Add `build` or `prepare` command to processes

[tqwewe]

Feature Request

Add a build or prepare field to processes for running building a process before running it.

Use Case:

Many processes when working with Rust need to be built before running. Health-checks don't play nicely with this when the process takes a while to build. Having processes be able to be built with an arbitrary command, which health checks wait for would be ideal.

processes:
  http_server:
    build: cargo build -p http_server # alternatively could be named `prepare`
    command: ./target/debug/http_server
    readiness_probe: ...
    liveness_probe: ...

Who Benefits From The Change(s)?

People working with compiled languages such as Rust, C, etc.

Alternative Approaches

Make health checks retry continuously, though this is not ideal.

[F1bonacc1]

Hi @tqwewe,

Thank you for this suggestion.
Have you considered adding a build step as a dependency process to your main http_server process?

processes:
  http_server:
    command: ./target/debug/http_server
    depends_on:
      build_http_server:
        condition: process_completed_successfully
  
  build_http_server:
    command: cargo build -p http_server

[joetifa2003]

Hi @F1bonacc1

I'm using the dependency approach, but one thing that i miss is tracking of source file checksum to decide whether to build or not.

For example whether or not to build vite production bundle if source changes.

Currently the approach for this is to use another tool like Taskfile which has this feature, and call it from within process compose.

It would be great for it to be builtin.

[adrian-gierakowski]

Hi @F1bonacc1

I'm using the dependency approach, but one thing that i miss is tracking of source file checksum to decide whether to build or not.

For example whether or not to build vite production bundle if source changes.

Currently the approach for this is to use another tool like Taskfile which has this feature, and call it from within process compose.

It would be great for it to be builtin.

I recommend using nix with https://github.com/Platonic-Systems/process-compose-flake
And maybe also:
https://github.com/juspay/services-flake