Description: Make ceilometer work with sqla 0.9.x
 Ceilometer's migration 028 makes some very specific assumptions about sqla
 data structures and exception paths, which are not true in sqla 0.9.x. In 0.8
 you were shielded from errors on drop by sqla, but in 0.9 you get raw
 exceptions from the db layer thrown all the way up, which causes a failure
 condition when trying to delete the non existent alembic table.
 .
 We can get basically the same behavior as before by using the checkfirst=True
 parameter on table definitions. This will actually ensure that we get the
 table in question, and get the NoSuchTableError when we expect it.
Author: Sean Dague <sean.dague@samsung.com>
Date: Mon, 10 Mar 2014 22:06:32 +0000 (-0400)
X-Git-Url: https://review.openstack.org/gitweb?p=openstack%2Fceilometer.git;a=commitdiff_plain;h=63f6d6af77d5fe7227b074ddc3e1594a424873e6
Origin: upstream, https://review.openstack.org/#/c/79482/
Change-Id: Ida33a3030fb03c2f3eeed9f129fcc0063a7b7c4b

diff --git a/ceilometer/storage/sqlalchemy/migrate_repo/versions/028_alembic_migrations.py b/ceilometer/storage/sqlalchemy/migrate_repo/versions/028_alembic_migrations.py
index b527692..567620c 100644
--- a/ceilometer/storage/sqlalchemy/migrate_repo/versions/028_alembic_migrations.py
+++ b/ceilometer/storage/sqlalchemy/migrate_repo/versions/028_alembic_migrations.py
@@ -21,7 +21,10 @@ import sqlalchemy as sa
 def get_alembic_version(meta):
     """Return Alembic version or None if no Alembic table exists."""
     try:
-        a_ver = sa.Table('alembic_version', meta, autoload=True)
+        a_ver = sa.Table(
+            'alembic_version',
+            meta,
+            autoload=True)
         return sa.select([a_ver.c.version_num]).scalar()
     except sa.exc.NoSuchTableError:
         return None
@@ -29,7 +32,10 @@ def get_alembic_version(meta):
 
 def delete_alembic(meta):
     try:
-        sa.Table('alembic_version', meta, autoload=True).drop()
+        sa.Table(
+            'alembic_version',
+            meta,
+            autoload=True).drop(checkfirst=True)
     except sa.exc.NoSuchTableError:
         pass