refactor: Extract definitions of various annotation keys and other defaults to their own source

controllers/constants.go

@@ -0,0 +1,40 @@
+package controllers
+
+import "time"
+
+const (
+	LabelKeyRunnerSetName = "runnerset-name"
+)
+
+const (
+	// This names requires at least one slash to work.
+	// See https://github.com/google/knative-gcp/issues/378
+	runnerPodFinalizerName = "actions.summerwind.dev/runner-pod"
+
+	AnnotationKeyLastRegistrationCheckTime = "actions-runner-controller/last-registration-check-time"
+
+	// AnnotationKeyUnregistrationCompleteTimestamp is the annotation that is added onto the pod once the previously started unregistration process has been completed.
+	AnnotationKeyUnregistrationCompleteTimestamp = "unregistration-complete-timestamp"
+
+	// unregistarionStartTimestamp is the annotation that contains the time that the requested unregistration process has been started
+	AnnotationKeyUnregistrationStartTimestamp = "unregistration-start-timestamp"
+
+	// AnnotationKeyUnregistrationRequestTimestamp is the annotation that contains the time that the unregistration has been requested.
+	// This doesn't immediately start the unregistration. Instead, ARC will first check if the runner has already been registered.
+	// If not, ARC will hold on until the registration to complete first, and only after that it starts the unregistration process.
+	// This is crucial to avoid a race between ARC marking the runner pod for deletion while the actions-runner registers itself to GitHub, leaving the assigned job
+	// hang like forever.
+	AnnotationKeyUnregistrationRequestTimestamp = "unregistration-request-timestamp"
+
+	AnnotationKeyRunnerID = "runner-id"
+
+	// DefaultUnregistrationTimeout is the duration until ARC gives up retrying the combo of ListRunners API (to detect the runner ID by name)
+	// and RemoveRunner API (to actually unregister the runner) calls.
+	// This needs to be longer than 60 seconds because a part of the combo, the ListRunners API, seems to use the Cache-Control header of max-age=60s
+	// and that instructs our cache library httpcache to cache responses for 60 seconds, which results in ARC unable to see the runner in the ListRunners response
+	// up to 60 seconds (or even more depending on the situation).
+	DefaultUnregistrationTimeout = 60 * time.Second
+
+	// This can be any value but a larger value can make an unregistration timeout longer than configured in practice.
+	DefaultUnregistrationRetryDelay = 30 * time.Second
+)