git-diff-conditional-buildkite-plugin

This plugin can be used to create a dynamic pipeline based on your git diff. This requires TWO pipeline files in total and uses docker to run the plugin:

• initial_pipeline - The one that tells buildkite to load the plugin
• dynamic_pipeline - The pipeline which you want to run, but have steps skipped based on conditions held in the initial

But what about mono-repo-diff, it is designed to spin up multiple pipelines based on your git diff. The purpose of this plugin is to spin up a single pipeline based on your git diff. For another similar concept check out the gitlab plugin onlychangesexceptchanges

Getting Started

Please see the below examples on how to use this plugin with buildkite. The buildkite-agent also requires access to docker.

Example

initial_pipeline

steps:
  - label: ":partyparrot: Creating the pipeline"
    plugins:
      - Zegocover/git-diff-conditional#v1.1.1:
          dynamic_pipeline: ".buildkite/dynamic_pipeline.yml"
          steps:
            - label: "build and deploy lambda"
              include:
                - "function_code/*"

dynamic_pipeline

steps:
  - label: "build and deploy lambda"
    commands:
      - make lambda
    agents:
      queue: awesome
    timeout_in_minutes: 10

  - wait

  - label: "terraform apply"
    commands:
      - terraform apply
    agents:
      queue: awesome
    timeout_in_minutes: 10

The above example initial_pipeline will skip the build and deploy lambda step unless there has been a change to the function_code directory. Everything else in the dynamic_pipeline file will be left intact and passed through to buildkite. It is possible to configure numerous label fields, using the configuration options below.

Configuration

Option	Required	Type	Default	Description
dynamic_pipeline	Yes	string		The name including the path to the pipeline that contains all the actual steps
disable_plugin	No	boolean	false	This can be used to pass the entire dynamic_pipeline pipeline straight to buildkite without skipping a single step.
diff	No	string		Can be used to override the default commands (see below for a better explanation of the defaults) Pass a comma-seperated string of git diff commands if you want multiple custom git diff commands run
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
steps	Yes	array		Each Step should contain a label with the include/exclude settings relevant to the label it applies to within the dynamic_pipeline file
label	Yes	string		The label these conditions apply to within the dynamic_pipeline file. (These should be an EXACT match)
include	No	array		If any element is found within the git diff then this step will NOT be skipped
exclude	No	array		If any alement is found within the git diff then this step will be SKIPPED

Other useful things to note:

• Both include and exclude make use of Unix shell-style wildcards (Look at .gitignore files for inspiration)
• Every label defined within the initial_pipeline should contain include, exclude or both

diff command

The default diff commands are (run in the order shown):

# Used to check if on a feature branch and check diff against master
git diff --name-only origin/master...HEAD

# Useful for checking master against master in a merge commit strategy environment
git diff --name-only HEAD HEAD~1

Both of the above commands are run, in their order listed above to detect if there is any diff. If there isn’t any diff then there will be no dynamic_pipeline uploaded. If you wish to disable the plugin temporarily then see the above Configuration

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

We are assuming that you are using a squash and merge strategy on the master branch

Contributing

Please read CONTRIBUTING for details on our code of conduct, and the process for submitting pull requests to us.

Versioning

We use SemVer for versioning. For the versions available, see the tags on this repository.

Authors

• Jack - Initial work - jack1902
• Elliot - Initial work - wizardels

See also the list of contributors who participated in this project.

License

This project is licensed under the MIT License - see the LICENSE file for details

Acknowledgments

• Initially looked at the mono-repo-diff-buildkite-plugin
• Also looked at the gitlab plugin onlychangesexceptchanges