Architecture

Prow in a Nutshell

Prow creates jobs based on various types of events, such as:

• GitHub events (e.g., a new PR is created, or is merged, or a person comments “/retest” on a PR),

• Pub/Sub messages,

• time (these are created by Horologium and are called periodic jobs), and

• retesting (triggered by Tide).

Jobs are created inside the Service Cluster as Kubernetes Custom Resources. The Prow Controller Manager takes triggered jobs and schedules them into a build cluster, where they run as Kubernetes pods. Crier then reports the results back to GitHub.

Notes

Note that Prow can also work with Gerrit, albeit with less features. Specifically, neither Tide nor Hook work with Gerrit yet.