From be6f18892c199c100d5a94f2bb30ddb66c943bb1 Mon Sep 17 00:00:00 2001
From: Victoria Martinez de la Cruz <victoria@redhat.com>
Date: Wed, 30 Mar 2016 15:05:59 -0300
Subject: Fixes migrations for MySQL 5.6.* and MariaDB 10.1.*

In MySQL 5.6/MariaDB 10.1 and later versions there was a change
on the restrictions over foreign keys (FK).

In 019-datastore-fix.py, we attempt to change a column that is part
of a FK from NULL to not NULL. This sort of modifications are not
longer allowed.

This situation caused trove-manage db_sync and trove-manage db_migrate
to fail.

To workaround this, the FK check before executing the ALTER query
is disabled and then reenabled.

Change-Id: I666d01235f2c3225aca3fe7520ebdf6d53831cab
Closes-Bug: #1473226
(cherry picked from commit 679e2283ecc888bd567955b4bf431c87043e8d12)
---
 .../migrate_repo/versions/019_datastore_fix.py     | 23 +++++++++++++++++++---
 trove/db/sqlalchemy/utils.py                       | 15 ++++++++++++++
 2 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/trove/db/sqlalchemy/migrate_repo/versions/019_datastore_fix.py b/trove/db/sqlalchemy/migrate_repo/versions/019_datastore_fix.py
index 1b51ee91..dab329aa 100644
--- a/trove/db/sqlalchemy/migrate_repo/versions/019_datastore_fix.py
+++ b/trove/db/sqlalchemy/migrate_repo/versions/019_datastore_fix.py
@@ -20,6 +20,7 @@ from sqlalchemy.sql.expression import update
 
 from trove.common import cfg
 from trove.db.sqlalchemy.migrate_repo.schema import Table
+from trove.db.sqlalchemy import utils as db_utils
 
 CONF = cfg.CONF
 LEGACY_IMAGE_ID = "00000000-0000-0000-0000-000000000000"
@@ -89,6 +90,9 @@ def upgrade(migrate_engine):
     meta.bind = migrate_engine
 
     instance_table = Table('instances', meta, autoload=True)
+    datastore_versions_table = Table('datastore_versions',
+                                     meta,
+                                     autoload=True)
 
     if has_instances_wo_datastore_version(instance_table):
         instances = find_all_instances_wo_datastore_version(instance_table)
@@ -97,9 +101,6 @@ def upgrade(migrate_engine):
         datastores_table = Table('datastores',
                                  meta,
                                  autoload=True)
-        datastore_versions_table = Table('datastore_versions',
-                                         meta,
-                                         autoload=True)
 
         version_id = create_legacy_version(datastores_table,
                                            datastore_versions_table,
@@ -111,8 +112,24 @@ def upgrade(migrate_engine):
                 values=dict(datastore_version_id=version_id)
             ).execute()
 
+    constraint_names = db_utils.get_foreign_key_constraint_names(
+        engine=migrate_engine,
+        table='instances',
+        columns=['datastore_version_id'],
+        ref_table='datastore_versions',
+        ref_columns=['id'])
+    db_utils.drop_foreign_key_constraints(
+        constraint_names=constraint_names,
+        columns=[instance_table.c.datastore_version_id],
+        ref_columns=[datastore_versions_table.c.id])
+
     instance_table.c.datastore_version_id.alter(nullable=False)
 
+    db_utils.create_foreign_key_constraints(
+        constraint_names=constraint_names,
+        columns=[instance_table.c.datastore_version_id],
+        ref_columns=[datastore_versions_table.c.id])
+
 
 def downgrade(migrate_engine):
     meta.bind = migrate_engine
diff --git a/trove/db/sqlalchemy/utils.py b/trove/db/sqlalchemy/utils.py
index ba5ed2e7..b7079d1d 100644
--- a/trove/db/sqlalchemy/utils.py
+++ b/trove/db/sqlalchemy/utils.py
@@ -52,3 +52,18 @@ def drop_foreign_key_constraints(constraint_names, columns,
                                                refcolumns=ref_columns,
                                                name=constraint_name)
         fkey_constraint.drop()
+
+
+def create_foreign_key_constraints(constraint_names, columns,
+                                   ref_columns):
+    """Create the foreign key constraints that match the given
+    criteria.
+    :param constraint_names: List of foreign key constraint names
+    :param columns: List of the foreign key columns.
+    :param ref_columns: List of the referenced columns.
+    """
+    for constraint_name in constraint_names:
+        fkey_constraint = ForeignKeyConstraint(columns=columns,
+                                               refcolumns=ref_columns,
+                                               name=constraint_name)
+        fkey_constraint.create()
-- 
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