This change improves the responsiveness of the operator when handling
deletion requests by running sync operations in the background and
using context cancellation to interrupt stuck operations.
Changes:
- Add context field to Cluster struct, passed through New()
- Add Cancel() method to cancel cluster's context
- Add StartSync/EndSync/NeedsResync for managing background sync state
- Run Sync() in a background goroutine so worker can process other events
- Add context-aware DB connection methods (initDbConnWithContext)
- Add RetryWithContext() that respects context cancellation
- Cancel cluster context immediately when DeletionTimestamp detected
- Use context-aware connections in syncRoles/syncDatabases
- StartSync/NeedsResync check context cancellation to prevent new syncs
during deletion (no need for separate deleted flag)
Flow:
1. Sync event spawns background goroutine and returns immediately
2. If another sync arrives while one is running, needsResync flag is set
3. When sync completes, it checks needsResync and requeues if needed
4. Delete cancels context -> stuck DB operations return early -> mutex released
5. StartSync/NeedsResync return false when context cancelled
6. Delete proceeds without waiting for slow/stuck sync operations
The flag adds a replica service with the name cluster_name-repl and
a DNS name that defaults to {cluster}-repl.{team}.{hostedzone}.
The implementation converted Service field of the cluster into a map
with one or two elements and deals with the cases when the new flag
is changed on a running cluster
(the update and the sync should create or delete the replica service).
In order to pick up master and replica service and master endpoint
when listing cluster resources.
* Update the spec when updating the cluster.
* move statefulset creation from cluster spec to the separate function
* sync cluster state with desired state;
* move out from arrays for cluster resources;
* recreate pods instead of deleting them in case of statefulset change
* check for master while creating cluster/updating pods
* simplify retryutil
* list pvc while listing resources
* name kubernetes resources with capital letter
* do rolling update in case of env variables change