Building components with Maven

To develop new components, Talend Component Kit requires a build tool in which you will import the component project generated from the starter. With this build tool, you will also be able to implement the logic of your component and to install and deploy it to Talend applications. A Talend Component Kit plugin is available for each of the supported build tools.

talend-component-maven-plugin helps you write components that match best practices and generate transparently metadata used by Talend Studio.

You can use it as follows:

<plugin>
  <groupId>org.talend.sdk.component</groupId>
  <artifactId>talend-component-maven-plugin</artifactId>
  <version>${component.version}</version>
</plugin>

This plugin is also an extension so you can declare it in your build/extensions block as:

<extension>
  <groupId>org.talend.sdk.component</groupId>
  <artifactId>talend-component-maven-plugin</artifactId>
  <version>${component.version}</version>
</extension>

Used as an extension, the dependencies, validate and documentation goals will be set up.

Dependencies

The first goal is a shortcut for the maven-dependency-plugin. It creates the TALEND-INF/dependencies.txt file with the compile and runtime dependencies, allowing the component to use it at runtime:

<plugin>
  <groupId>org.talend.sdk.component</groupId>
  <artifactId>talend-component-maven-plugin</artifactId>
  <version>${component.version}</version>
  <executions>
    <execution>
      <id>talend-dependencies</id>
      <goals>
        <goal>dependencies</goal>
      </goals>
    </execution>
  </executions>
</plugin>

Validate

This goal helps you validate the common programming model of the component. To activate it, you can use following execution definition:

<plugin>
  <groupId>org.talend.sdk.component</groupId>
  <artifactId>talend-component-maven-plugin</artifactId>
  <version>${component.version}</version>
  <executions>
    <execution>
      <id>talend-component-validate</id>
      <goals>
        <goal>validate</goal>
      </goals>
    </execution>
  </executions>
</plugin>

It is bound to the process-classes phase by default. When executed, it performs several validations that can be disabled by setting the corresponding flags to false in the <configuration> block of the execution:

Name Description Default

validateInternationalization

Validates that resource bundles are presents and contain commonly used keys (for example, _displayName)

true

validateModel

Ensures that components pass validations of the ComponentManager and Talend Component runtime

true

validateSerializable

Ensures that components are Serializable. This is a sanity check, the component is not actually serialized here. If you have a doubt, make sure to test it. It also checks that any @Internationalized class is valid and has its keys.

true

validateMetadata

Ensures that components have an @Icon and a @Version defined.

true

validateDataStore

Ensures that any @DataStore defines a @HealthCheck.

true

validateComponent

Ensures that the native programming model is respected. You can disable it when using another programming model like Beam.

true

validateActions

Validates action signatures for actions not tolerating dynamic binding (@HealthCheck, @DynamicValues, and so on). It is recommended to keep it set to true.

true

validateFamily

Validates the family by verifying that the package containing the @Components has a @Icon property defined.

true

validateDocumentation

Ensures that all components and @Option properties have a documentation using the @Documentation property.

true

validateLayout

Ensures that the layout is referencing existing options and properties.

true

validateOptionNames

Ensures that the option names are compliant with the framework. It is highly recommended and safer to keep it set to true.

true

Documentation

This goal generates an Asciidoc file documenting your component from the configuration model (@Option) and the @Documentation property that you can add to options and to the component itself.

<plugin>
  <groupId>org.talend.sdk.component</groupId>
  <artifactId>talend-component-maven-plugin</artifactId>
  <version>${component.version}</version>
  <executions>
    <execution>
      <id>talend-component-documentation</id>
      <goals>
        <goal>asciidoc</goal>
      </goals>
    </execution>
  </executions>
</plugin>
Name Description Default

level

Level of the root title.

2 (==)

output

Output folder path. It is recommended to keep it to the default value.

${classes}/TALEND-INF/documentation.adoc

formats

Map of the renderings to do. Keys are the format (pdf or html) and values the output paths.

-

attributes

Map of asciidoctor attributes when formats is set.

-

templateDir / templateEngine

Template configuration for the rendering.

-

title

Document title.

