#!/usr/bin/env python # vim: tabstop=4 shiftwidth=4 softtabstop=4 # Copyright 2012 OpenStack LLC. # # 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 ### 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 = ["", "", ""] 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()