johnnason / concourse-sandbox

Playpen and examples for https://concourse.ci/

concourse-sandbox

Playpen and examples for concourse CI resources.

Prerequisites:

• concourse installation
• team set up in concourse and target set up using fly.

Git Example: trigger a "changelog" update based off of git commits

git_pipeline_ex.yml is a "toy" changelog builder that triggers off of repo commits. A changelog entry is added to a different repo than the one being monitored. In this example, commits to master on this repo are added to this readme. One could imagine aggregating multiple repo's commits into a single repo's changelog.

The example illustrates a few concourse/git concepts

• using pipeline assets from a git repo
• a pipeline trigger off of repo commits (ci-assets - this repo in this example)
• splitting scripts from tasks
• linking output of one task to input of another
• parameterizing pipleine variables
• pushing commits to a different repo

Assets used

• pipeline git_pipeline_ex.yml
• pipeline credentials credentials_ex.yml
• tasks last-commit.yml update-readme.yml
• scripts last-commit.sh update-readme.sh

The basic pipeline flow

• ci-assets repo commit triggers last-commit
• last-commit pulls and formats the latest commit as output
• update-readme takes the output of last-commit and makes a README.md update in ci-changelog
• pipeline does a put on the ci-changelog repo resource

Running it

• update credentials_ex.yml appropriately
• fly -t <your target> set-pipeline -p git -c ci/git_pipeline_ex.yml -l ci/credentials_ex.yml
• unpause pipeline (UI or via fly)
• commit to master of ci-assets, and you should see a build kick off that culminates in a README.md entry in ci-changelog

To consider

• this is just pattern code, not production ready
• relatively tight coupling between pipeline/tasks/scripts (e.g. file names, etc): needs better parameterization
• even though credentials are externalized, anyone with concourse pipeline access will see them. Consider using an external store, e.g. vault