MatrixSynapse/synapse/storage/databases/__init__.py

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# Copyright 2019 The Matrix.org Foundation C.I.C.
#
# 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.
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import logging
from typing import TYPE_CHECKING, Generic, List, Optional, Type, TypeVar
from synapse.storage._base import SQLBaseStore
from synapse.storage.database import DatabasePool, make_conn
from synapse.storage.databases.main.events import PersistEventsStore
from synapse.storage.databases.state import StateGroupDataStore
from synapse.storage.engines import create_engine
from synapse.storage.prepare_database import prepare_database
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if TYPE_CHECKING:
from synapse.server import HomeServer
logger = logging.getLogger(__name__)
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DataStoreT = TypeVar("DataStoreT", bound=SQLBaseStore, covariant=True)
class Databases(Generic[DataStoreT]):
"""The various databases.
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These are low level interfaces to physical databases.
Attributes:
databases
main
state
persist_events
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"""
databases: List[DatabasePool]
main: DataStoreT
state: StateGroupDataStore
persist_events: Optional[PersistEventsStore]
def __init__(self, main_store_class: Type[DataStoreT], hs: "HomeServer"):
# Note we pass in the main store class here as workers use a different main
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# store.
self.databases = []
main: Optional[DataStoreT] = None
state: Optional[StateGroupDataStore] = None
persist_events: Optional[PersistEventsStore] = None
for database_config in hs.config.database.databases:
db_name = database_config.name
engine = create_engine(database_config.config)
with make_conn(database_config, engine, "startup") as db_conn:
logger.info("[database config %r]: Checking database server", db_name)
engine.check_database(db_conn)
logger.info(
"[database config %r]: Preparing for databases %r",
db_name,
database_config.databases,
)
prepare_database(
db_conn,
engine,
hs.config,
databases=database_config.databases,
)
database = DatabasePool(hs, database_config, engine)
if "main" in database_config.databases:
logger.info(
"[database config %r]: Starting 'main' database", db_name
)
# Sanity check we don't try and configure the main store on
# multiple databases.
if main:
raise Exception("'main' data store already configured")
main = main_store_class(database, db_conn, hs)
# If we're on a process that can persist events also
# instantiate a `PersistEventsStore`
if hs.get_instance_name() in hs.config.worker.writers.events:
persist_events = PersistEventsStore(hs, database, main, db_conn)
if "state" in database_config.databases:
logger.info(
"[database config %r]: Starting 'state' database", db_name
)
# Sanity check we don't try and configure the state store on
# multiple databases.
if state:
raise Exception("'state' data store already configured")
state = StateGroupDataStore(database, db_conn, hs)
db_conn.commit()
self.databases.append(database)
logger.info("[database config %r]: prepared", db_name)
# Closing the context manager doesn't close the connection.
# psycopg will close the connection when the object gets GCed, but *only*
# if the PID is the same as when the connection was opened [1], and
# it may not be if we fork in the meantime.
#
# [1]: https://github.com/psycopg/psycopg2/blob/2_8_5/psycopg/connection_type.c#L1378
db_conn.close()
# Sanity check that we have actually configured all the required stores.
if not main:
raise Exception("No 'main' database configured")
if not state:
raise Exception("No 'state' database configured")
# We use local variables here to ensure that the databases do not have
# optional types.
self.main = main
self.state = state
self.persist_events = persist_events