_skaffold-init task multimodule logic issues

[balopat]

The issues with the current logic (at least in the maven plugin, gradle task might have the same issues):

• when a submodule has a different parent specified (e.g. spring boot starter pom) then our current logic fails to set the project id as the parent comes back as null in the InitMojo - this creates issues in multimodule projects (e.g. the Cloud Code java guestbook sample) because the listed projects don't have anything in them
• I'm not sure how frequent nested modules are but currently we don't handle those well either
• we are using the artifactId instead of the module name to return a project which is a problem as that is interpreted on the skaffold side as a directory

I won't have time to fully implement the thing with tests and everything, but as I played around with the code this seemed to do the job altogether:

@Mojo(name = InitMojo.GOAL_NAME, requiresDependencyCollection = ResolutionScope.NONE)
public class InitMojo extends JibPluginConfiguration {

  @VisibleForTesting static final String GOAL_NAME = "_skaffold-init";

  @Override
  public void execute() throws MojoExecutionException {
    checkJibVersion();
    MavenProject project = getProject();
    MavenProject topLevelProject = getSession().getTopLevelProject();
    if (!project.equals(topLevelProject)) {
      return;
    }

    if (isParentProject(project)) {
      Set<MavenProject> projects = collectLeafProjects(project);
      for (MavenProject p : projects) {
        print(p, true);
      }
    } else {
      print(project, false);
    }
  }

  private Set<MavenProject> collectLeafProjects(MavenProject project) {
    Set<MavenProject> projects = new HashSet<>();
    for (MavenProject p : project.getCollectedProjects()) {
      if (isParentProject(p)) {
        projects.addAll(collectLeafProjects(p));
      } else {
        projects.add(p);
      }
    }
    return projects;
  }

  private boolean isParentProject(MavenProject project) {
    return project.getPackaging().equals("pom") && project.getModules().size() > 0;
  }

  private void print(MavenProject project, boolean setProject) throws MojoExecutionException {
    SkaffoldInitOutput skaffoldInitOutput = new SkaffoldInitOutput();
    skaffoldInitOutput.setImage(getTargetImage());
    if (setProject) {
      skaffoldInitOutput.setProject(project.getGroupId() + ":" + project.getArtifactId());
    }
    System.out.println();
    System.out.println("BEGIN JIB JSON");
    try {
      System.out.println(skaffoldInitOutput.getJsonString());
    } catch (IOException ex) {
      throw new MojoExecutionException(ex.getMessage(), ex);
    }
  }
}

[chanseokoh]

Don't forget to check GoogleContainerTools/skaffold#2844

[TadCordle]

This seems like an improvement, but the problem now is that when the goal runs on a multi-module project, the goal runs on all of the sub-modules first before running on the parent. This means for the java-guestbook sample, which has a frontend and backend module, we get output like the following:

$ ./mvnw jib:_skaffold-init

// frontend prints
BEGIN JIB JSON
{}

// backend prints
BEGIN JIB JSON
{}

// parent prints
BEGIN JIB JSON
{"project":"org.springframework.boot:backend"}

BEGIN JIB JSON
{"project":"org.springframework.boot:frontend"}

I think the intended behavior is to only print the last 2 JSON structs, correct? It seems like the topLevelProject check at the top doesn't work.

[loosebazooka]

should we force it to only run on the parent?

[TadCordle]

Actually, my mistake. Was running the wrong version of Jib on the submodules. It looks like this does work.

[jonjohnsonjr]

For posterity, I'll chime in to say my issue is now fixed.

Before

$ skaffold init --XXenableJibInit --analyze | jq .
{
  "builders": [
    {
      "name": "Jib Maven Plugin",
      "payload": {
        "path": "pom.xml"
      }
    },
    {
      "name": "Jib Maven Plugin",
      "payload": {
        "path": "pom.xml"
      }
    },
    {
      "name": "Docker",
      "payload": {
        "path": "backend/Dockerfile"
      }
    },
    {
      "name": "Docker",
      "payload": {
        "path": "frontend/Dockerfile"
      }
    }
  ],
  "images": [
    {
      "name": "java-guestbook-backend",
      "foundMatch": false
    },
    {
      "name": "java-guestbook-frontend",
      "foundMatch": false
    },
    {
      "name": "mongo",
      "foundMatch": false
    }
  ]
}

After

$ skaffold init --XXenableJibInit --analyze | jq .
{
  "builders": [
    {
      "name": "Jib Maven Plugin",
      "payload": {
        "path": "pom.xml",
        "project": "org.springframework.boot:frontend"
      }
    },
    {
      "name": "Jib Maven Plugin",
      "payload": {
        "path": "pom.xml",
        "project": "org.springframework.boot:backend"
      }
    },
    {
      "name": "Docker",
      "payload": {
        "path": "backend/Dockerfile"
      }
    },
    {
      "name": "Docker",
      "payload": {
        "path": "frontend/Dockerfile"
      }
    }
  ],
  "images": [
    {
      "name": "java-guestbook-backend",
      "foundMatch": false
    },
    {
      "name": "java-guestbook-frontend",
      "foundMatch": false
    },
    {
      "name": "mongo",
      "foundMatch": false
    }
  ]
}

[chanseokoh]

@balopat @jonjohnsonjr we've released Jib 2.1.0, which fixes this issue.