Support psycopg as a PostgreSQL driver

synapse/_scripts/synapse_port_db.py

@@ -1448,7 +1448,7 @@ def main() -> None:
     if "name" not in postgres_config:
         sys.stderr.write("Malformed database config: no 'name'\n")
         sys.exit(2)
-    if postgres_config["name"] != "psycopg2":
+    if postgres_config["name"] not in ("psycopg", "psycopg2"):
         sys.stderr.write("Database must use the 'psycopg2' connector.\n")
         sys.exit(3)
 

synapse/config/database.py

@@ -57,7 +57,7 @@ class DatabaseConnectionConfig:
     def __init__(self, name: str, db_config: dict):
         db_engine = db_config.get("name", "sqlite3")
 
-        if db_engine not in ("sqlite3", "psycopg2"):
+        if db_engine not in ("sqlite3", "psycopg2", "psycopg"):
             raise ConfigError("Unsupported database type %r" % (db_engine,))
 
         if db_engine == "sqlite3":

synapse/storage/engines/__init__.py

@@ -21,23 +21,35 @@
 from typing import Any, Mapping, NoReturn
 
 from ._base import BaseDatabaseEngine, IncorrectDatabaseSetup
+from .postgres import PostgresEngine
 
 # The classes `PostgresEngine` and `Sqlite3Engine` must always be importable, because
 # we use `isinstance(engine, PostgresEngine)` to write different queries for postgres
 # and sqlite. But the database driver modules are both optional: they may not be
 # installed. To account for this, create dummy classes on import failure so we can
 # still run `isinstance()` checks.
 try:
-    from .postgres import PostgresEngine
+    from .psycopg2 import Psycopg2Engine
 except ImportError:
 
-    class PostgresEngine(BaseDatabaseEngine):  # type: ignore[no-redef]
+    class Psycopg2Engine(BaseDatabaseEngine):  # type: ignore[no-redef]
         def __new__(cls, *args: object, **kwargs: object) -> NoReturn:
             raise RuntimeError(
                 f"Cannot create {cls.__name__} -- psycopg2 module is not installed"
             )
 
 
+try:
+    from .psycopg import PsycopgEngine
+except ImportError:
+
+    class PsycopgEngine(BaseDatabaseEngine):  # type: ignore[no-redef]
+        def __new__(cls, *args: object, **kwargs: object) -> NoReturn:
+            raise RuntimeError(
+                f"Cannot create {cls.__name__} -- psycopg module is not installed"
+            )
+
+
 try:
     from .sqlite import Sqlite3Engine
 except ImportError:
@@ -56,7 +68,10 @@ def create_engine(database_config: Mapping[str, Any]) -> BaseDatabaseEngine:
         return Sqlite3Engine(database_config)
 
     if name == "psycopg2":
-        return PostgresEngine(database_config)
+        return Psycopg2Engine(database_config)
+
+    if name == "psycopg":
+        return PsycopgEngine(database_config)
 
     raise RuntimeError("Unsupported database engine '%s'" % (name,))
 

synapse/storage/engines/_base.py

@@ -45,9 +45,12 @@ class IncorrectDatabaseSetup(RuntimeError):
 
 ConnectionType = TypeVar("ConnectionType", bound=Connection)
 CursorType = TypeVar("CursorType", bound=Cursor)
+IsolationLevelType = TypeVar("IsolationLevelType")
 
 
-class BaseDatabaseEngine(Generic[ConnectionType, CursorType], metaclass=abc.ABCMeta):
+class BaseDatabaseEngine(
+    Generic[ConnectionType, CursorType, IsolationLevelType], metaclass=abc.ABCMeta
+):
     def __init__(self, module: DBAPI2Module, config: Mapping[str, Any]):
         self.module = module
 
@@ -129,7 +132,7 @@ def attempt_to_set_autocommit(self, conn: ConnectionType, autocommit: bool) -> N
 
