Architecture

Pullup consists of two components: webhook and controller.

Webhook

The webhook listens to GitHub events.

When the webhook receive a event, it will lookup webhooks by the repositories array.

• When a pull request is opened or reopened, the webhook will create a new ResourceSet based on Webhook.
• When a pull request is updated, the webhook will update the existing ResourceSet.
• When a pull request is closed or merged, the webhook will delete ResourceSet matching the labels webhook-name and pull-request-number.

Controller

The controller monitors changes of Webhook and ResourceSet.

Webhook

• When a Webhook is updated, the controller will update spec.resources in ResourceSet matching the label webhook-name.

ResourceSet

• When a ResourceSet is created, the controller will find the original resources by apiVersion, kind and metadata.name.
  • If the resources exist, the controller will merge the resources array into the original resources and create resources using the merged result.
  • If the resources does not exist, the controller will create resources using the resources array directly.
• When a ResourceSet is updated, the controller will also merge the current resource before merging the resources array.

Merge Strategy

• Map
  • Replace existing keys with new values.
  • Copy new keys.
• Array
  • If all elements in the array contain name key, the array will be merged using the name key.
  • Otherwise, replace with new values.

Structured Merge and Diff may be implemented in the future.