${project.name}

attachDocumentations

Allows to attach (and deploy) the documentations (.adoc, and formats keys) to the project.

true
If you use the plugin as an extension, you can add the talend.documentation.htmlAndPdf property and set it to true in your project to automatically get HTML and PDF renderings of the documentation.

Rendering your documentation

To render the generated documentation in HTML or PDF, you can use the Asciidoctor Maven plugin (or Gradle equivalent). You can configure both executions if you want both HTML and PDF renderings.

Make sure to execute the rendering after the documentation generation.

HTML rendering

If you prefer a HTML rendering, you can configure the following execution in the asciidoctor plugin. The example below:

  1. Generates the components documentation in target/classes/TALEND-INF/documentation.adoc.

  2. Renders the documentation as an HTML file stored in target/documentation/documentation.html.

<plugin> (1)
  <groupId>org.talend.sdk.component</groupId>
  <artifactId>talend-component-maven-plugin</artifactId>
  <version>${talend-component-kit.version}</version>
  <executions>
    <execution>
      <id>documentation</id>
      <phase>prepare-package</phase>
      <goals>
        <goal>asciidoc</goal>
      </goals>
    </execution>
  </executions>
</plugin>
<plugin> (2)
  <groupId>org.asciidoctor</groupId>
  <artifactId>asciidoctor-maven-plugin</artifactId>
  <version>1.5.6</version>
  <executions>
    <execution>
      <id>doc-html</id>
      <phase>prepare-package</phase>
      <goals>
        <goal>process-asciidoc</goal>
      </goals>
      <configuration>
        <sourceDirectory>${project.build.outputDirectory}/TALEND-INF</sourceDirectory>
        <sourceDocumentName>documentation.adoc</sourceDocumentName>
        <outputDirectory>${project.build.directory}/documentation</outputDirectory>
        <backend>html5</backend>
      </configuration>
    </execution>
  </executions>
</plugin>

PDF rendering

If you prefer a PDF rendering, you can configure the following execution in the asciidoctor plugin:

<plugin>
  <groupId>org.asciidoctor</groupId>
  <artifactId>asciidoctor-maven-plugin</artifactId>
  <version>1.5.6</version>
  <executions>
    <execution>
      <id>doc-html</id>
      <phase>prepare-package</phase>
      <goals>
        <goal>process-asciidoc</goal>
      </goals>
      <configuration>
        <sourceDirectory>${project.build.outputDirectory}/TALEND-INF</sourceDirectory>
        <sourceDocumentName>documentation.adoc</sourceDocumentName>
        <outputDirectory>${project.build.directory}/documentation</outputDirectory>
        <backend>pdf</backend>
      </configuration>
    </execution>
  </executions>
  <dependencies>
    <dependency>
      <groupId>org.asciidoctor</groupId>
      <artifactId>asciidoctorj-pdf</artifactId>
      <version>1.5.0-alpha.16</version>
    </dependency>
  </dependencies>
</plugin>

Including the documentation into a document

If you want to add some more content or a title, you can include the generated document into another document using Asciidoc include directive.

For example:

= Super Components
Super Writer
:toc:
:toclevels: 3
:source-highlighter: prettify
:numbered:
:icons: font
:hide-uri-scheme:
:imagesdir: images

include::{generated_doc}/documentation.adoc[]

To be able to do that, you need to pass the generated_doc attribute to the plugin. For example:

<plugin>
  <groupId>org.asciidoctor</groupId>
  <artifactId>asciidoctor-maven-plugin</artifactId>
  <version>1.5.6</version>
  <executions>
    <execution>
      <id>doc-html</id>
      <phase>prepare-package</phase>
      <goals>
        <goal>process-asciidoc</goal>
      </goals>
      <configuration>
        <sourceDirectory>${project.basedir}/src/main/asciidoc</sourceDirectory>
        <sourceDocumentName>my-main-doc.adoc</sourceDocumentName>
        <outputDirectory>${project.build.directory}/documentation</outputDirectory>
        <backend>html5</backend>
        <attributes>
          <generated_adoc>${project.build.outputDirectory}/TALEND-INF</generated_adoc>
        </attributes>
      </configuration>
    </execution>
  </executions>
</plugin>

This is optional but allows to reuse Maven placeholders to pass paths, which can be convenient in an automated build.

