How do I build a component that uses proto-lens-protoc?

[lally]

Hi, this is a post-to-the-right-project move of input-output-hk/stack2nix#170 -- I had a stack project that used proto-lens-protoc, and there are both haskell packages and top-level nix packages for this.

I frankly don't care if the solution is hacky, but what's the simplest (to do now, to keep working later) method of getting my proto's sorted for my package? The custom setup used /just/ generates haskell from the .proto files. So any invocation of the protoc compiler that results in the files being in a place that's accessible (and not in my src/ directory, where version control's an issue) for compilation is fine by me.

[timbess]

I'm also interested in this. It seems to pull down proto-lens-protoc but fails to build because protoc is not in the PATH. Is there a way I can override the buildInputs for proto-lens-protoc to include pkgs.protobuf?

[michaelpj]

If your setup doesn't declare that it needs the exectuable in question (which is the case for proto-lens-protoc), then you need to get the executable onto the path for every place where the setup runs, i.e. the configure phase for each component.

You can do this by setting build-tools for each component (sadly there isn't a way to set it for all components at the moment). Here's an example of me doing this in order to get a suitable agda in scope for a custom setup that uses it to generate Haskell sources.

A package-level build-tools option would probably be helpful for cases like this.

[timbess]

@michaelpj Thanks! That's a great fleshed out example of a more complex build. Would be awesome to see an example like that in the docs.

[michaelpj]

For sure, we could document this better (although I'm reluctant to add more big examples until we fix #518).

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.