March 2024 Summaries

GitHub Actions concurrency controls can prevent overlapping deployments and reduce wasted CI spending by ensuring that only one workflow or job runs for each defined concurrency group while canceling outdated runs when newer commits arrive. A basic configuration using the workflow name as the group and enabling `cancel-in-progress` can stop simultaneous production deployments and obsolete builds, but it may unintentionally cancel tests running for separate pull requests. Including the pull request source branch through `github.head_ref` creates a separate group per PR, allowing each branch’s latest run to continue independently while canceling superseded commits within that PR. The source estimates that effective use of this feature can reduce GitHub Actions costs by around 10%, while promoting Blacksmith as a service for potentially larger savings.