Pip Install Cloud Native Buildpack

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

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

Behavior

This buildpack participates if requirements.txt 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.
  • Prepends the layer site-packages onto PYTHONPATH.
  • If a vendor directory is available, will attempt to run pip install in an offline manner.
• At run time:
  • Does nothing

Integration

The Pip 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 Pip 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 Pip 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 $PYTHONPATH 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 $PYTHONPATH 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 <pip buildpack> -b build/buildpackage.cnb -b <other-buildpacks..>.

To run the unit and integration tests for this buildpack:

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

Configuration

BP_PIP_DEST_PATH

The BP_PIP_DEST_PATH variable allows you to specify a custom vendor directory. This should be a directory underneath the working directory. Will use ./vendor if not provided.

BP_PIP_DEST_PATH=my/custom/vendor-dir

BP_PIP_REQUIREMENT

The BP_PIP_REQUIREMENT variable allows you to specify a custom pip requirement path. This should be a file underneath the working directory. Will use ./requirements.txt if not provided.

BP_PIP_REQUIREMENT=requirements-dev.txt

BP_PIP_FIND_LINKS

The BP_PIP_FIND_LINKS variable allows you to specify one or more directories to pass to --find-links. This should be a local path or file:// URL.

BP_PIP_FIND_LINKS=./vendor-dir

PIP_<UPPER_LONG_NAME>

It is worth noting that the PIP_<UPPER_LONG_NAME> configuration is respected by this buildpack and can be used to tweak the build time CLI properties for Pip as documented in Pip's configuration.