Merge remote-tracking branch 'refs/remotes/drebs/feature/5388_avoid-concurrent-syncs-update-handler-conflict' into develop

2 files changed, 14 insertions, 8 deletions

diff --git a/common/changes/feature_5388_avoid-concurrent-syncs-update-handler-conflict b/common/changes/feature_5388_avoid-concurrent-syncs-update-handler-conflict
new file mode 100644
index 00000000..d0c820db
--- /dev/null
+++ b/common/changes/feature_5388_avoid-concurrent-syncs-update-handler-conflict
@@ -0,0 +1,2 @@
+  o Avoid concurrent syncs problem by adding a lock for PUTting to the sync
+    log update handler (#5388).
diff --git a/common/src/leap/soledad/common/couch.py b/common/src/leap/soledad/common/couch.py
index c0ebc425..ebe8477f 100644
--- a/common/src/leap/soledad/common/couch.py
+++ b/common/src/leap/soledad/common/couch.py
@@ -30,6 +30,7 @@ import threading
 
 
 from StringIO import StringIO
+from collections import defaultdict
 
 
 from couchdb.client import Server
@@ -338,6 +339,8 @@ class CouchDatabase(CommonBackend):
     # We spawn threads to parallelize the CouchDatabase.get_docs() method
     MAX_GET_DOCS_THREADS = 20
 
+    update_handler_lock = defaultdict(threading.Lock)
+
     class _GetDocThread(threading.Thread):
         """
         A thread that gets a document from a database.
@@ -1133,13 +1136,14 @@ class CouchDatabase(CommonBackend):
         ddoc_path = ['_design', 'syncs', '_update', 'put', 'u1db_sync_log']
         res = self._database.resource(*ddoc_path)
         try:
-            res.put_json(
-                body={
-                    'other_replica_uid': other_replica_uid,
-                    'other_generation': other_generation,
-                    'other_transaction_id': other_transaction_id,
-                },
-                headers={'content-type': 'application/json'})
+            with CouchDatabase.update_handler_lock[self._get_replica_uid()]:
+                res.put_json(
+                    body={
+                        'other_replica_uid': other_replica_uid,
+                        'other_generation': other_generation,
+                        'other_transaction_id': other_transaction_id,
+                    },
+                    headers={'content-type': 'application/json'})
         except ResourceNotFound as e:
             raise_missing_design_doc_error(e, ddoc_path)
 
@@ -1367,7 +1371,7 @@ class CouchDatabase(CommonBackend):
             if save_conflict:
                 self._force_doc_sync_conflict(doc)
         if replica_uid is not None and replica_gen is not None:
-            self._do_set_replica_gen_and_trans_id(
+            self._set_replica_gen_and_trans_id(
                 replica_uid, replica_gen, replica_trans_id)
         # update info
         old_doc.rev = doc.rev