Project dependencies in a separate layer for WAR projects

[chanseokoh]

We put project dependencies into a separate layer for JAR projects (#1436 (comment) and #403 (comment)), but this isn't supported for WAR projects.

---

Note there are other related feature requests for generalized dependency control (such as excluding certain dependencies from a list and fine-controlled dependency layering):

#1962 (comment)
#403 (comment)
#403 (comment)
#403 (comment)
#403 (comment)
#1436 (comment)
#1852

Note we expect to support the generalized fined-grained dependency control through the Jib extension framework: #1962 (comment)

[ST-DDT]

I use jib-maven-plugin 2.2.0 and I have a separate layer for the dependencies.

    <packaging>war</packaging>

		}, {
			"created": "2020-05-13T13:36:58.743844200Z",
			"author": "Jib",
			"created_by": "jib-maven-plugin:2.2.0",
			"comment": "dependencies"
		}, {
			"created": "2020-05-13T13:36:58.743844200Z",
			"author": "Jib",
			"created_by": "jib-maven-plugin:2.2.0",
			"comment": "snapshot dependencies"
		}, {

Or I'm I mistaken?

[chanseokoh]

I was talking about "project dependencies", i.e., JAR from a sibling module/sub-project within the same project.

[Eveneko]

OK, I'll work on it. ;-)

[chanseokoh]

@Eveneko thank you very much! If you need any help, let us know.

I think it's not difficult to implement this on Maven. For a non-WAR project, we identify project dependencies in MavenProjectProperties.classifyDependencies() and put them into the project dependency layer by calling javaContainerBuilder.addProjectDependencies(). However, for a WAR project, we go through a different execution path with JavaContainerBuilderHelper.fromExplodedWar(), and the helper method doesn't call addProjectDependencies(). I think we can match project dependencies in a WAR file by checking the filename of the dependency JARs in webInfLib (WEB-INF/lib/*.jar).

[Eveneko]

@chanseokoh
Hi, I noticed that project dependencies are obtained by the following code in method createJibContainerBuilder in MavenProjectProperties.java:

session
    .getProjects()
    .stream()
    .map(MavenProject::getArtifact)
    .collect(Collectors.toSet())

I am not clear about MavenSession (try to find documents but failed )
I wonder if this is the same for war project to get project dependencies using MavenSession?

[chanseokoh]

@Eveneko
Hi! Yeah, What happens is that, session.getProjects() gives us all the projects (including the root POM project and all sub-modules) involved in an entire Maven build session, and calling getArtifact() on each project tells us the output artifact (e.g., a JAR file) associated with the project. For example, if a multi-module setup looks like this,

my-project: getArtifact() returns a no-file Artifact for the root project
  +-- library-foo-module: getArtifact() returns "library-foo-*.jar" (basically)
  +-- library-bar-module: getArtifact() returns "library-bar-*.jar"
  `-- main-app: (getArtifact() returns "main-app-*.jar", but we won't care)

then in classifyDependencies(), it goes through all the dependencies of main-app to check whether they are either library-foo-*.jar or library-foo-*.jar; if so, they are classified as a project dependency.

So the same story still applies to the WAR case, basically. The difference, however, would be that you may need to check actual filenames in WEB-INF/lib/*.jar to determine if a JAR file there is from a sub-module.

[WuYff]

Hi @chanseokoh, thank you for your guide. We created a pr and hope that you can review it. Working with @Eveneko.

[loosebazooka]

Thanks @WuYff for your contribution! This is released as part of jib 2.4.0.

[WuYff]

Thanks @chanseokoh @loosebazooka ! :)

[chanseokoh]

Note we expect to support the generalized fined-grained dependency control through the Jib extension framework: #1962 (comment)

The Jib Extension Framework is now available with the latest Jib versions. You can easily extend and tailor the Jib plugins behavior to your liking.

We've written a general-purpose layer-filter extension that enables fine-grained layer control, including deleting files and moving files into new layers.

• Maven Layer-Filter Extension
• Gradle Layer-Filter Extension

For general information about using and writing extensions, take a look at the Jib Extensions repo.