     @abc.abstractmethod
     def attempt_to_set_isolation_level(
-        self, conn: ConnectionType, isolation_level: Optional[int]
+        self, conn: ConnectionType, isolation_level: Optional[IsolationLevelType]
     ) -> None:
         """Attempt to set the connections isolation level.
 

synapse/storage/engines/postgres.py

@@ -19,18 +19,19 @@
 #
 #
 
+import abc
 import logging
-from typing import TYPE_CHECKING, Any, Mapping, NoReturn, Optional, Tuple, cast
-
-import psycopg2.extensions
+from typing import TYPE_CHECKING, Any, Generic, Mapping, Optional, Tuple, cast
 
 from synapse.storage.engines._base import (
     AUTO_INCREMENT_PRIMARY_KEYPLACEHOLDER,
     BaseDatabaseEngine,
+    ConnectionType,
+    CursorType,
     IncorrectDatabaseSetup,
-    IsolationLevel,
+    IsolationLevelType,
 )
-from synapse.storage.types import Cursor
+from synapse.storage.types import Cursor, DBAPI2Module
 
 if TYPE_CHECKING:
     from synapse.storage.database import LoggingDatabaseConnection
@@ -40,19 +41,16 @@
 
 
 class PostgresEngine(
-    BaseDatabaseEngine[psycopg2.extensions.connection, psycopg2.extensions.cursor]
+    Generic[ConnectionType, CursorType, IsolationLevelType],
+    BaseDatabaseEngine[ConnectionType, CursorType, IsolationLevelType],
+    metaclass=abc.ABCMeta,
 ):
-    def __init__(self, database_config: Mapping[str, Any]):
-        super().__init__(psycopg2, database_config)
-        psycopg2.extensions.register_type(psycopg2.extensions.UNICODE)
+    isolation_level_map: Mapping[int, IsolationLevelType]
+    default_isolation_level: IsolationLevelType
 
-        # Disables passing `bytes` to txn.execute, c.f.
-        # https://github.com/matrix-org/synapse/issues/6186. If you do
-        # actually want to use bytes than wrap it in `bytearray`.
-        def _disable_bytes_adapter(_: bytes) -> NoReturn:
-            raise Exception("Passing bytes to DB is disabled.")
+    def __init__(self, module: DBAPI2Module, database_config: Mapping[str, Any]):
+        super().__init__(module, database_config)
 
-        psycopg2.extensions.register_adapter(bytes, _disable_bytes_adapter)
         self.synchronous_commit: bool = database_config.get("synchronous_commit", True)
         # Set the statement timeout to 1 hour by default.
         # Any query taking more than 1 hour should probably be considered a bug;
@@ -65,19 +63,19 @@ def _disable_bytes_adapter(_: bytes) -> NoReturn:
         )
         self._version: Optional[int] = None  # unknown as yet
 
-        self.isolation_level_map: Mapping[int, int] = {
-            IsolationLevel.READ_COMMITTED: psycopg2.extensions.ISOLATION_LEVEL_READ_COMMITTED,
-            IsolationLevel.REPEATABLE_READ: psycopg2.extensions.ISOLATION_LEVEL_REPEATABLE_READ,
-            IsolationLevel.SERIALIZABLE: psycopg2.extensions.ISOLATION_LEVEL_SERIALIZABLE,
-        }
-        self.default_isolation_level = (
-            psycopg2.extensions.ISOLATION_LEVEL_REPEATABLE_READ
-        )
         self.config = database_config
 
-    def set_statement_timeout(self, cursor: Cursor, statement_timeout: int) -> None:
+    @abc.abstractmethod
+    def get_server_version(self, db_conn: ConnectionType) -> int:
+        """Gets called when setting up a brand new database. This allows us to
+        apply stricter checks on new databases versus existing database.
+        """
+        ...
+
+    @abc.abstractmethod
+    def set_statement_timeout(self, cursor: CursorType, statement_timeout: int) -> None:
         """Configure the current cursor's statement timeout."""
-        cursor.execute("SET statement_timeout TO ?", (statement_timeout,))
+        ...
 
