Contributor guide

Prerequisites

  • git

  • GraalVM with native-image command installed and GRAALVM_HOME environment variable set, see Building a native executable section of the Quarkus documentation.

  • If your are on Linux, docker is sufficient for the native mode too. Use -Pnative,docker instead of -Pnative if you choose this option.

  • Java 8

  • Maven 3.5.3+ (unless you use the Maven Wrapper, a.k.a. mvnw available in the source tree).

How to build

Checkout the code

$ git clone https://github.com/apache/camel-quarkus.git
$ cd camel-quarkus

A fast build without tests:

$ mvn clean install -DskipTests

A build with integration tests in the JVM mode only:

$ mvn clean install

A build with integration tests in both the JVM mode and the native mode:

$ mvn clean install -Pnative

Create a new extension

  1. You should know how to build.

  2. Go through the Quarkus extension author’s guide to get an idea what is expecting you.

  3. Make sure that nobody else works on the same extension already by searching through the GitHub issues.

  4. Let others know that you work on the given extension by either creating a new issue or asking to assign an existing one to you.

  5. Scaffold the necessary Maven modules using quarkus-maven-plugin. As an example let’s add a new extension for supporting an imaginary Camel component foo-abc:

    $ cd camel-quarkus
    $ cd extensions
    $ mvn quarkus:create-extension -N \
        -Dquarkus.artifactIdBase=foo-abc \
        -Dquarkus.nameBase="Foo ABC"

    where:

    • foo-abc is the unique part of the new extension’s artifactId without the camel-quarkus- prefix

    • Foo ABC is the unique part of the artifact name without the `Camel Quarkus :: ` prefix

      The artifactId and artifact name prefixes and suffixes are added automatically by the plugin.

      The above sequence of commands does the following:

    • It creates three new Maven modules under the extensions directory: camel-quarkus-foo-abc-parent, camel-quarkus-foo-abc (a.k.a. the runtime module) and camel-quarkus-foo-abc-deployment.

    • These three modules are linked where necessary:

      • camel-quarkus-foo-abc-parent is added to the <modules> of camel-quarkus-extensions

      • camel-quarkus-foo-abc is added to the <dependencyManagement> of the runtime BOM (Bill of Materials) poms/bom/pom.xml

      • camel-quarkus-foo-abc-deployment is added to the <dependencyManagement> of the deployment BOM (Bill of Materials) poms/bom-deployment/pom.xml

    • It creates a basic FooAbcProcessor class in the deployment module.

    • It also creates a stub of an integration test module under integration-tests/foo-abc.

      A compilation performed immediately after generating the modules should pass flawlessly but running the tests will fail because the test project needs to get finished. You need to build poms/bom and poms/bom-deployment one time first.

      The nameBase parameter of the mojo is optional. If you do not specify it on the command line, the plugin will derive it from artifactIdBase by replacing dashes with spaces and capitalizing the first letter of each token. So you may consider omitting explicit nameBase in some cases.
  6. Create extensions/foo-abc/runtime/src/main/resources/META-INF/quarkus-extension.yaml. Consult other existing extensions for the content of the file.

  7. Complete the extension by adding dependencies to the runtime module. You probably want to add a dependency on on the given Camel component - in our case org.apache.camel:camel-foo-abc.

  8. Complete the integration test module under integration-tests/foo-abc. Make sure you test both the consumer and the producer of the component (if the component supports both). Make sure the tests are passing both in the JVM mode (mvn test) and in the native mode (mvn verify -Pnative).

  9. In case of problems, consult the Quarkus extension author’s guide, ask for help in the given GitHub issue or via Camel Quarkus chat.

  10. If the usage of your new extension differs from the usage of the given Camel component, please add an AsciiDoc page under docs/modules/ROOT/pages/extensions and document the differences and Quarkus specific configuration options there. For our imaginary Camel component foo-abc the complete path of the page would be docs/modules/ROOT/pages/extensions/foo-abc.adoc. After completing the page, run mvn clean install -DskipTests from the root of the source tree to add your extension to the autogenerated list of extensions.

  11. Before sending a pull request, please make sure you have done the following:

    • Run mvn license:format -Plicense to add license headers to the new files.

    • Run mvn process-resources to re-generate the list of extensions and the Camel Quarkus Catalog

    • Squash your commits

Good luck!