Hi everyone 🙂 I am trying to figure out how to effectively use internal libraries in our Python monorepo, and running into some problems. I think Pants might be able to solve them but I'm not sure where to begin. For context, my layout looks like this:

.
└── monorepo/
    ├── .github/
    │   └── workflows/
    │       ├── build_app1.yaml
    │       └── build_app2.yaml
    ├── app/
    │   ├── app1/
    │   │   ├── app1/
    │   │   │   └── __init__.py
    │   │   ├── Dockerfile
    │   │   ├── pyproject.toml
    │   │   └── poetry.lock
    │   └── app2/
    │       ├── app2/
    │       │   └── __init__.py
    │       ├── Dockerfile
    │       ├── pyproject.toml
    │       └── poetry.lock
    └── lib/
        └── lib1/
            ├── lib1/
            │   └── __init__.py
            ├── pyproject.toml
            └── poetry.lock

A lot can depend on the details of your project, but I would suggest reading through this: https://www.pantsbuild.org/blog/2021/10/13/pants-pex-and-docker#deploying-pex-files-in-your-docker-images Its what got me started with pants. The pattern that's working for us is something like this: • Set up your source roots (https://www.pantsbuild.org/stable/docs/using-pants/key-concepts/source-roots has some examples for how to do this for various project structures) • Set up your IDE https://www.pantsbuild.org/stable/docs/using-pants/setting-up-an-ide (to make sure your dev environment can understand/follow your source roots setup) • Then, you'll have a bunch of

python_source

targets (whether libs or app files mostly doesn't matter too much) • Create a

pex_binary

target that specifies the entrypoint file for your code • In your dockerfile,

COPY

the pex file (from

/dist/something/whatever.pex

which is where the build artifact ends up) • Now, when you do

pants package /path/to/app1:app1_docker_image

(I made up a path/target name here). Pants will use its dependency inference techniques to find every python file depended on by your

app1_entrypoint.py

(that you used for the

pex_binary

), build them into an executable pex file, and copy them into your dockerfile.

Thank you, this was very helpful!