Have the BlobUpload cleanup worker run on a single instance only (#239)

Instead of running simultaneously across multiple nodes, we change the
worker to run only from a single instance. This is better for the DB and
the previous behavior was not necessary given the size of the BlobUpload
table.

Fixes https://issues.redhat.com/browse/PROJQUAY-365

data/model/blob.py

@@ -169,31 +169,18 @@ def _temp_link_blob(repository_id, storage, link_expiration_s):
 
 def get_stale_blob_upload(stale_timespan):
     """
-    Returns a random blob upload which was created before the stale timespan.
+    Returns a blob upload which was created before the stale timespan.
     """
     stale_threshold = datetime.now() - stale_timespan
 
     try:
         candidates = (
-            BlobUpload.select()
-            .where(BlobUpload.created <= stale_threshold)
-            .limit(500)
-            .distinct()
-            .alias("candidates")
-        )
-
-        found = (
-            BlobUpload.select(candidates.c.id).from_(candidates).order_by(db_random_func()).get()
-        )
-        if not found:
-            return None
-
-        return (
             BlobUpload.select(BlobUpload, ImageStorageLocation)
             .join(ImageStorageLocation)
-            .where(BlobUpload.id == found.id)
-            .get()
+            .where(BlobUpload.created <= stale_threshold)
         )
+
+        return candidates.get()
     except BlobUpload.DoesNotExist:
         return None
 

workers/blobuploadcleanupworker/blobuploadcleanupworker.py

@@ -1,29 +1,45 @@
 import logging
 import logging.config
 
-from datetime import timedelta
+from datetime import timedelta, datetime
 
 from app import app, storage
 from data.database import UseThenDisconnect
 from workers.blobuploadcleanupworker.models_pre_oci import pre_oci_model as model
 from workers.worker import Worker
 from util.log import logfile_path
+from util.locking import GlobalLock, LockNotAcquiredException
+
 
 logger = logging.getLogger(__name__)
 
 DELETION_DATE_THRESHOLD = timedelta(days=2)
 BLOBUPLOAD_CLEANUP_FREQUENCY = app.config.get("BLOBUPLOAD_CLEANUP_FREQUENCY", 60 * 60)
+LOCK_TTL = 60 * 20  # 20 minutes
 
 
 class BlobUploadCleanupWorker(Worker):
     def __init__(self):
         super(BlobUploadCleanupWorker, self).__init__()
-        self.add_operation(self._cleanup_uploads, BLOBUPLOAD_CLEANUP_FREQUENCY)
+        self.add_operation(self._try_cleanup_uploads, BLOBUPLOAD_CLEANUP_FREQUENCY)
 
-    def _cleanup_uploads(self):
+    def _try_cleanup_uploads(self):
         """
         Performs garbage collection on the blobupload table.
         """
+        try:
+            with GlobalLock("BLOB_CLEANUP", lock_ttl=LOCK_TTL):
+                self._cleanup_uploads()
+        except LockNotAcquiredException:
+            logger.debug("Could not acquire global lock for blob upload cleanup worker")
+            return
+
+    def _cleanup_uploads(self):
+        """
+        Performs cleanup on the blobupload table.
+        """
+        logger.debug("Performing blob upload cleanup")
+
         while True:
             # Find all blob uploads older than the threshold (typically a week) and delete them.
             with UseThenDisconnect(app.config):
@@ -34,6 +50,8 @@ class BlobUploadCleanupWorker(Worker):
 
             # Remove the stale upload from storage.
             logger.debug("Removing stale blob upload %s", stale_upload.uuid)
+            assert stale_upload.created <= (datetime.utcnow() - DELETION_DATE_THRESHOLD)
+
             try:
                 storage.cancel_chunked_upload(
                     [stale_upload.location_name], stale_upload.uuid, stale_upload.storage_metadata

workers/blobuploadcleanupworker/models_interface.py

@@ -3,7 +3,9 @@ from collections import namedtuple
 from six import add_metaclass
 
 
-class BlobUpload(namedtuple("BlobUpload", ["uuid", "storage_metadata", "location_name"])):
+class BlobUpload(
+    namedtuple("BlobUpload", ["uuid", "storage_metadata", "location_name", "created"])
+):
     """
     BlobUpload represents a single upload of a blob in progress or previously started.
     """

workers/blobuploadcleanupworker/models_pre_oci.py

@@ -14,7 +14,12 @@ class PreOCIModel(BlobUploadCleanupWorkerDataInterface):
         if blob_upload is None:
             return None
 
-        return BlobUpload(blob_upload.uuid, blob_upload.storage_metadata, blob_upload.location.name)
+        return BlobUpload(
+            blob_upload.uuid,
+            blob_upload.storage_metadata,
+            blob_upload.location.name,
+            blob_upload.created,
+        )
 
     def delete_blob_upload(self, blob_upload):
         blob_upload = model.blob.get_blob_upload_by_uuid(blob_upload.uuid)
@@ -30,7 +35,12 @@ class PreOCIModel(BlobUploadCleanupWorkerDataInterface):
         blob_upload = model.blob.initiate_upload("devtable", "simple", "foobarbaz", "local_us", {})
         blob_upload.created = datetime.now() - timedelta(days=60)
         blob_upload.save()
-        return BlobUpload(blob_upload.uuid, blob_upload.storage_metadata, blob_upload.location.name)
+        return BlobUpload(
+            blob_upload.uuid,
+            blob_upload.storage_metadata,
+            blob_upload.location.name,
+            blob_upload.created,
+        )
 
     def blob_upload_exists(self, upload_uuid):
         blob_upload = model.blob.get_blob_upload_by_uuid(upload_uuid)