Merge pull request #475 from asadoughi/concurrent_subnet_alloc_pool_cache

Fix subnet_update_set_alloc_pool_cache for concurrent requests

quark/db/api.py

@@ -701,9 +701,13 @@ def subnet_update_set_full(context, subnet):
 def subnet_update_set_alloc_pool_cache(context, subnet, cache_data=None):
     if cache_data is not None:
         cache_data = json.dumps(cache_data)
-    subnet["_allocation_pool_cache"] = cache_data
-    subnet = subnet_update(context, subnet)
-    LOG.debug("Setting alloc pool cache to %s" % cache_data)
+    update_kwargs = {"_allocation_pool_cache": cache_data}
+    query = context.session.query(models.Subnet)
+    query = query.filter(models.Subnet.id == subnet.id)
+    row_count = query.update(update_kwargs,
+                             update_args={"mysql_limit": 1})
+    LOG.debug("Setting alloc pool cache to %s (row_count: %s)" % (
+        cache_data, row_count))
     return subnet
 
 

quark/tests/functional/mysql/test_subnets.py

@@ -0,0 +1,35 @@
+from sqlalchemy.orm import exc
+
+from quark.db import api as db_api
+from quark.tests.functional.mysql.base import MySqlBaseFunctionalTest
+
+
+class TestSubnetsAllocationPoolCache(MySqlBaseFunctionalTest):
+    def setUp(self):
+        super(TestSubnetsAllocationPoolCache, self).setUp()
+
+    def test_subnet_update_set_alloc_pool_cache_concurrency(self):
+        subnet = {"cidr": "192.168.10.0/24"}
+        subnet_db = db_api.subnet_create(self.context, **subnet)
+        self.context.session.flush()
+
+        # establish second session
+        old_session = self.context.session
+        self.context._session = None
+
+        subnet_to_delete = db_api.subnet_find(
+            self.context, id=subnet_db.id, scope=db_api.ONE)
+        db_api.subnet_delete(self.context, subnet_to_delete)
+        self.context.session.flush()
+
+        # restore first session
+        self.context._session = old_session
+
+        try:
+            db_api.subnet_update_set_alloc_pool_cache(
+                self.context, subnet_db, {"foo": "bar"})
+            self.context.session.flush()
+        except exc.StaleDataError as e:
+            self.fail("Did not expect StaleDataError exception: {0}".format(e))
+        self.assertEqual(subnet_db["_allocation_pool_cache"],
+                         "{\"foo\": \"bar\"}")