Pipenv Install Cloud Native Buildpack

The Paketo Buildpack for Pipenv Install is a Cloud Native Buildpack that installs packages using pipenv and makes it available to the application.

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

Behavior

This buildpack participates if Pipfile exists at the root of the app.

The buildpack will do the following:

• Installs the application packages to a layer made available to the app.
• Prepends the layer site-packages onto PYTHONPATH.
• Prepends the layer's bin directory to the PATH.

This buildpack speeds up the build process by reusing (the layer of) installed packages from a previous build if it exists, and later cleaning up any unused packages. For apps that do not have a Pipfile.lock, clean-up is not performed to avoid the overhead of generating a lock file. Users of such apps should either include a lock file with their app, or clear their build cache during a rebuild to avoid any unused packages in the built image.

Integration

The Pipenv Install CNB provides site-packages as a dependency. Downstream buildpacks can require the site-packages dependency by generating a [Build Plan TOML] (https://github.com/buildpacks/spec/blob/master/buildpack.md#build-plan-toml) file that looks like the following:

[[requires]]

  # The name of the dependency provided by the Pipenv Install Buildpack is
  # "site-packages". This value is considered part of the public API for the
  # buildpack and will not change without a plan for deprecation.
  name = "site-packages"

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

    # Set the build flag to true to make the site-packages dependency available on the $PYTHONPATH/$PATH
    # for subsequent buildpacks during their build phase.
    build = true

    # Set the launch flag to true to make the site-packages dependency available on the $PYTHONPATH/$PATH
    # for the running application.
    launch = true

SBOM

This buildpack can generate a Software Bill of Materials (SBOM) for the dependencies of an application.

However, this feature only works if the application already has a Pipfile.lock file. This is due to a limitation in the upstream SBOM generation library (Syft).

Applications that declare their dependencies via a Pipfile but do not include a Pipfile.lock will result in an empty SBOM. Check out the Paketo SBOM documentation for more information about how to access the SBOM.

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> \
  --path <path-to-app> \
  --buildpack <cpython buildpack> \
  --buildpack <pipenv buildpack> \
  --buildpack build/buildpackage.cnb \
  --buildpack <other-buildpacks..>

To run the unit and integration tests for this buildpack:

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