cancelot

README

Cancelot

Cancelot (thank you Twitter for the name :D) allows you to cancel previous builds running for the same branch, when you are using VCS triggered builds.

Purpose

Cancelot was built because there is no out of the box solution by CloudBuild, in order to cancel a previous running build upon a new commit in the same branch. This can save a lot of build minutes that would be otherwise billed to the account.

Deploying Cancelot

• Make any changes you need
• Navigate to Cancelot's folder and execute the following: gcloud builds submit . --config=cloudbuild.yaml
• Enjoy

Using Cancelot

Add the builder as the first step in your project's cloudbuild.yaml:

steps:
- name: 'gcr.io/$PROJECT_ID/cancelot'
  args: [ 
    '--current_build_id', '$BUILD_ID',
    '--branch_name', '$BRANCH_NAME'
  ]

Cancelot will be invoked when your build starts and will try to find any running jobs that match the following filter:

build_id != "[CURRENT_BUILD_ID]" AND 
source.repo_source.branch_name = "[BRANCH_NAME]" AND 
status = "WORKING" AND 
start_time<"[CURRENT_BUILD_START_TIME]"

If you'd prefer to only cancel builds that were triggered by the same trigger as your current build, use the --same_trigger_only option:

steps:
- name: 'gcr.io/$PROJECT_ID/cancelot'
  args: [
    '--current_build_id', '$BUILD_ID',
    '--branch_name', '$BRANCH_NAME',
    '--same_trigger_only',
  ]

When using --same_trigger_only, Cancelot will add the following condition to the default filter:

... AND trigger_id = "[CURRENT_BUILD_TRIGGER_ID]"

--same_trigger_only can be helpful if you have multiple repositories connected to the same Cloud Build project or if a single repository has multiple triggers that target the same branch, but with different configurations (e.g., different included / excluded files, tag / branch name patterns, etc).

After successfully fetching the list with the running builds that match the defined criteria, it loops and cancels each one.

Contributing

After making any changes to Cancelot, please navigate to test folder & deploy the cloudbuild.yaml, like this:

gcloud builds submit . --config=cloudbuild.yaml --substitutions=BRANCH_NAME="test"

Inspiration

Cancelot is heavily inspired by slackbot from CloudBuilders community