Remove race condition (in FloatingIps)

Soft delete all duplicate rows with the same address except one with
the biggest value in `id` column.

Create UC on columns (address, deleted)

Fix floating_ip_create
  Replace Select then Insert -> Try to Insert.

Fix floating_ip_bulk_create
  Replace get all and locally compare -> Try to Insert

Fix floating_ip_update
  If we update floating_ip with existing address, raise
  rollback and raise FloatingIpExists

Add missing test for floating_ip_update to duplicate

Fixes bug 1145216

blueprint db-enforce-unique-keys

Change-Id: Idd0c8305ca348700235f757a29fc7998edca576b

2 files changed, 57 insertions, 33 deletions

diff --git a/nova/db/sqlalchemy/api.py b/nova/db/sqlalchemy/api.py
index 12ecd0af1..72ade9857 100644
--- a/nova/db/sqlalchemy/api.py
+++ b/nova/db/sqlalchemy/api.py
@@ -685,21 +685,18 @@ def floating_ip_allocate_address(context, project_id, pool):
 
 @require_context
 def floating_ip_bulk_create(context, ips):
-    existing_ips = {}
-    for floating in _floating_ip_get_all(context).all():
-        existing_ips[floating['address']] = floating
-
     session = get_session()
     with session.begin():
         for ip in ips:
-            addr = ip['address']
-            if (addr in existing_ips and
-                ip.get('id') != existing_ips[addr]['id']):
-                raise exception.FloatingIpExists(**dict(existing_ips[addr]))
-
             model = models.FloatingIp()
             model.update(ip)
-            session.add(model)
+            try:
+                # NOTE(boris-42): To get existing address we have to do each
+                #                  time session.flush()..
+                session.add(model)
+                session.flush()
+            except db_exc.DBDuplicateEntry:
+                raise exception.FloatingIpExists(address=ip['address'])
 
 
 def _ip_range_splitter(ips, block_size=256):
@@ -731,25 +728,12 @@ def floating_ip_bulk_destroy(context, ips):
 
 @require_context
 def floating_ip_create(context, values, session=None):
-    if not session:
-        session = get_session()
-
     floating_ip_ref = models.FloatingIp()
     floating_ip_ref.update(values)
-
-    # check uniqueness for not deleted addresses
-    if not floating_ip_ref.deleted:
-        try:
-            floating_ip = _floating_ip_get_by_address(context,
-                                                      floating_ip_ref.address,
-                                                      session)
-        except exception.FloatingIpNotFoundForAddress:
-            pass
-        else:
-            if floating_ip.id != floating_ip_ref.id:
-                raise exception.FloatingIpExists(**dict(floating_ip_ref))
-
-    floating_ip_ref.save(session=session)
+    try:
+        floating_ip_ref.save()
+    except db_exc.DBDuplicateEntry:
+        raise exception.FloatingIpExists(address=values['address'])
     return floating_ip_ref
 
 
@@ -916,12 +900,12 @@ def floating_ip_get_by_fixed_ip_id(context, fixed_ip_id, session=None):
 def floating_ip_update(context, address, values):
     session = get_session()
     with session.begin():
-        floating_ip_ref = _floating_ip_get_by_address(context,
-                                                      address,
-                                                      session)
-        for (key, value) in values.iteritems():
-            floating_ip_ref[key] = value
-        floating_ip_ref.save(session=session)
+        float_ip_ref = _floating_ip_get_by_address(context, address, session)
+        float_ip_ref.update(values)
+        try:
+            float_ip_ref.save(session=session)
+        except db_exc.DBDuplicateEntry:
+            raise exception.FloatingIpExists(address=values['address'])
 
 
 @require_context
diff --git a/nova/db/sqlalchemy/migrate_repo/versions/177_add_floating_ip_uc.py b/nova/db/sqlalchemy/migrate_repo/versions/177_add_floating_ip_uc.py
new file mode 100644
index 000000000..c0dd7c91d
--- /dev/null
+++ b/nova/db/sqlalchemy/migrate_repo/versions/177_add_floating_ip_uc.py
@@ -0,0 +1,40 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright (c) 2013 Boris Pavlovic (boris@pavlovic.me).
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from migrate.changeset import UniqueConstraint
+from sqlalchemy import MetaData, Table
+
+from nova.db.sqlalchemy import utils
+
+
+UC_NAME = "uniq_address_x_deleted"
+COLUMNS = ('address', 'deleted')
+TABLE_NAME = 'floating_ips'
+
+
+def upgrade(migrate_engine):
+    meta = MetaData(bind=migrate_engine)
+    t = Table(TABLE_NAME, meta, autoload=True)
+
+    utils.drop_old_duplicate_entries_from_table(migrate_engine, TABLE_NAME,
+                                                True, *COLUMNS)
+    uc = UniqueConstraint(*COLUMNS, table=t, name=UC_NAME)
+    uc.create()
+
+
+def downgrade(migrate_engine):
+    utils.drop_unique_constraint(migrate_engine, TABLE_NAME, UC_NAME, *COLUMNS)