Apache OpenWhisk runtime for Java language functions. https://openwhisk.apache.org/
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README.md

Apache OpenWhisk runtimes for java

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Quick Java Action

A Java action is a Java program with a method called main that has the exact signature as follows:

public static com.google.gson.JsonObject main(com.google.gson.JsonObject);

For example, create a Java file called Hello.java with the following content:

import com.google.gson.JsonObject;

public class Hello {
    public static JsonObject main(JsonObject args) {
        String name = "stranger";
        if (args.has("name"))
            name = args.getAsJsonPrimitive("name").getAsString();
        JsonObject response = new JsonObject();
        response.addProperty("greeting", "Hello " + name + "!");
        return response;
    }
}

In order to compile, test and archive Java files, you must have a JDK 8 installed locally.

Then, compile Hello.java into a JAR file hello.jar as follows:

javac Hello.java
jar cvf hello.jar Hello.class

Note: google-gson must exist in your Java CLASSPATH when compiling the Java file.

You need to specify the name of the main class using --main. An eligible main class is one that implements a static main method as described above. If the class is not in the default package, use the Java fully-qualified class name, e.g., --main com.example.MyMain.

If needed you can also customize the method name of your Java action. This can be done by specifying the Java fully-qualified method name of your action, e.q., --main com.example.MyMain#methodName

Create the Java Action

To use as a docker action:

wsk action update helloJava hello.jar --main Hello --docker openwhisk/java8action

This works on any deployment of Apache OpenWhisk

To use on a deployment of OpenWhisk that contains the runtime as a kind:

wsk action update helloJava hello.jar --main Hello --kind java:8

Invoke the Java Action

Action invocation is the same for Java actions as it is for Swift and JavaScript actions:

wsk action invoke --result helloJava --param name World
  {
      "greeting": "Hello World!"
  }

Local development

./gradlew core:java8:distDocker

This will produce the image whisk/java8action

Build and Push image

docker login
./gradlew core:java8:distDocker -PdockerImagePrefix=$prefix-user -PdockerRegistry=docker.io

Deploy OpenWhisk using ansible environment that contains the kind java:8 Assuming you have OpenWhisk already deploy localy and OPENWHISK_HOME pointing to root directory of OpenWhisk core repository.

Set ROOTDIR to the root directory of this repository.

Redeploy OpenWhisk

cd $OPENWHISK_HOME/ansible
ANSIBLE_CMD="ansible-playbook -i ${ROOTDIR}/ansible/environments/local"
$ANSIBLE_CMD setup.yml
$ANSIBLE_CMD couchdb.yml
$ANSIBLE_CMD initdb.yml
$ANSIBLE_CMD wipe.yml
$ANSIBLE_CMD openwhisk.yml

Or you can use wskdev and create a soft link to the target ansible environment, for example:

ln -s ${ROOTDIR}/ansible/environments/local ${OPENWHISK_HOME}/ansible/environments/local-java
wskdev fresh -t local-java

Testing

Install dependencies from the root directory on $OPENWHISK_HOME repository

pushd $OPENWHISK_HOME
./gradlew install
podd $OPENWHISK_HOME

Using gradle to run all tests

./gradlew :tests:test

Using gradle to run some tests

./gradlew :tests:test --tests *ActionContainerTests*

Using IntelliJ:

  • Import project as gradle project.
  • Make sure working directory is root of the project/repo

Using container image to test

To use as docker action push to your own dockerhub account

docker tag whisk/java8action $user_prefix/java8action
docker push $user_prefix/java8action

Then create the action using your the image from dockerhub

wsk action update helloJava hello.jar --main Hello --docker $user_prefix/java8action

The $user_prefix is usually your dockerhub user id.

License

Apache 2.0

Disclaimer

Apache OpenWhisk Runtime Java is an effort undergoing incubation at The Apache Software Foundation (ASF), sponsored by the Apache Incubator. Incubation is required of all newly accepted projects until a further review indicates that the infrastructure, communications, and decision making process have stabilized in a manner consistent with other successful ASF projects. While incubation status is not necessarily a reflection of the completeness or stability of the code, it does indicate that the project has yet to be fully endorsed by the ASF.