Run _upgrade_existing_database on workers if at current schema_version (#11346)

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>
This commit is contained in:
Andrew Morgan 2021-11-15 17:34:15 +00:00 committed by GitHub
parent b596a1eb80
commit 9c59e117db
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3 changed files with 74 additions and 19 deletions

1
changelog.d/11346.bugfix Normal file
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@ -0,0 +1 @@
Fix a bug introduced in v1.47.0rc1 which caused worker processes to not halt startup in the presence of outstanding database migrations.

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@ -131,24 +131,16 @@ def prepare_database(
"config==None in prepare_database, but database is not empty"
)
# if it's a worker app, refuse to upgrade the database, to avoid multiple
# workers doing it at once.
if config.worker.worker_app is None:
_upgrade_existing_database(
cur,
version_info,
database_engine,
config,
databases=databases,
)
elif version_info.current_version < SCHEMA_VERSION:
# If the DB is on an older version than we expect then we refuse
# to start the worker (as the main process needs to run first to
# update the schema).
raise UpgradeDatabaseException(
OUTDATED_SCHEMA_ON_WORKER_ERROR
% (SCHEMA_VERSION, version_info.current_version)
)
# This should be run on all processes, master or worker. The master will
# apply the deltas, while workers will check if any outstanding deltas
# exist and raise an PrepareDatabaseException if they do.
_upgrade_existing_database(
cur,
version_info,
database_engine,
config,
databases=databases,
)
else:
logger.info("%r: Initialising new database", databases)
@ -358,6 +350,18 @@ def _upgrade_existing_database(
is_worker = config and config.worker.worker_app is not None
# If the schema version needs to be updated, and we are on a worker, we immediately
# know to bail out as workers cannot update the database schema. Only one process
# must update the database at the time, therefore we delegate this task to the master.
if is_worker and current_schema_state.current_version < SCHEMA_VERSION:
# If the DB is on an older version than we expect then we refuse
# to start the worker (as the main process needs to run first to
# update the schema).
raise UpgradeDatabaseException(
OUTDATED_SCHEMA_ON_WORKER_ERROR
% (SCHEMA_VERSION, current_schema_state.current_version)
)
if (
current_schema_state.compat_version is not None
and current_schema_state.compat_version > SCHEMA_VERSION

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@ -11,6 +11,9 @@
# 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.
from typing import List
from unittest import mock
from synapse.app.generic_worker import GenericWorkerServer
from synapse.storage.database import LoggingDatabaseConnection
from synapse.storage.prepare_database import PrepareDatabaseException, prepare_database
@ -19,6 +22,22 @@ from synapse.storage.schema import SCHEMA_VERSION
from tests.unittest import HomeserverTestCase
def fake_listdir(filepath: str) -> List[str]:
"""
A fake implementation of os.listdir which we can use to mock out the filesystem.
Args:
filepath: The directory to list files for.
Returns:
A list of files and folders in the directory.
"""
if filepath.endswith("full_schemas"):
return [SCHEMA_VERSION]
return ["99_add_unicorn_to_database.sql"]
class WorkerSchemaTests(HomeserverTestCase):
def make_homeserver(self, reactor, clock):
hs = self.setup_test_homeserver(
@ -51,7 +70,7 @@ class WorkerSchemaTests(HomeserverTestCase):
prepare_database(db_conn, db_pool.engine, self.hs.config)
def test_not_upgraded(self):
def test_not_upgraded_old_schema_version(self):
"""Test that workers don't start if the DB has an older schema version"""
db_pool = self.hs.get_datastore().db_pool
db_conn = LoggingDatabaseConnection(
@ -67,3 +86,34 @@ class WorkerSchemaTests(HomeserverTestCase):
with self.assertRaises(PrepareDatabaseException):
prepare_database(db_conn, db_pool.engine, self.hs.config)
def test_not_upgraded_current_schema_version_with_outstanding_deltas(self):
"""
Test that workers don't start if the DB is on the current schema version,
but there are still outstanding delta migrations to run.
"""
db_pool = self.hs.get_datastore().db_pool
db_conn = LoggingDatabaseConnection(
db_pool._db_pool.connect(),
db_pool.engine,
"tests",
)
# Set the schema version of the database to the current version
cur = db_conn.cursor()
cur.execute("UPDATE schema_version SET version = ?", (SCHEMA_VERSION,))
db_conn.commit()
# Path `os.listdir` here to make synapse think that there is a migration
# file ready to be run.
# Note that we can't patch this function for the whole method, else Synapse
# will try to find the file when building the database initially.
with mock.patch("os.listdir", mock.Mock(side_effect=fake_listdir)):
with self.assertRaises(PrepareDatabaseException):
# Synapse should think that there is an outstanding migration file due to
# patching 'os.listdir' in the function decorator.
#
# We expect Synapse to raise an exception to indicate the master process
# needs to apply this migration file.
prepare_database(db_conn, db_pool.engine, self.hs.config)