Zip up dependencies?

[nilskp]

Is there an existing task to zip up all the dependencies? And if not, what's the cleanest way to achieve this?

[lihaoyi]

You aren't giving a lot of information to go on, but JavaModule#upstreamAssembly sounds like something you may want

[nilskp]

I simply want to collect all the dependency jars into a zip file for easy distribution. I'm kinda surprised that task isn't already present.

[lefou]

Probably, because this is not standard. There are so many potential layouts and dependency sets and there is no established default, since there is also no known toolchain relying on such zip files. Often, plugins for other build tools creating such archives are highly configurable and typically don't produce useful results out of the box.

In Mill, it's already easy to programmatically get the desired dependencies and to use os-lib for zip file handling. E.g. to get all external runtime-dependencies,

1. you can use the resolvedRunMvnDeps task, which returns a Seq[PathRef],
2. use os-lib's os.zip to create the zip file
3. (optional) if you also want to publish the zip file, override PublishModule.extraPublish and provide the specific details such as the classifier

These three steps are typically not more complicated than configuring a dedicated plugin.

It may look like this (I haven't tested it):

def runtimeDepsZip = Task {
  val jars = resolvedRunMvnDeps().map(_.path)
  val zip = Task.dest / "deps.zip"
  os.zip(destination = zip, sourcePaths = jars)
  PathRef(zip)
}

override def extraPublish = Task {
  Seq(PublishInfo(file = runtimeDepsZip(), classifier = Some("dependencies"), ext = "zip"))
}

[nilskp]

Thanks, I'll take a look.

There are so many potential layouts and dependency sets

What do you mean by this? The build script, whether Maven, Gradle, SBT, or Mill, defines the external dependencies, those that need to be included in the CP at runtime. This is well-defined, no? I'm also not sure what you mean by "layouts".

EDIT: Ok, I guess by "layouts" you mean the dir structure in the zip file? I really just need a single file that can be copied easily and then unpacked into a single dir, so it's easy to include in the classpath with -cp dir/*. Besides using a fat jar (which I consider an anti-pattern), are there other ways?

[lefou]

There are a lot of movable parts:

• dependencies sets: runtime, compile-time, provided, optional, non redistributable, non-external (artifacts produced by a multi-project), exploded jars, ...
• layouts: flat, sub-dirs, Maven repo structure, ...
• naming of the jars, naming collisions, ...

I'd also consider the assembly produced by AssemblyModule, although convenient, an anti-pattern. Especially the fact, that you mix or merge files from different jars, which might come with different licenses, is problematic. Some of these issues are addressed by the RepackageModule, but there are always trade-offs.