Feature Dependencies - installsAfter not respected

Hello,

I’ve written a couple of features for a project I’m working on and I’ve ran into situations where I’m not sure what the best approach to take is.

For example, I have a feature which involves installing a CLI tool using npm. Now, I’m not sure whether this feature should also install Node.js so that it is able to install the CLI tool, since I have no control over the base image, nor the included features in the devcontainer.json file.

The power of features, as I understand, is that they can be composed together; making each serve one purpose (installing the given feature) thus providing a simple way to handle all the tooling permutations for many different developers and/or teams whilst avoiding “golden container images”; and similar perhaps in concept to buildpacks.

So it occurred to me that since devcontainers/features already provide features for installing Node.js (and other language runtimes), it would be beneficial to make my feature dependant on the node feature. Then I wouldn’t need to worry about which base image a developer is using, and the node feature would be automatically included before mine, so my feature would install reliably.

Additional scenarios include:

• a Ruby gem which needs to build a native extension and thus requires build-essential to be installed.
• a Python package, installed via pip, needing to ensure Python and pip are installed.
• a Go CLI tool, which doesn’t have a binary distribution, installed using go install, needing go to be installed.
• a tflint ruleset for AWS, which requires Terraform and tflint to be installed.

I realise installing packages using a postCreateCommand script can work, but it places the onus on the developer to know what features to include to install the given package. For example, I’m building features which install Python packages (e.g. mkdocs) for C# .Net developers, who wouldn’t know to include the python feature.

I imagine a devcontainer-feature.json file including a dependsOn property, in the same schema as the devcontainer.json features object.

I.e.

"dependsOn": {
  "ghcr.io/user/repo/go": {},
  "ghcr.io/user/repo1/go:1": {},
  "ghcr.io/user/repo2/go:latest": {},
  "https://github.com/user/repo/releases/devcontainer-feature-go.tgz": { 
        "optionA": "value" 
  },
  "./myGoFeature": { 
        "optionA": true,
        "optionB": "hello",
        "version" : "1.0.0"
  }
}

[edgonmsft]

Awesome! Keep the feedback coming!

[virtualstaticvoid]

Hi @edgonmsft

Okay, I’ve updated my test repo with the changes to installsAfter and to use a global scenario test as mentioned above.

🎉 The global scenario test is passing now; installing the python feature dependency prior to running the “pip” test.

Thanks!