sql: Remove dead code

Change I41584c652ab34a267009136ee2a2e159ee2f2a6e ("sql: Squash mitaka
migrations") removed the final users of the 'get_constraints_names',
'add_constraints' and 'remove_constraints' functions.

Change I96cab42cfcfd3e86b53f25abf4cf4043af3b5667 ("sql: Squash ocata
migrations") removed the final use of the 'USE_TRIGGERS' constant.

Change I59882d88fe593ec1ae37415b2157584f7f3c85f8 ("sql: Remove legacy
'migrate_repo' migration repo") removed the final use of
'_assert_not_schema_downgrade' function.

Change-Id: I8aa811ea336e9f613300bc21125e7582010cf5a5
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

keystone/common/sql/upgrades.py

@@ -17,17 +17,12 @@
 import os
 
 import migrate
-from migrate import exceptions
 from migrate.versioning import api as versioning_api
 from oslo_db import exception as db_exception
 from oslo_db.sqlalchemy import migration
-import sqlalchemy
 
 from keystone.common import sql
 from keystone import exception
-from keystone.i18n import _
-
-USE_TRIGGERS = True
 
 INITIAL_VERSION = 72
 EXPAND_REPO = 'expand_repo'
@@ -71,58 +66,6 @@ class Repository(object):
                 session.get_bind(), self.repo_path, self.min_version)
 
 
-#  Different RDBMSs use different schemes for naming the Foreign Key
-#  Constraints.  SQLAlchemy does not yet attempt to determine the name
-#  for the constraint, and instead attempts to deduce it from the column.
-#  This fails on MySQL.
-def get_constraints_names(table, column_name):
-    fkeys = [fk.name for fk in table.constraints
-             if (isinstance(fk, sqlalchemy.ForeignKeyConstraint) and
-                 column_name in fk.columns)]
-    return fkeys
-
-
-#  remove_constraints and add_constraints both accept a list of dictionaries
-#  that contain:
-#  {'table': a sqlalchemy table. The constraint is added to dropped from
-#           this table.
-#  'fk_column': the name of a column on the above table,  The constraint
-#               is added to or dropped from this column
-#  'ref_column':a sqlalchemy column object.  This is the reference column
-#               for the constraint.
-def remove_constraints(constraints):
-    for constraint_def in constraints:
-        constraint_names = get_constraints_names(constraint_def['table'],
-                                                 constraint_def['fk_column'])
-        for constraint_name in constraint_names:
-            migrate.ForeignKeyConstraint(
-                columns=[getattr(constraint_def['table'].c,
-                                 constraint_def['fk_column'])],
-                refcolumns=[constraint_def['ref_column']],
-                name=constraint_name).drop()
-
-
-def add_constraints(constraints):
-    for constraint_def in constraints:
-
-        if constraint_def['table'].kwargs.get('mysql_engine') == 'MyISAM':
-            # Don't try to create constraint when using MyISAM because it's
-            # not supported.
-            continue
-
-        ref_col = constraint_def['ref_column']
-        ref_engine = ref_col.table.kwargs.get('mysql_engine')
-        if ref_engine == 'MyISAM':
-            # Don't try to create constraint when using MyISAM because it's
-            # not supported.
-            continue
-
-        migrate.ForeignKeyConstraint(
-            columns=[getattr(constraint_def['table'].c,
-                             constraint_def['fk_column'])],
-            refcolumns=[constraint_def['ref_column']]).create()
-
-
 def find_repo(repo_name):
     """Return the absolute path to the named repository."""
     path = os.path.abspath(os.path.join(
@@ -146,19 +89,6 @@ def _sync_repo(repo_name):
         )
 
 
-def _assert_not_schema_downgrade(version=None):
-    if version is not None:
-        try:
-            current_ver = int(str(get_db_version()))
-            if int(version) < current_ver:
-                raise migration.exception.DBMigrationError(
-                    _("Unable to downgrade schema"))
-        except exceptions.DatabaseNotControlledError:  # nosec
-            # NOTE(morganfainberg): The database is not controlled, this action
-            # cannot be a downgrade.
-            pass
-
-
 def offline_sync_database_to_version(version=None):
     """Perform and off-line sync of the database.
 
@@ -170,17 +100,7 @@ def offline_sync_database_to_version(version=None):
     version. Downgrading is not supported. If version is specified, then only
     the main database migration is carried out - and the expand, migration and
     contract phases will NOT be run.
-
     """
-    global USE_TRIGGERS
-
-    # This flags let's us bypass trigger setup & teardown for non-rolling
-    # upgrades. We set this as a global variable immediately before handing off
-    # to sqlalchemy-migrate, because we can't pass arguments directly to
-    # migrations that depend on it. We could also register this as a CONF
-    # option, but the idea here is that we aren't exposing a new API.
-    USE_TRIGGERS = False
-
     if version:
         raise Exception('Specifying a version is no longer supported')
 
@@ -241,7 +161,6 @@ def expand_schema():
 
     This is run manually by the keystone-manage command before the first
     keystone node is migrated to the latest release.
-
     """
     validate_upgrade_order(EXPAND_REPO)
     _sync_repo(repo_name=EXPAND_REPO)
@@ -252,7 +171,6 @@ def migrate_data():
 
     This is run manually by the keystone-manage command once the keystone
     schema has been expanded for the new release.
-
     """
     validate_upgrade_order(DATA_MIGRATION_REPO)
     _sync_repo(repo_name=DATA_MIGRATION_REPO)
@@ -264,7 +182,6 @@ def contract_schema():
     This is run manually by the keystone-manage command once the keystone
     nodes have been upgraded to the latest release and will remove any old
     tables/columns that are no longer required.
-
     """
     validate_upgrade_order(CONTRACT_REPO)
     _sync_repo(repo_name=CONTRACT_REPO)