buildpipe

Buildpipe

A Buildkite plugin to dynamically generate pipelines. Especially useful for monorepos where you want to create dependencies between projects.

Example

initial_pipeline.yml

steps:
  - label: ":buildkite:"
    plugins:
      - jwplayer/buildpipe#v0.8.0:
          dynamic_pipeline: dynamic_pipeline.yml

dynamic_pipeline.yml

projects:
 - label: project1
   path: project1/  # changes in this dir will trigger steps for project1
   skip: deploy*  # skip steps with label matching deploy* (e.g. deploy-prd)
 - label: project2
   skip: test
   path:
      - project2/
      - project1  # you can trigger a project using multiple paths
 - label: project3
   skip:  # you can skip a list of projects
     - test
     - deploy-stg
   path: project3/somedir/  # subpaths can also be triggered
steps:  # the same schema as regular buildkite pipeline steps
  - label: test
    env:
      BUILDPIPE_SCOPE: project  # this variable ensures a test step is generated for each project
    command:
      - cd $$BUILDPIPE_PROJECT_PATH  # BUILDPIPE_PROJECT_PATH will be set by buildpipe
      - make test
  - wait
  - label: build
    branches: "master"
    env:
      BUILDPIPE_SCOPE: project
    command:
      - cd $$BUILDPIPE_PROJECT_PATH
      - make build
      - make publish-image
    agents:
      - queue=build
  - wait
  - label: tag
    branches: "master"
    command:
      - make tag-release
  - wait
  - label: deploy-stg
    branches: "master"
    env:
      BUILDPIPE_SCOPE: project
    command:
      - cd $$BUILDPIPE_PROJECT_PATH
      - make deploy-staging
  - wait
  - block: ":rocket: Release!"
    branches: "master"
  - wait
  - label: deploy-prd
    branches: "master"
    env:
      BUILDPIPE_SCOPE: project
    command:
      - cd $$BUILDPIPE_PROJECT_PATH
      - make deploy-prod

The above pipelines specify the following:

• There are three projects to track in the repository.
• The env variable BUILDPIPE_SCOPE: project tells buildpipe to generate a step for each project if that project changed.
• The skip option will skip any step label matching deploy*.
• The env variable BUILDPIPE_PROJECT_PATH is created by buildpipe as the project's path. If multiple paths are specified for a project, it's the first path.

Full working example

For a full working example, check out Buildkite Monorepo Example.

Configuration

Plugin

Option	Required	Type	Default	Description
default_branch	No	string	master	Default branch of repository
diff_pr	No	string		Override command for non-default branch (see below for a better explanation of the defaults)
diff_default	No	string		Override command for default branch (see below for a better explanation of the defaults)
dynamic_pipeline	Yes	string		The name including the path to the pipeline that contains all the actual steps
log_level	No	string	INFO	The Level of logging to be used by the python script underneath; pass DEBUG for verbose logging if errors occur

Project schema

Option	Required	Type	Default	Description
label	Yes	string		Project label
path	Yes	array		The path(s) that specify changes to a project
skip	No	array		Exclude steps that have labels that match the rule

Other useful things to note:

• Option skip make use of Unix shell-style wildcards (Look at .gitignore files for inspiration)
• If multiple paths are specified, the environment variable BUILDPIPE_PROJECT_PATH will be the first path.

diff_ commands

Depending on your merge strategy, you might need to use different diff command.

Buildpipe assumes you are using a merge strategy on the default branch, which is assumed to be master.

The command for the non-default branch (e.g. when you have a PR up) is:

git log --name-only --no-merges --pretty=format: origin..HEAD

The command for the default branch you merge to is currently:

git log -m -1 --name-only --pretty=format: $BUILDKITE_COMMIT

Requirements

Python3 is currently required, but we are planning to convert buildpipe to a binary using Go.

Just make sure to install Python3 in your agent bootstrap script or Dockerfile.

Cloudformation bootstrap script

# Install python3
yum -y install python3 python3-pip
pip3 install -U setuptools wheel

Agent Dockerfile

FROM buildkite/agent:3.0

RUN apk add --no-cache \
  # Languages
  python3 py-setuptools

Troubleshooting

Buildpipe is incorrectly showing project as changed

Buildkite doesn't by default do clean checkouts. To enable clean checkouts set the BUILDKITE_CLEAN_CHECKOUT environment variable. An example is to modify the pre-checkout hook, .buildkite/hooks/pre-checkout:

#!/bin/bash
set -euo pipefail

echo '--- :house_with_garden: Setting up pre-checkout'

export BUILDKITE_CLEAN_CHECKOUT="true"

Testing

make test

License

MIT

Acknowledgements

The rewrite to a plugin was inspired by git-diff-conditional-buildkite-plugin.