From 0b5cd9569336727f120641ee724a1c57a6142f53 Mon Sep 17 00:00:00 2001
From: Joseph Schorr <josephschorr@users.noreply.github.com>
Date: Wed, 3 Aug 2016 15:03:02 -0400
Subject: [PATCH] Have repo deletion not lock all the things

---
 data/database.py       | 30 +++++++++++++++++++++++++++++-
 test/test_api_usage.py | 11 +++++++----
 2 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/data/database.py b/data/database.py
index a866aa161..53a53b520 100644
--- a/data/database.py
+++ b/data/database.py
@@ -46,6 +46,32 @@ def real_for_update(query):
 def null_for_update(query):
   return query
 
+def _clear_log_entries(instance, model_class, log_entry_field, *extra_fields):
+  """ Temporary method for clearing out LogEntry records before the general deletion of a
+      dependent record (e.g. Repository or User). Used because deleting all of the log entries
+      under a transaction destroys the database for all other work.
+  """
+  # TODO: Remove this hack once LogEntry no longer has foreign key constraints to everything.
+  # Delete all records in LogEntry that reference the instance.
+  where_clause = (log_entry_field == instance)
+  for field in extra_fields:
+    where_clause = where_clause | (field == instance)
+
+  # Delete the log entries in chunks of 1000.
+  deleted_count = 1
+  while deleted_count >= 1:
+    todelete = (LogEntry
+                .select(LogEntry.id)
+                .where(where_clause)
+                .limit(1000)
+                .alias('todelete'))
+
+    subquery = (LogEntry
+                .select(todelete.c.id)
+                .from_(todelete))
+
+    deleted_count = LogEntry.delete().where(LogEntry.id << subquery).execute()
+
 def delete_instance_filtered(instance, model_class, delete_nullable, skip_transitive_deletes):
   """ Deletes the DB instance recursively, skipping any models in the skip_transitive_deletes set.
 
@@ -88,6 +114,7 @@ def delete_instance_filtered(instance, model_class, delete_nullable, skip_transi
   with db_transaction():
     for query, fk in filtered_ops:
       model = fk.model_class
+
       if fk.null and not delete_nullable:
         model.update(**{fk.name: None}).where(query).execute()
       else:
@@ -320,6 +347,7 @@ class User(BaseModel):
       # These models don't need to use transitive deletes, because the referenced objects
       # are cleaned up directly
       skip_transitive_deletes = {Image}
+      _clear_log_entries(self, User, LogEntry.performer, LogEntry.account)
       delete_instance_filtered(self, User, delete_nullable, skip_transitive_deletes)
 
 
@@ -416,7 +444,7 @@ class Repository(BaseModel):
     # are cleaned up directly
     skip_transitive_deletes = {RepositoryTag, RepositoryBuild, RepositoryBuildTrigger, BlobUpload,
                                Image, TagManifest, DerivedStorageForImage}
-
+    _clear_log_entries(self, User, LogEntry.repository)
     delete_instance_filtered(self, Repository, delete_nullable, skip_transitive_deletes)
 
 
diff --git a/test/test_api_usage.py b/test/test_api_usage.py
index d0cf90589..842f07e5b 100644
--- a/test/test_api_usage.py
+++ b/test/test_api_usage.py
@@ -1654,14 +1654,17 @@ class log_queries(object):
 
 
 class check_transitive_deletes(log_queries):
-  def __init__(self):
+  def __init__(self, allowed_query_check=None):
     super(check_transitive_deletes, self).__init__(query_filter=r'^DELETE.+IN \(SELECT.+$')
+    self.allowed_query_check = allowed_query_check
 
   def __exit__(self, exc_type, exc_val, exc_tb):
     super(check_transitive_deletes, self).__exit__(exc_type, exc_val, exc_tb)
     queries = self.get_queries()
-    if queries:
-      raise Exception('Detected transitive deletion in queries: %s' % queries)
+    if queries and self.allowed_query_check:
+      for query in queries:
+        if query.find(self.allowed_query_check) < 0:
+          raise Exception('Detected transitive deletion in queries: %s' % queries)
 
 
 class TestDeleteRepository(ApiTestCase):
@@ -1747,7 +1750,7 @@ class TestDeleteRepository(ApiTestCase):
                                  date=datetime.datetime.now() - datetime.timedelta(days=5), count=6)
 
     # Delete the repository.
-    with check_transitive_deletes():
+    with check_transitive_deletes(allowed_query_check='todelete'):
       self.deleteResponse(Repository, params=dict(repository=self.COMPLEX_REPO))
 
     # Verify the repo was deleted.