Add JAVA_ARGS to support command line arguments

[rhuss]

This is related to https://issues.jboss.org/projects/OSFUSE/issues/OSFUSE-475 to transport command line arguments to the run s2i script.

[LarsMilland]

Hi

I have just recently looked for a way to inject commandline arguments to s2i script /usr/local/s2i/run, exactly for the use case as how to choose which profile of a Spring Boot application to launch.

I think that if just the run script was extended with parsing on its own arguments then one could just change the Docker image launch configuration in the containers segment of a related resource fragment or a fully OpenShift/Kubernetes DepoymentController/ReplicationController manifest.

So if the script would just do:

exec /opt/run-java/run-java.sh $*
instead of just:
exec /opt/run-java/run-java.sh

Or with the actually already specified/documented way as environment variable JAVA_MAIN_ARGS (though not actually working):

spec:
  replicas: ${replicas}
  template:
    spec:
      volumes:
        - name: secrets-volume
          secret:
            secretName: datasource-secrets
      containers:
      - volumeMounts:
        - name: secrets-volume
          mountPath: /etc/secrets
        args:
          - /usr/local/s2i/run
          - "${appargs}"
        env:
          - name: JAVA_OPTIONS
            value: ${javaoptions}
          - name: JAVA_MAIN_ARGS
            value: ${appargs}

Best regards
Lars Milland

[rhuss]

I agree that we should support both:

• If arguments are given to the script, then use these first.
• In addition, if the env var "JAVA_ARGS" is provided, then append these arguments, too.

The problem with the env approach of course is how to deal with arguments containing spaces. The best would be to expand the variable and then eval everything in the startup script, so that we leave this to the shell.