     @property
     def single_threaded(self) -> bool:
@@ -92,21 +90,22 @@ def get_db_locale(self, txn: Cursor) -> Tuple[str, str]:
 
     def check_database(
         self,
-        db_conn: psycopg2.extensions.connection,
+        db_conn: ConnectionType,
         allow_outdated_version: bool = False,
     ) -> None:
         # Get the version of PostgreSQL that we're using. As per the psycopg2
         # docs: The number is formed by converting the major, minor, and
         # revision numbers into two-decimal-digit numbers and appending them
         # together. For example, version 8.1.5 will be returned as 80105
-        self._version = db_conn.server_version
+        self._version = self.get_server_version(db_conn)
         allow_unsafe_locale = self.config.get("allow_unsafe_locale", False)
 
         # Are we on a supported PostgreSQL version?
         if not allow_outdated_version and self._version < 110000:
             raise RuntimeError("Synapse requires PostgreSQL 11 or above.")
 
-        with db_conn.cursor() as txn:
+        # psycopg and psycopg2 both support using cursors as context managers.
+        with db_conn.cursor() as txn:  # type: ignore[attr-defined]
             txn.execute("SHOW SERVER_ENCODING")
             rows = txn.fetchall()
             if rows and rows[0][0] != "UTF8":
@@ -173,7 +172,8 @@ def convert_param_style(self, sql: str) -> str:
         return sql.replace("?", "%s")
 
     def on_new_connection(self, db_conn: "LoggingDatabaseConnection") -> None:
-        db_conn.set_isolation_level(self.default_isolation_level)
+        # mypy doesn't realize that ConnectionType matches the Connection protocol.
+        self.attempt_to_set_isolation_level(db_conn.conn, self.default_isolation_level)  # type: ignore[arg-type]
 
         # Set the bytea output to escape, vs the default of hex
         cursor = db_conn.cursor()
@@ -202,16 +202,9 @@ def supports_returning(self) -> bool:
         """Do we support the `RETURNING` clause in insert/update/delete?"""
         return True
 
-    def is_deadlock(self, error: Exception) -> bool:
-        if isinstance(error, psycopg2.DatabaseError):
-            # https://www.postgresql.org/docs/current/static/errcodes-appendix.html
-            # "40001" serialization_failure
-            # "40P01" deadlock_detected
-            return error.pgcode in ["40001", "40P01"]
-        return False
-
-    def is_connection_closed(self, conn: psycopg2.extensions.connection) -> bool:
-        return bool(conn.closed)
+    def is_connection_closed(self, conn: ConnectionType) -> bool:
+        # Both psycopg and psycopg2 connections have a closed attributed.
+        return bool(conn.closed)  # type: ignore[attr-defined]
 
     def lock_table(self, txn: Cursor, table: str) -> None:
         txn.execute("LOCK TABLE %s in EXCLUSIVE MODE" % (table,))
@@ -234,25 +227,8 @@ def server_version(self) -> str:
     def row_id_name(self) -> str:
         return "ctid"
 
-    def in_transaction(self, conn: psycopg2.extensions.connection) -> bool:
-        return conn.status != psycopg2.extensions.STATUS_READY
-
-    def attempt_to_set_autocommit(
-        self, conn: psycopg2.extensions.connection, autocommit: bool
-    ) -> None:
-        return conn.set_session(autocommit=autocommit)
-
-    def attempt_to_set_isolation_level(
-        self, conn: psycopg2.extensions.connection, isolation_level: Optional[int]
-    ) -> None:
-        if isolation_level is None:
-            isolation_level = self.default_isolation_level
-        else:
-            isolation_level = self.isolation_level_map[isolation_level]
-        return conn.set_isolation_level(isolation_level)
-
     @staticmethod
-    def executescript(cursor: psycopg2.extensions.cursor, script: str) -> None:
+    def executescript(cursor: CursorType, script: str) -> None:
         """Execute a chunk of SQL containing multiple semicolon-delimited statements.
 
