gc: increment quay_gc_repos_purged for NamespaceGCWorker (PROJQUAY-1802) (#749)

Since NamespaceGCWorker does a superset of RepositoryGCWorker's
operations, make sure that quay_gc_repos_purged is incremented if
either workers deletes a repository.

data/model/gc.py

@@ -38,7 +38,7 @@ from data.database import (
     DerivedStorageForImage,
 )
 from data.database import TagManifestToManifest, TagToRepositoryTag, TagManifestLabelMap
-from util.metrics.prometheus import gc_table_rows_deleted
+from util.metrics.prometheus import gc_table_rows_deleted, gc_repos_purged
 
 
 logger = logging.getLogger(__name__)
@@ -144,6 +144,7 @@ def purge_repository(repo, force=False):
 
     try:
         fetched.delete_instance(recursive=True, delete_nullable=False, force=force)
+        gc_repos_purged.inc()
         return True
     except IntegrityError:
         return False

util/metrics/prometheus.py

@@ -50,7 +50,8 @@ gc_storage_blobs_deleted = Counter(
 
 # GC iterations
 gc_repos_purged = Counter(
-    "quay_gc_repos_purged", "number of repositories purged by the RepositoryGCWorker"
+    "quay_gc_repos_purged",
+    "number of repositories purged by the RepositoryGCWorker or NamespaceGCWorker",
 )
 gc_namespaces_purged = Counter(
     "quay_gc_namespaces_purged", "number of namespaces purged by the NamespaceGCWorker"

workers/repositorygcworker.py

@@ -8,7 +8,6 @@ from data import model, database
 from workers.queueworker import QueueWorker, WorkerSleepException
 from util.log import logfile_path
 from util.locking import GlobalLock, LockNotAcquiredException
-from util.metrics.prometheus import gc_repos_purged
 from workers.gunicorn_worker import GunicornWorker
 
 logger = logging.getLogger(__name__)
@@ -48,8 +47,6 @@ class RepositoryGCWorker(QueueWorker):
         if not model.gc.purge_repository(marker.repository):
             raise Exception("GC interrupted; will retry")
 
-        gc_repos_purged.inc()
-
 
 def create_gunicorn_worker():
     """