Pipenv Cloud Native Buildpack

The Paketo Buildpack for Pipenv is a Cloud Native Buildpack that installs pipenv into a layer and makes it available on the PATH.

The buildpack is published for consumption at gcr.io/paketo-buildpacks/pipenv.

Behavior

This buildpack always participates.

The buildpack will do the following:

• At build time:
  • Contributes the pipenv binary to a layer
  • Prepends the pipenv layer to the PYTHONPATH
  • Adds the newly installed pipenv location to PATH
• At run time:
  • Does nothing

Configuration

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

Integration

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

[[requires]]

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

  # The version of the Pipenv dependency is not required. In the case it
  # is not specified, the buildpack will provide the default version, which can
  # be seen in the buildpack.toml file.
  # If you wish to request a specific version, the buildpack supports
  # specifying a semver constraint in the form of "2018.*", "2018.11.*", or even
  # "2018.11.26".
  version = "2018.11.26"

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

    # Setting the build flag to true will ensure that the Pipenv
    # depdendency is available on the $PATH for subsequent buildpacks during
    # their build phase. If you are writing a buildpack that needs to run Pipenv
    # during its build process, this flag should be set to true.
    build = true

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

Limitations

This buildpack requires internet connectivity to install pipenv. Installation in an air-gapped environment is not supported.

The dependency URL metadata contained in buildpack.toml is not actually used, as pipenv is installed directly from the internet. However, the rest of the depedency metadata is used (e.g. for generating an SBOM). This will be addressed in upcoming work which will change the way dependencies are consumed by buildpacks.

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 <cpython-buildpack> -b <pip-buildpack> -b build/buildpackage.cnb -b <some-pipenv-consumer-buildpack>.

To run the unit and integration tests for this buildpack:

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