Restore the check_foreign_keys() method.1.4.1

This method was prematurely removed from oslo.db without
a deprecation phase, when Alembic added support for
foreign key autodetection.   oslo.db continues to use
alembic for this purpose, however the
ModelsMigrationsSync.check_foreign_keys() method is restored
directly for those projects which were calling into it
explicitly.

Change-Id: Id892567bd60d6b4b88765bbfe3cd5c5e75910b25

2 files changed, 259 insertions, 0 deletions

diff --git a/oslo_db/sqlalchemy/test_migrations.py b/oslo_db/sqlalchemy/test_migrations.py
index 8990790..9b65421 100644
--- a/oslo_db/sqlalchemy/test_migrations.py
+++ b/oslo_db/sqlalchemy/test_migrations.py
@@ -15,6 +15,7 @@
 #    under the License.
 
 import abc
+import collections
 import logging
 import pprint
 
@@ -510,6 +511,77 @@ class ModelsMigrationsSync(object):
             for table in tbs:
                 conn.execute(schema.DropTable(table))
 
+    FKInfo = collections.namedtuple('fk_info', ['constrained_columns',
+                                                'referred_table',
+                                                'referred_columns'])
+
+    def check_foreign_keys(self, metadata, bind):
+        """Compare foreign keys between model and db table.
+
+        :returns: a list that contains information about:
+
+         * should be a new key added or removed existing,
+         * name of that key,
+         * source table,
+         * referred table,
+         * constrained columns,
+         * referred columns
+
+         Output::
+
+             [('drop_key',
+               'testtbl_fk_check_fkey',
+               'testtbl',
+               fk_info(constrained_columns=(u'fk_check',),
+                       referred_table=u'table',
+                       referred_columns=(u'fk_check',)))]
+
+        DEPRECATED: this function is deprecated and will be removed from
+        oslo.db in a few releases. Alembic autogenerate.compare_metadata()
+        now includes foreign key comparison directly.
+
+        """
+
+        diff = []
+        insp = sqlalchemy.engine.reflection.Inspector.from_engine(bind)
+        # Get all tables from db
+        db_tables = insp.get_table_names()
+        # Get all tables from models
+        model_tables = metadata.tables
+        for table in db_tables:
+            if table not in model_tables:
+                continue
+            # Get all necessary information about key of current table from db
+            fk_db = dict((self._get_fk_info_from_db(i), i['name'])
+                         for i in insp.get_foreign_keys(table))
+            fk_db_set = set(fk_db.keys())
+            # Get all necessary information about key of current table from
+            # models
+            fk_models = dict((self._get_fk_info_from_model(fk), fk)
+                             for fk in model_tables[table].foreign_keys)
+            fk_models_set = set(fk_models.keys())
+            for key in (fk_db_set - fk_models_set):
+                diff.append(('drop_key', fk_db[key], table, key))
+                LOG.info(("Detected removed foreign key %(fk)r on "
+                          "table %(table)r"), {'fk': fk_db[key],
+                                               'table': table})
+            for key in (fk_models_set - fk_db_set):
+                diff.append(('add_key', fk_models[key], table, key))
+                LOG.info((
+                    "Detected added foreign key for column %(fk)r on table "
+                    "%(table)r"), {'fk': fk_models[key].column.name,
+                                   'table': table})
+        return diff
+
+    def _get_fk_info_from_db(self, fk):
+        return self.FKInfo(tuple(fk['constrained_columns']),
+                           fk['referred_table'],
+                           tuple(fk['referred_columns']))
+
+    def _get_fk_info_from_model(self, fk):
+        return self.FKInfo((fk.parent.name,), fk.column.table.name,
+                           (fk.column.name,))
+
     def test_models_sync(self):
         # recent versions of sqlalchemy and alembic are needed for running of
         # this test, but we already have them in requirements
diff --git a/oslo_db/tests/sqlalchemy/test_migrations.py b/oslo_db/tests/sqlalchemy/test_migrations.py
index ad71757..1bae701 100644
--- a/oslo_db/tests/sqlalchemy/test_migrations.py
+++ b/oslo_db/tests/sqlalchemy/test_migrations.py
@@ -307,3 +307,190 @@ class ModelsMigrationsSyncPsql(ModelsMigrationSyncMixin,
 
