nova/tools/db/schema_diff.py
Alex Gaynor cd9d8e45c6 Remove the monkey patching of _ into the builtins
Previous _ was monkey patched into builtins whenever
certain modules were imported. This removes that and
simply imports it when it is needed.

Change-Id: I0af2c6d8a230e94440d655d13cab9107ac20d13c
2013-07-26 07:31:17 -07:00

273 lines
7.0 KiB
Python
Executable File

#!/usr/bin/env python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2012 OpenStack Foundation
#
# 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.
"""
Utility for diff'ing two versions of the DB schema.
Each release cycle the plan is to compact all of the migrations from that
release into a single file. This is a manual and, unfortunately, error-prone
process. To ensure that the schema doesn't change, this tool can be used to
diff the compacted DB schema to the original, uncompacted form.
The schema versions are specified by providing a git ref (a branch name or
commit hash) and a SQLAlchemy-Migrate version number:
Run like:
./tools/db/schema_diff.py mysql master:latest my_branch:82
"""
import datetime
import glob
import os
import subprocess
import sys
from nova.openstack.common.gettextutils import _
### Dump
def dump_db(db_driver, db_name, migration_version, dump_filename):
db_driver.create(db_name)
try:
migrate(db_driver, db_name, migration_version)
db_driver.dump(db_name, dump_filename)
finally:
db_driver.drop(db_name)
### Diff
def diff_files(filename1, filename2):
pipeline = ['diff -U 3 %(filename1)s %(filename2)s' % locals()]
# Use colordiff if available
if subprocess.call(['which', 'colordiff']) == 0:
pipeline.append('colordiff')
pipeline.append('less -R')
cmd = ' | '.join(pipeline)
subprocess.check_call(cmd, shell=True)
### Database
class MySQL(object):
def create(self, name):
subprocess.check_call(['mysqladmin', '-u', 'root', 'create', name])
def drop(self, name):
subprocess.check_call(['mysqladmin', '-f', '-u', 'root', 'drop', name])
def dump(self, name, dump_filename):
subprocess.check_call(
'mysqldump -u root %(name)s > %(dump_filename)s' % locals(),
shell=True)
def url(self, name):
return 'mysql://root@localhost/%s' % name
class Postgres(object):
def create(self, name):
subprocess.check_call(['createdb', name])
def drop(self, name):
subprocess.check_call(['dropdb', name])
def dump(self, name, dump_filename):
subprocess.check_call(
'pg_dump %(name)s > %(dump_filename)s' % locals(),
shell=True)
def url(self, name):
return 'postgres://localhost/%s' % name
def _get_db_driver_class(db_type):
if db_type == "mysql":
return MySQL
elif db_type == "postgres":
return Postgres
else:
raise Exception(_("database %s not supported") % db_type)
### Migrate
MIGRATE_REPO = os.path.join(os.getcwd(), "nova/db/sqlalchemy/migrate_repo")
def migrate(db_driver, db_name, migration_version):
earliest_version = _migrate_get_earliest_version()
# NOTE(sirp): sqlalchemy-migrate currently cannot handle the skipping of
# migration numbers.
_migrate_cmd(
db_driver, db_name, 'version_control', str(earliest_version - 1))
upgrade_cmd = ['upgrade']
if migration_version != 'latest':
upgrade_cmd.append(str(migration_version))
_migrate_cmd(db_driver, db_name, *upgrade_cmd)
def _migrate_cmd(db_driver, db_name, *cmd):
manage_py = os.path.join(MIGRATE_REPO, 'manage.py')
args = ['python', manage_py]
args += cmd
args += ['--repository=%s' % MIGRATE_REPO,
'--url=%s' % db_driver.url(db_name)]
subprocess.check_call(args)
def _migrate_get_earliest_version():
versions_glob = os.path.join(MIGRATE_REPO, 'versions', '???_*.py')
versions = []
for path in glob.iglob(versions_glob):
filename = os.path.basename(path)
prefix = filename.split('_', 1)[0]
try:
version = int(prefix)
except ValueError:
pass
versions.append(version)
versions.sort()
return versions[0]
### Git
def git_current_branch_name():
ref_name = git_symbolic_ref('HEAD', quiet=True)
current_branch_name = ref_name.replace('refs/heads/', '')
return current_branch_name
def git_symbolic_ref(ref, quiet=False):
args = ['git', 'symbolic-ref', ref]
if quiet:
args.append('-q')
proc = subprocess.Popen(args, stdout=subprocess.PIPE)
stdout, stderr = proc.communicate()
return stdout.strip()
def git_checkout(branch_name):
subprocess.check_call(['git', 'checkout', branch_name])
def git_has_uncommited_changes():
return subprocess.call(['git', 'diff', '--quiet', '--exit-code']) == 1
### Command
def die(msg):
print >> sys.stderr, "ERROR: %s" % msg
sys.exit(1)
def usage(msg=None):
if msg:
print >> sys.stderr, "ERROR: %s" % msg
prog = "schema_diff.py"
args = ["<mysql|postgres>", "<orig-branch:orig-version>",
"<new-branch:new-version>"]
print >> sys.stderr, "usage: %s %s" % (prog, ' '.join(args))
sys.exit(1)
def parse_options():
try:
db_type = sys.argv[1]
except IndexError:
usage("must specify DB type")
try:
orig_branch, orig_version = sys.argv[2].split(':')
except IndexError:
usage('original branch and version required (e.g. master:82)')
try:
new_branch, new_version = sys.argv[3].split(':')
except IndexError:
usage('new branch and version required (e.g. master:82)')
return db_type, orig_branch, orig_version, new_branch, new_version
def main():
timestamp = datetime.datetime.utcnow().strftime("%Y%m%d_%H%M%S")
ORIG_DB = 'orig_db_%s' % timestamp
NEW_DB = 'new_db_%s' % timestamp
ORIG_DUMP = ORIG_DB + ".dump"
NEW_DUMP = NEW_DB + ".dump"
options = parse_options()
db_type, orig_branch, orig_version, new_branch, new_version = options
# Since we're going to be switching branches, ensure user doesn't have any
# uncommited changes
if git_has_uncommited_changes():
die("You have uncommited changes. Please commit them before running "
"this command.")
db_driver = _get_db_driver_class(db_type)()
users_branch = git_current_branch_name()
git_checkout(orig_branch)
try:
# Dump Original Schema
dump_db(db_driver, ORIG_DB, orig_version, ORIG_DUMP)
# Dump New Schema
git_checkout(new_branch)
dump_db(db_driver, NEW_DB, new_version, NEW_DUMP)
diff_files(ORIG_DUMP, NEW_DUMP)
finally:
git_checkout(users_branch)
if os.path.exists(ORIG_DUMP):
os.unlink(ORIG_DUMP)
if os.path.exists(NEW_DUMP):
os.unlink(NEW_DUMP)
if __name__ == "__main__":
main()