themodernlife / pipenv-install

Pipenv Install Cloud Native Buildpack

The Paketo Pipenv Install Buildpack 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 the app.

The buildpack will do the following:

• At build time:
  • Installs the application packages to a layer made available to the app.
  • Sets the PYTHONUSERBASE to this layer.
  • Prepends the layer's bin directory to the PATH.
• At run time:
  • Does nothing

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 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]

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

    # Setting the launch flag to true will ensure that the site-packages
    # dependency is available on the $PYTHONUSERBASE/$PATH for the running
    # application. If you are writing an application that needs site-packages
    # 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 <cpython buildpack> -b <pipenv buildpack> -b build/buildpackage.cnb -b <other-buildpacks..>.

To run the unit and integration tests for this buildpack:

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