process. But it is nice to know that you can make it start along side the actual application start using the above configuration.

Options intermezzo:

When you want to do more experimentation you can add an extra settings argument to the XX:StartFlightRecording (see Maven example below). The argument must equal a file name in the JRE_HOME/lib/jfr folder. The files contain information on for instance sampling rate, what will be recorded (for instance what JVM and OS metrics) etc. You can edit it in Mission Control in the Flight Recording Template Manager.

From the console using Maven:

If you prefer the console, here are some nifty Maven commands:

To run tests that match Profile* and profile them (note that if you use Surefire and already have an argLine in the pom.xml file, then you can't override it from the console):

mvn -Dtest=Profile* test -DargLine="-XX:+UnlockCommercialFeatures -XX:+FlightRecorder -XX:StartFlightRecording=filename=result.jfr,duration=120m,settings=MyWicketSettings.jfc"

Run app with profiling enabled (here a Spring boot app):

MAVEN_OPTS="-XX:+UnlockCommercialFeatures -XX:+FlightRecorder" mvn spring-boot:run

With that command you have enabled Flight Recorder. You can then open Mission Control when you want to look at the apps performance etc.