Poetry Cloud Native Buildpack

`gcr.io/paketo-buildpacks/poetry`

The Paketo Poetry Buildpack is a Cloud Native Buildpack that installs Poetry into a layer and places it on the PATH.

The buildpack is published for consumption at gcr.io/paketo-buildpacks/poetry and paketobuildpacks/poetry.

Behavior

This buildpack always participates.

The buildpack will do the following:

At build time:
- Contributes the poetry binary to a layer
- Prepends the poetry layer to the PYTHONPATH environment variable
- Adds the newly installed poetry location to the PATH environment variable
At run time:
- Does nothing

Configuration

Environment Variable	Description
`$BP_POETRY_VERSION`	Configure the version of Poetry to install. Buildpack releases (and the Poetry versions for each release) can be found here.

Integration

The Poetry CNB provides Poetry as a dependency. Downstream buildpacks can require the Poetry dependency by generating a Build Plan TOML file that looks like the following:

[[requires]]

  # The name of the Poetry dependency is "poetry". This value is considered
  # part of the public API for the buildpack and will not change without a plan
  # for deprecation.
  name = "poetry"

  # The version of the Poetry dependency is not required. In the case it
  # is not specified, the buildpack will select the latest supported version in
  # the buildpack.toml.
  # If you wish to request a specific version, the buildpack supports
  # specifying a semver constraint in the form of "21.*", "21.0.*", or even
  # "21.0.1".
  version = "21.0.1"

  # The Poetry buildpack supports some non-required metadata options.
  [requires.metadata]

    # Setting the build flag to true will ensure that the Poetry dependency is
    # available on the $PATH, and that $PYTHONPATH contains the path to `poetry` for
    # subsequent buildpacks during their build phase. If you are writing a
    # buildpack that needs to run Poetry during its build process, this flag should
    # be set to true.
    build = true

    # Setting the launch flag to true will ensure that the Poetry
    # dependency is available on the $PATH, and that $PYTHONPATH contains the
    # path to `poetry` for the running application. If you are writing an
    # application that needs to run Poetry at runtime, this flag should be set to
    # true.
    launch = true

Usage

To package this buildpack for consumption:

$ ./scripts/package.sh --version x.x.x

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 build/buildpackage.cnb -b <other-buildpacks..>.

To run the unit and integration tests for this buildpack:

$ ./scripts/unit.sh && ./scripts/integration.sh

Known issues and limitations

This buildpack does not work in an offline/air-gapped environement; it requires internet access to install poetry. The impact of this limitation is mitigated by the fact that poetry itself does not support vendoring of dependencies, and so cannot function in an offline/air-gapped environment.

TisVictress / poetry