You can find more customization options on Asciidoctor website.

Testing a component web rendering

Testing the rendering of your component configuration into the Studio requires deploying the component in Talend Studio. Refer to the Studio documentation.

In the case where you need to deploy your component into a Cloud (web) environment, you can test its web rendering by using the web goal of the plugin:

  1. Run the mvn talend-component:web command.

  2. Open the following URL in a web browser: localhost:8080.

  3. Select the component form you want to see from the treeview on the left. The selected form is displayed on the right.

Two parameters are available with the plugin:

Make sure to install the artifact before using this command because it reads the component JAR from the local Maven repository.

Generating inputs or outputs

The Mojo generate (Maven plugin goal) of the same plugin also embeds a generator that you can use to bootstrap any input or output component:

<plugin>
  <groupId>org.talend.sdk.component</groupId>
  <artifactId>talend-component-maven-plugin</artifactId>
  <version>${talend-component.version}</version>
  <executions>
    <execution> (1)
      <id>generate-input</id>
      <phase>generate-sources</phase>
      <goals>
        <goal>generate</goal>
      </goals>
      <configuration>
        <type>input</type>
      </configuration>
    </execution>
    <execution> (2)
      <id>generate-output</id>
      <phase>generate-sources</phase>
      <goals>
        <goal>generate</goal>
      </goals>
      <configuration>
        <type>output</type>
      </configuration>
    </execution>
  </executions>
</plugin>
1 The first execution generates an input (partition mapper + emitter).
2 the second execution generates an output.

It is intended to be used from the command line (or IDE Maven integration) as follows:

$ mvn talend-component:generate \
    -Dtalend.generator.type=[input|output] \ (1)
    [-Dtalend.generator.classbase=com.test.MyComponent] \ (2)
    [-Dtalend.generator.family=my-family] \ (3)
    [-Dtalend.generator.pom.read-only=false] (4)
1 Select the type of component you want: input to generate a mapper and an emitter, or output to generate an output processor.
2 Set the class name base (automatically suffixed by the component type). If not set, the package is guessed and the classname is based on the basedir name.
3 Set the component family to use. If not specified, it defaults to the basedir name and removes "component[s]" from it. for example, my-component leads to my as family, unless it is explicitly set.
4 Specify if the generator needs to add component-api to the POM, if not already there. If you already added it, you can set it to false directly in the POM.

For this command to work, you need to register the plugin as follows:

<plugin>
  <groupId>org.talend.sdk.component</groupId>
  <artifactId>talend-component-maven-plugin</artifactId>
  <version>${talend-component.version}</version>
</plugin>

Talend Component Archive

Component ARchive (.car) is the way to bundle a component to share it in the Talend ecosystem. It is a plain Java ARchive (.jar) containing a metadata file and a nested Maven repository containing the component and its depenencies.

mvn talend-component:car

This command creates a .car file in your build directory. This file can be shared on Talend platforms.

This CAR is executable and exposes the studio-deploy command which takes a Talend Studio home path as parameter. When executed, it installs the dependencies into the Studio and registers the component in your instance. For example:

# for a studio
java -jar mycomponent.car studio-deploy /path/to/my/studio
or
java -jar mycomponent.car studio-deploy --location /path/to/my/studio

# for a m2 provisioning
java -jar mycomponent.car maven-deploy /path/to/.m2/repository
or
java -jar mycomponent.car maven-deploy --location /path/to/.m2/repository

You can also upload the dependencies to your Nexus server using the following command:

java -jar mycomponent.car deploy-to-nexus --url <nexus url> --repo <repository name> --user <username> --pass <password> --threads <parallel threads number> --dir <temp directory>

In this command, Nexus URL and repository name are mandatory arguments. All other arguments are optional. If arguments contain spaces or special symbols, you need to quote the whole value of the argument. For example:

--pass "Y0u will \ not G4iess i' ^"

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