Poetry Run Cloud Native Buildpack

gcr.io/paketo-buildpacks/poetry-run

The Paketo Poetry Run CNB sets the start command for a given poetry application.

This buildpack detects when one of the following conditions is met:

1. BP_POETRY_RUN_TARGET is set

   Example: BP_POETRY_RUN_TARGET=default_app.server:run. The resulting start command for this example would be poetry run default_app.server:run.

2. pyproject.toml exists and contains exactly one poetry script

   More specifically, the buildpack will detect if pyproject.toml looks like the following:

[tool.poetry.scripts]
some-script = "some.module:some_method"

The resulting start command for this example would be poetry run some-script.

See the poetry run documentation for more information.

Integration

This buildpacks writes a start command, so currently there is no conceivable reason to require it as a dependency.

Usage

To package this buildpack for consumption:

$ ./scripts/package.sh --version <version-number>

This will create a buildpackage.cnb file under the build directory which you can use to build your app as follows:

pack build <app-name> -p <path-to-app> \
  -b <path/to/cpython.cnb> \
  -b <path/to/pip.cnb> \
  -b <path/to/poetry.cnb> \
  -b <path/to/poetry-install.cnb> \
  -b build/buildpackage.cnb

Configuration

Custom run command

This buildpack will set a start command that begins with poetry run. This can be set using BP_POETRY_RUN_TARGET and can reference either a script key from pyproject.toml or an executable on the file system. See the poetry run documentation for more information.

Enabling reloadable process types

You can configure this buildpack to wrap the entrypoint process of your app such that it kills and restarts the process whenever files change in the app's working directory in the container. With this feature enabled, copying new versions of source code into the running container will trigger your app's process to restart. Set the environment variable BP_LIVE_RELOAD_ENABLED=true at build time to enable this feature.

Run Tests

To run all unit tests, run:

./scripts/unit.sh

To run all integration tests, run:

/scripts/integration.sh

Known issues and limitations

• When BP_POETRY_RUN_TARGET is not set, only one (and exactly one) script may be defined in the pyproject.toml file. Zero scripts, or multiple scripts, will result in the buildpack failing detection and therefore not participating in the order group.