Have the RepositoryActionCount worker cleanup old rows in RAC (#274)

We don't make use of any action counts older than a year, so this
change will have the worker remove old rows, one month (roughly) at
a time

data/model/repositoryactioncount.py

@@ -31,6 +31,8 @@ SEARCH_BUCKETS = [
     search_bucket(timedelta(days=183), 152, 0.71028),
 ]
 
+RAC_RETENTION_PERIOD = timedelta(days=365)
+
 
 def find_uncounted_repository():
     """
@@ -157,3 +159,28 @@ def update_repository_score(repo):
     except IntegrityError:
         logger.debug("RepositorySearchScore row already existed; skipping")
         return False
+
+
+def delete_expired_entries(repo, limit=100):
+    """ Deletes expired entries from the RepositoryActionCount table for a specific repository.
+        Returns the number of entries removed.
+    """
+    threshold_date = datetime.today() - RAC_RETENTION_PERIOD
+    found = list(
+        RepositoryActionCount.select().where(
+            RepositoryActionCount.repository == repo, RepositoryActionCount.date < threshold_date
+        )
+    )
+
+    if not found:
+        return 0
+
+    count_removed = 0
+    for entry in found:
+        try:
+            entry.delete_instance(recursive=False)
+            count_removed += 1
+        except IntegrityError:
+            continue
+
+    return count_removed

workers/repositoryactioncounter.py

@@ -24,19 +24,22 @@ class RepositoryActionCountWorker(Worker):
         """
         Counts actions and aggregates search scores for a random repository for the previous day.
         """
+        # Select a repository that needs its actions for the last day updated.
         to_count = model.repositoryactioncount.find_uncounted_repository()
         if to_count is None:
             logger.debug("No further repositories to count")
             return False
 
-        yesterday = date.today() - timedelta(days=1)
-
         logger.debug("Found repository #%s to count", to_count.id)
+
+        # Count the number of actions that occurred yesterday for the repository.
+        yesterday = date.today() - timedelta(days=1)
         daily_count = logs_model.count_repository_actions(to_count, yesterday)
         if daily_count is None:
             logger.debug("Could not load count for repository #%s", to_count.id)
             return False
 
+        # Store the count for the repository.
         was_counted = model.repositoryactioncount.store_repository_action_count(
             to_count, yesterday, daily_count
         )
@@ -44,6 +47,7 @@ class RepositoryActionCountWorker(Worker):
             logger.debug("Repository #%s was counted by another worker", to_count.id)
             return False
 
+        # Update the search score for the repository now that its actions have been counted.
         logger.debug("Updating search score for repository #%s", to_count.id)
         was_updated = model.repositoryactioncount.update_repository_score(to_count)
         if not was_updated:
@@ -53,6 +57,14 @@ class RepositoryActionCountWorker(Worker):
             return False
 
         logger.debug("Repository #%s search score updated", to_count.id)
+
+        # Delete any entries older than the retention period for the repository.
+        while True:
+            found = model.repositoryactioncount.delete_expired_entries(to_count, 30)
+            if found <= 0:
+                break
+
+        logger.debug("Repository #%s old entries removed", to_count.id)
         return True