This adds the initial version of ScheduledOverrides to HorizontalRunnerAutoscaler.
`MinReplicas` overriding should just work.
When there are two or more ScheduledOverrides, the earliest one that matched is activated. Each ScheduledOverride can be recurring or one-time. If you have two or more ScheduledOverrides, only one of them should be one-time. And the one-time override should be the earliest item in the list to make sense.
Tests will be added in another commit. Logging improvements and additional observability in HRA.Status will also be added in yet another commits.
Ref #484
As part of #282, I have introduced some caching mechanism to avoid excessive GitHub API calls due to the autoscaling calculation involving GitHub API calls is executed on each Webhook event.
Apparently, it was saving the wrong value in the cache- The value was one after applying `HRA.Spec.{Max,Min}Replicas` so manual changes to {Max,Min}Replicas doesn't affect RunnerDeployment.Spec.Replicas until the cache expires. This isn't what I had wanted.
This patch fixes that, by changing the value being cached to one before applying {Min,Max}Replicas.
Additionally, I've also updated logging so that you observe which number was fetched from cache, and what number was suggested by either TotalNumberOfQueuedAndInProgressWorkflowRuns or PercentageRunnersBusy, and what was the final number used as the desired-replicas(after applying {Min,Max}Replicas).
Follow-up for #282
We sometimes see that integration test fails due to runner replicas not meeting the expected number in a timely manner. After investigating a bit, this turned out to be due to that HRA updates on webhook-based autoscaler and HRA controller are conflicting. This changes the controllers to use Patch instead of Update to make conflicts less likely to happen.
I have also updated the hra controller to use Patch when updating RunnerDeployment, too.
Overall, these changes should make the webhook-based autoscaling more reliable due to less conflicts.
`kubectl get horizontalrunnerautoscalers.actions.summerwind.dev` shows HRA.status.desiredReplicas as the DESIRED count. However the value had been not taking capacityReservations into account, which resulted in showing incorrect count when you used webhook-based autoscaler, or capacityReservations API directly. This fixes that.
* feat: HorizontalRunnerAutoscaler Webhook server
This introduces a Webhook server that responds GitHub `check_run`, `pull_request`, and `push` events by scaling up matched HorizontalRunnerAutoscaler by 1 replica. This allows you to immediately add "resource slack" for future GitHub Actions job runs, without waiting next sync period to add insufficient runners.
This feature is highly inspired by https://github.com/philips-labs/terraform-aws-github-runner. terraform-aws-github-runner can manage one set of runners per deployment, where actions-runner-controller with this feature can manage as many sets of runners as you declare with HorizontalRunnerAutoscaler and RunnerDeployment pairs.
On each GitHub event received, the webhook server queries repository-wide and organizational runners from the cluster and searches for the single target to scale up. The webhook server tries to match HorizontalRunnerAutoscaler.Spec.ScaleUpTriggers[].GitHubEvent.[CheckRun|Push|PullRequest] against the event and if it finds only one HRA, it is the scale target. If none or two or more targets are found for repository-wide runners, it does the same on organizational runners.
Changes:
* Fix integration test
* Update manifests
* chart: Add support for github webhook server
* dockerfile: Include github-webhook-server binary
* Do not import unversioned go-github
* Update README
This is a follow-up for #66.
The reconciler for the new HorizontalRunnerDeploymentAutoscaler had a terrible flaw that prevented the controller to fail launching due to an error like:
```
indexer conflict: map[field:.metadata.controller:{}]
```
This fixes that, while adding `integration_test.go` to verify its actually fixed and prevent regression in the future.
Yusuke Kuoka
Christoph Brand
Hidetake Iwata
Yusuke Kuoka