Paketo Buildpack for MRI

gcr.io/paketo-buildpacks/mri

The MRI CNB provides the Matz's Ruby Interpreter (or MRI). The buildpack installs MRI onto the $PATH which makes it available for subsequent buildpacks and in the final running container. It also sets the $GEM_PATH environment variable.

Integration

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

[[requires]]
  # The name of the MRI dependency is "mri". This value is considered
  # part of the public API for the buildpack and will not change without a plan
  # for deprecation.
  name = "mri"
  # The version of the MRI 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 "3.*", "3.2.*", or even
  # "3.2.1".
  version = "3.2.1"
  # The MRI buildpack supports some non-required metadata options.
  [requires.metadata]
    # Setting the build flag to true will ensure that the MRI
    # depdendency is available on the $PATH for subsequent buildpacks during
    # their build phase. If you are writing a buildpack that needs to use MRI
    # during its build process, this flag should be set to true.
    build = true

Usage

To package this buildpack for consumption:

$ ./scripts/package.sh

MRI Configurations

Specifying the MRI version through buildpack.yml configuration will be deprecated in MRI Buildpack v1.0.0.

To migrate from using buildpack.yml please set the $BP_MRI_VERSION environment variable at build time either directly (ex. pack build my-app --env BP_MRI_VERSION=3.2.*) or through a project.toml file

$BP_MRI_VERSION="3.2.1"

This will replace the following structure in buildpack.yml:

mri:
  version: 3.2.1

Logging Configurations

To configure the level of log output from the buildpack itself, set the $BP_LOG_LEVEL environment variable at build time either directly (ex. pack build my-app --env BP_LOG_LEVEL=DEBUG) or through a project.toml file If no value is set, the default value of INFO will be used.

The options for this setting are:

• INFO: (Default) log information about the progress of the build process
• DEBUG: log debugging information about the progress of the build process

$BP_LOG_LEVEL="DEBUG"

Compatibility

This buildpack is currently only supported on the Paketo Bionic and Jammy stack distributions. Pre-compiled distributions of Ruby are provided for the Paketo stacks (i.e. io.buildpacks.stack.jammy and io.buildpacks.stacks.bionic).

Jammy stack support only applies to Ruby version 3.1 and above at this time.

Development

Paketo buildpacks are going through an uniformization of the dev experience across buildpacks, for now just check the scripts/ folder.