         Psycopg2 seems happy to do this in DBAPI2's `execute()` function.

synapse/storage/engines/psycopg.py

@@ -0,0 +1,96 @@
+# Copyright 2022-2023 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.
+
+import logging
+from typing import Any, Mapping, Optional, Tuple
+
+import psycopg
+import psycopg.errors
+import psycopg.sql
+
+from twisted.enterprise.adbapi import Connection as TxConnection
+
+from synapse.storage.engines import PostgresEngine
+from synapse.storage.engines._base import IsolationLevel
+
+logger = logging.getLogger(__name__)
+
+
+class PsycopgEngine(
+    # mypy doesn't seem to like that the psycopg Connection and Cursor are Generics.
+    PostgresEngine[  # type: ignore[type-var]
+        psycopg.Connection[Tuple], psycopg.Cursor[Tuple], psycopg.IsolationLevel
+    ]
+):
+    def __init__(self, database_config: Mapping[str, Any]):
+        super().__init__(psycopg, database_config)  # type: ignore[arg-type]
+        # psycopg2.extensions.register_type(psycopg2.extensions.UNICODE)
+
+        # Disables passing `bytes` to txn.execute, c.f. #6186. If you do
+        # actually want to use bytes than wrap it in `bytearray`.
+        # def _disable_bytes_adapter(_: bytes) -> NoReturn:
+        #     raise Exception("Passing bytes to DB is disabled.")
+
+        self.isolation_level_map = {
+            IsolationLevel.READ_COMMITTED: psycopg.IsolationLevel.READ_COMMITTED,
+            IsolationLevel.REPEATABLE_READ: psycopg.IsolationLevel.REPEATABLE_READ,
+            IsolationLevel.SERIALIZABLE: psycopg.IsolationLevel.SERIALIZABLE,
+        }
+        self.default_isolation_level = psycopg.IsolationLevel.REPEATABLE_READ
+
+    def get_server_version(self, db_conn: psycopg.Connection) -> int:
+        return db_conn.info.server_version
+
+    def set_statement_timeout(
+        self, cursor: psycopg.Cursor, statement_timeout: int
+    ) -> None:
+        """Configure the current cursor's statement timeout."""
+        cursor.execute(
+            psycopg.sql.SQL("SET statement_timeout TO {}").format(statement_timeout)
+        )
+
+    def convert_param_style(self, sql: str) -> str:
+        # if isinstance(sql, psycopg.sql.Composed):
+        #     return sql
+
+        return sql.replace("?", "%s")
+
+    def is_deadlock(self, error: Exception) -> bool:
+        if isinstance(error, psycopg.errors.Error):
+            # https://www.postgresql.org/docs/current/static/errcodes-appendix.html
+            # "40001" serialization_failure
+            # "40P01" deadlock_detected
+            return error.sqlstate in ["40001", "40P01"]
+        return False
+
+    def in_transaction(self, conn: psycopg.Connection) -> bool:
+        return conn.info.transaction_status != psycopg.pq.TransactionStatus.IDLE
+
+    def attempt_to_set_autocommit(
+        self, conn: psycopg.Connection, autocommit: bool
+    ) -> None:
+        # Sometimes this gets called with a Twisted connection instead, unwrap
+        # it because it doesn't support __setattr__.
+        if isinstance(conn, TxConnection):
+            conn = conn._connection
+        conn.autocommit = autocommit
+
+    def attempt_to_set_isolation_level(
+        self, conn: psycopg.Connection, isolation_level: Optional[int]
+    ) -> None:
+        if isolation_level is None:
+            pg_isolation_level = self.default_isolation_level
+        else:
+            pg_isolation_level = self.isolation_level_map[isolation_level]
+        conn.isolation_level = pg_isolation_level