     def test_models_not_sync(self):
         self._test_models_not_sync()
+
+
+class TestOldCheckForeignKeys(test_base.DbTestCase):
+    def setUp(self):
+        super(TestOldCheckForeignKeys, self).setUp()
+
+        test = self
+
+        class MigrateSync(migrate.ModelsMigrationsSync):
+            def get_engine(self):
+                return test.engine
+
+            def get_metadata(self):
+                return test.metadata
+
+            def db_sync(self):
+                raise NotImplementedError()
+
+        self.migration_sync = MigrateSync()
+
+    def _fk_added_fixture(self):
+        self.metadata = sa.MetaData()
+        self.metadata_migrations = sa.MetaData()
+
+        sa.Table(
+            'testtbl_one', self.metadata,
+            sa.Column('id', sa.Integer, primary_key=True),
+            mysql_engine='InnoDB'
+        )
+
+        sa.Table(
+            'testtbl_two', self.metadata,
+            sa.Column('id', sa.Integer, primary_key=True),
+            sa.Column('tone_id', sa.Integer),
+            mysql_engine='InnoDB'
+        )
+
+        sa.Table(
+            'testtbl_one', self.metadata_migrations,
+            sa.Column('id', sa.Integer, primary_key=True),
+            mysql_engine='InnoDB'
+        )
+
+        sa.Table(
+            'testtbl_two', self.metadata_migrations,
+            sa.Column('id', sa.Integer, primary_key=True),
+            sa.Column(
+                'tone_id', sa.Integer,
+                sa.ForeignKey('testtbl_one.id', name="tone_id_fk")),
+            mysql_engine='InnoDB'
+        )
+
+    def _fk_removed_fixture(self):
+        self.metadata = sa.MetaData()
+        self.metadata_migrations = sa.MetaData()
+
+        sa.Table(
+            'testtbl_one', self.metadata,
+            sa.Column('id', sa.Integer, primary_key=True),
+            mysql_engine='InnoDB'
+        )
+
+        sa.Table(
+            'testtbl_two', self.metadata,
+            sa.Column('id', sa.Integer, primary_key=True),
+            sa.Column(
+                'tone_id', sa.Integer,
+                sa.ForeignKey('testtbl_one.id', name="tone_id_fk")),
+            mysql_engine='InnoDB'
+        )
+
+        sa.Table(
+            'testtbl_one', self.metadata_migrations,
+            sa.Column('id', sa.Integer, primary_key=True),
+            mysql_engine='InnoDB'
+        )
+
+        sa.Table(
+            'testtbl_two', self.metadata_migrations,
+            sa.Column('id', sa.Integer, primary_key=True),
+            sa.Column('tone_id', sa.Integer),
+            mysql_engine='InnoDB'
+        )
+
+    def _fk_no_change_fixture(self):
+        self.metadata = sa.MetaData()
+        self.metadata_migrations = sa.MetaData()
+
+        sa.Table(
+            'testtbl_one', self.metadata,
+            sa.Column('id', sa.Integer, primary_key=True),
+            mysql_engine='InnoDB'
+        )
+
+        sa.Table(
+            'testtbl_two', self.metadata,
+            sa.Column('id', sa.Integer, primary_key=True),
+            sa.Column(
+                'tone_id', sa.Integer,
+                sa.ForeignKey('testtbl_one.id', name="tone_id_fk")),
+            mysql_engine='InnoDB'
+        )
+
+        sa.Table(
+            'testtbl_one', self.metadata_migrations,
+            sa.Column('id', sa.Integer, primary_key=True),
+            mysql_engine='InnoDB'
+        )
+
+        sa.Table(
+            'testtbl_two', self.metadata_migrations,
+            sa.Column('id', sa.Integer, primary_key=True),
+            sa.Column(
+                'tone_id', sa.Integer,
+                sa.ForeignKey('testtbl_one.id', name="tone_id_fk")),
+            mysql_engine='InnoDB'
+        )
+
+    def _run_test(self):
+        self.metadata.create_all(bind=self.engine)
+        return self.migration_sync.check_foreign_keys(
+            self.metadata_migrations, self.engine)
+
+    def _compare_diffs(self, diffs, compare_to):
+        diffs = [
+            (
+                cmd,
+                fk._get_colspec() if isinstance(fk, sa.ForeignKey)
+                else "tone_id_fk" if fk is None  # sqlite workaround
+                else fk,
+                tname, fk_info
+            )
+            for cmd, fk, tname, fk_info in diffs
+        ]
+        self.assertEqual(diffs, compare_to)
+
+    def test_fk_added(self):
+        self._fk_added_fixture()
+        diffs = self._run_test()
+
+        self._compare_diffs(
+            diffs,
+            [(
+                'add_key',
+                'testtbl_one.id',
+                'testtbl_two',
+                self.migration_sync.FKInfo(
+                    constrained_columns=('tone_id',),
+                    referred_table='testtbl_one',
+                    referred_columns=('id',))
+            )]
+        )
+
+    def test_fk_removed(self):
+        self._fk_removed_fixture()
+        diffs = self._run_test()
+
+        self._compare_diffs(
+            diffs,
+            [(
+                'drop_key',
+                "tone_id_fk",
+                'testtbl_two',
+                self.migration_sync.FKInfo(
+                    constrained_columns=('tone_id',),
+                    referred_table='testtbl_one',
+                    referred_columns=('id',))
+            )]
+        )
+
+    def test_fk_no_change(self):
+        self._fk_no_change_fixture()
+        diffs = self._run_test()
+
+        self._compare_diffs(
+            diffs,
+            [])
+
+
+class PGTestOldCheckForeignKeys(
+        TestOldCheckForeignKeys, test_base.PostgreSQLOpportunisticTestCase):
+    pass
+
+
+class MySQLTestOldCheckForeignKeys(
+        TestOldCheckForeignKeys, test_base.MySQLOpportunisticTestCase):
+    pass