DDevelopment & Design

JMS redelivery with ActiveMQ and Servicemix

The other day I felt a compelling need to implement a JMS redelivery scenario. The exact scenario I’d been trying to handle was:

  1. my message is in an ActiveMQ queue or topic
  2. its processing fails, because of some exception – ie. database access exception due to server nonavailability
  3. since we get an exception, the message is not handled properly, we may want to retry processing attempt some time later
  4. of course, for the redelivery to happen we need the message to stay in the ActiveMQ queue – fetching messages from the queue will be stopped until the redelivery succeeds or expires

See how this can be done after the jump :)

For this to happen, I’ve tried implementing Apache Camel route, but as it turns out, Camel fails to deliver facilities for exact JMS redelivery. It is possible to set JMS connection in transacted mode, but the redeliveries happen one after another and fixed times.

What I’ve ended up doing was implement a servicemix-jms endpoint. I’ve used this configuration for it:


            activemq/connectionFactory

            activemq/resourceAdapter

As you can see, we lookup a couple of things in JNDI registry, so you need to have them configured on the Servicemix side – a sample config presented farther in this entry.

The bean responsible for configuring redelivery settings is activationSpec. You can set various things with it, like:

  • initial redelivery delay
  • maximum number of redeliveries
  • backoff multiplier
  • …

What is really important in jms:endpoint config for this to work are:

  • processorName=”jca”
  • rollbackOnError=”true”

Servicemix should have the following entries in its jndi registry:

          

(...) 

       xmlns:jencks="http://jencks.org/2.0"
       xmlns:amqra="http://activemq.apache.org/schema/ra" -->

When the redeliveries are exhausted, message is routed to global Dead Letter Queue called ActiveMQ.DLQ. Since this is a single bag for all the failed messages from all queues, you may want to configure this aspect differently. For example you can tell ActiveMQ to create a single DLQ for each queue. Use this config to achieve it – the changes should be made to Broker configuration.


        

            

  ...

More on the subject of redelivieries in ActiveMQ can be found at http://activemq.apache.org/message-redelivery-and-dlq-handling.html.

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DDevelopment & Design

Spock, Java and Maven

Few months ago I've came across Groovy - powerful language for JVM platform which combines the power of Java with abilities typical for scripting languages (dynamic typing, metaprogramming).

Together with Groovy I've discovered spock framework (https://code.google.com/p/spock/) - specification framework for Groovy (of course you can test Java classes too!). But spock is not only test/specification framework - it also contains powerful mocking tools.

Even though spock is dedicated for Groovy there is no problem with using it for Java classes tests. In this post I'm going to describe how to configure Maven project to build and run spock specifications together with traditional JUnit tests.


Firstly, we need to prepare pom.xml and add necessary dependencies and plugins.

Two obligatory libraries are:
<dependency>
    <groupid>org.spockframework</groupId>
    <artifactid>spock-core</artifactId>
    <version>0.7-groovy-2.0</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupid>org.codehaus.groovy</groupId>
    <artifactid>groovy-all</artifactId>
    <version>${groovy.version}</version>
    <scope>test</scope>
</dependency>
Where groovy.version is property defined in pom.xml for more convenient use and easy version change, just like this: 
<properties>
    <gmaven-plugin.version>1.4</gmaven-plugin.version>
    <groovy.version>2.1.5</groovy.version>
</properties>

I've added property for gmaven-plugin version for the same reason ;)

Besides these two dependencies, we can use few additional ones providing extra functionality:
  • cglib - for class mocking
  • objenesis - enables mocking classes without default constructor
To add them to the project put these lines in <dependencies> section of pom.xml:
<dependency>
    <groupid>cglib</groupId>
    <artifactid>cglib-nodep</artifactId>
    <version>3.0</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupid>org.objenesis</groupId>
    <artifactid>objenesis</artifactId>
    <version>1.3</version>
    <scope>test</scope>
</dependency>

And that's all for dependencies section. Now we will focus on plugins necessary to compile Groovy classes. We need to add gmaven-plugin with gmaven-runtime-2.0 dependency in plugins section:
<plugin>
    <groupid>org.codehaus.gmaven</groupId>
    <artifactid>gmaven-plugin</artifactId>
    <version>${gmaven-plugin.version}</version>
    <configuration>
        <providerselection>2.0</providerSelection>
    </configuration>
    <executions>
        <execution>
            <goals>
                <goal>compile</goal>
                <goal>testCompile</goal>
            </goals>
        </execution>
    </executions>
    <dependencies>
        <dependency>
            <groupid>org.codehaus.gmaven.runtime</groupId>
            <artifactid>gmaven-runtime-2.0</artifactId>
            <version>${gmaven-plugin.version}</version>
            <exclusions>
                <exclusion>
                    <groupid>org.codehaus.groovy</groupId>
                    <artifactid>groovy-all</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupid>org.codehaus.groovy</groupId>
            <artifactid>groovy-all</artifactId>
            <version>${groovy.version}</version>
        </dependency>
    </dependencies>
</plugin>

With these configuration we can use spock and write our first specifications. But there is one issue: default settings for maven-surefire plugin demand that test classes must end with "..Test" postfix, which is ok when we want to use such naming scheme for our spock tests. But if we want to name them like CommentSpec.groovy or whatever with "..Spec" ending (what in my opinion is much more readable) we need to make little change in surefire plugin configuration:
<plugin>
    <groupid>org.apache.maven.plugins</groupId>
    <artifactid>maven-surefire-plugin</artifactId>
    <version>2.15</version>
    <configuration>
        <includes>
            <include>**/*Test.java</include>
            <include>**/*Spec.java</include>
        </includes>
    </configuration>
</plugin>

As you can see there is a little trick ;) We add include directive for standard Java JUnit test ending with "..Test" postfix, but there is also an entry for spock test ending with "..Spec". And there is a trick: we must write "**/*Spec.java", not "**/*Spec.groovy", otherwise Maven will not run spock tests (which is strange and I've spent some time to figure out why Maven can't run my specs).

Little update: instead of "*.java" postfix for both types of tests we can write "*.class" what is in my opinion more readable and clean:
<include>**/*Test.class</include>
<include>**/*Spec.class</include>
(thanks to Tomek Pęksa for pointing this out!)

With such configuration, we can write either traditional JUnit test and put them in src/test/java directory or groovy spock specifications and place them in src/test/groovy. And both will work together just fine :) In one of my next posts I'll write something about using spock and its mocking abilities in practice, so stay in tune.

DDevelopment & Design

Spring security authentication-success-handler-ref and authentication-failure-handler-ref does not work with KerberosServiceAuthenticationProvider

I'm using SpringSecurity with KerberosServiceAuthenticationProvider which is Kerberos security extension. You can read how to use it on extension author's blog.But you cannot use handler on form-login to catch authorization result. It's because of inne...I'm using SpringSecurity with KerberosServiceAuthenticationProvider which is Kerberos security extension. You can read how to use it on extension author's blog.But you cannot use handler on form-login to catch authorization result. It's because of inne...