How to develop his own plugin

This feature is only possible with Hadoop Unit v3.x.

There are 2 classes which have to be implemented:

a class that implements Bootstrap (from module hadoop-unit-commons) or BootstrapHadoop (from module hadoop-unit-commons-hadoop)
a class that implements ComponentMetadata (from module hadoop-unit-commons)

Moreover, as Service Provider Interface is used, the file META-INF/services/fr.jetoile.hadoopunit.component.Bootstrap has to be present with the reference to the class which implements the interface Bootstrap or BootstrapHadoop.

Interface Bootstrap

This interface define 6 methods:

start() which is called when the plugin is started
stop() which is called when the plugin is stopped
getProperties() which is called when the banner is printed
loadConfig(Map<String, String> configs) which is called to get overrided properties by the maven’s plugin
getMetadata() which return the plugin’s metadata as dependencies and so on
getName() which is a default method which lookup into the implementation of ComponentMetadata to get the plugin name

elastic_class

Interface BootstrapHadoop

This interface extends the interface Bootstrap but declare the method getConfiguration() which return an instance of org.apache.hadoop.conf.Configuration.

bootstrap_class

Interface ComponentMetadata

This interface defines 2 methods:

getName() which gives the plugin’s name
getDependencies() which lists the plugins the current plugin is dependent

componentMetadata_class

Add a plugin to Hadoop Unit Standalone

To add a plugin to Hadoop Unit in the standalone mode, add the following information into the file hadoop-unit-default.properties:

<pluginName>.artifactId which must have the format <groupId>:<artifactId>:<version>
<pluginName>.mainClass which must indicate the implementation of Bootstrap or BootstrapHadoop
<pluginName>.metadataClass which must indicate the implementation of ComponentMetadata

Note : the plugin’s jar has to be in your repository manager (or on maven central) as it will be searched and downloaded.

Sample of hadoop-unit-default.properties:

hdfs.artifactId=fr.jetoile.hadoop:hadoop-unit-hdfs:3.1
hdfs.mainClass=fr.jetoile.hadoopunit.component.HdfsBootstrap
hdfs.metadataClass=fr.jetoile.hadoopunit.component.HdfsMetadata

Add your plugin’s name into the file hadoop.properties.

Sample of hadoop.properties:

<pluginName>=true

Note that your plugin name has to be in lowercase and that his name declared into the ComponentMetadata’s class has to be in uppercase.

Add a plugin to Hadoop Unit’s maven plugin

To add a plugin to Hadoop Unit’s maven plugin, add your plugin into the configuration element as shown below:

<build>
    <plugins>
        <plugin>
            <artifactId>hadoop-unit-maven-plugin</artifactId>
            <groupId>fr.jetoile.hadoop</groupId>
            <version>${hadoop-unit.version}</version>
            <executions>
                <execution>
                    <id>start</id>
                    <goals>
                        <goal>embedded-start</goal>
                    </goals>
                    <phase>pre-integration-test</phase>
                </execution>
                <execution>
                    <id>embedded-stop</id>
                    <goals>
                        <goal>embedded-stop</goal>
                    </goals>
                    <phase>post-integration-test</phase>
                </execution>
            </executions>
            <configuration>
                <components>
                    <componentArtifact implementation="fr.jetoile.hadoopunit.ComponentArtifact">
                        <componentName>HDFS</componentName>
                        <artifactId>hadoop-unit-hdfs</artifactId>
                        <groupId>fr.jetoile.hadoop</groupId>
                        <version>${hadoop-unit.version}</version>
                        <mainClass>fr.jetoile.hadoopunit.component.HdfsBootstrap</mainClass>
                    </componentArtifact>
                </components>
            </configuration>
        </plugin>
    </plugins>
</build>

Note : the plugin’s jar has to be in your repository manager (or on maven central) as it will be searched and downloaded.

HDFS Sample

This diagram shows the hdfs’ plugin class diagram:

hdfs_class

This diagram shows a class diagram with multiple plugins:

multiple_class

hadoop-unit-site