port code to psycopg3

src/nominatim_db/db/connection.py

@@ -7,73 +7,27 @@
 """
 Specialised connection and cursor functions.
 """
-from typing import Optional, Any, Callable, ContextManager, Dict, cast, overload,\
-                   Tuple, Iterable
-import contextlib
+from typing import Optional, Any, Dict, Tuple
 import logging
 import os
 
-import psycopg2
-import psycopg2.extensions
-import psycopg2.extras
-from psycopg2 import sql as pysql
+import psycopg
+import psycopg.types.hstore
+from psycopg import sql as pysql
 
-from ..typing import SysEnv, Query, T_cursor
+from ..typing import SysEnv
 from ..errors import UsageError
 
 LOG = logging.getLogger()
 
-class Cursor(psycopg2.extras.DictCursor):
-    """ A cursor returning dict-like objects and providing specialised
-        execution functions.
-    """
-    # pylint: disable=arguments-renamed,arguments-differ
-    def execute(self, query: Query, args: Any = None) -> None:
-        """ Query execution that logs the SQL query when debugging is enabled.
-        """
-        if LOG.isEnabledFor(logging.DEBUG):
-            LOG.debug(self.mogrify(query, args).decode('utf-8'))
+Cursor = psycopg.Cursor[Any]
+Connection = psycopg.Connection[Any]
 
-        super().execute(query, args)
-
-
-    def execute_values(self, sql: Query, argslist: Iterable[Tuple[Any, ...]],
-                       template: Optional[Query] = None) -> None:
-        """ Wrapper for the psycopg2 convenience function to execute
-            SQL for a list of values.
-        """
-        LOG.debug("SQL execute_values(%s, %s)", sql, argslist)
-
-        psycopg2.extras.execute_values(self, sql, argslist, template=template)
-
-
-class Connection(psycopg2.extensions.connection):
-    """ A connection that provides the specialised cursor by default and
-        adds convenience functions for administrating the database.
-    """
-    @overload # type: ignore[override]
-    def cursor(self) -> Cursor:
-        ...
-
-    @overload
-    def cursor(self, name: str) -> Cursor:
-        ...
-
-    @overload
-    def cursor(self, cursor_factory: Callable[..., T_cursor]) -> T_cursor:
-        ...
-
-    def cursor(self, cursor_factory  = Cursor, **kwargs): # type: ignore
-        """ Return a new cursor. By default the specialised cursor is returned.
-        """
-        return super().cursor(cursor_factory=cursor_factory, **kwargs)
-
-
-def execute_scalar(conn: Connection, sql: Query, args: Any = None) -> Any:
+def execute_scalar(conn: Connection, sql: psycopg.abc.Query, args: Any = None) -> Any:
     """ Execute query that returns a single value. The value is returned.
         If the query yields more than one row, a ValueError is raised.
     """
-    with conn.cursor() as cur:
+    with conn.cursor(row_factory=psycopg.rows.tuple_row) as cur:
         cur.execute(sql, args)
 
         if cur.rowcount != 1:
@@ -144,7 +98,7 @@ def server_version_tuple(conn: Connection) -> Tuple[int, int]:
     """ Return the server version as a tuple of (major, minor).
         Converts correctly for pre-10 and post-10 PostgreSQL versions.
     """
-    version = conn.server_version
+    version = conn.info.server_version
     if version < 100000:
         return (int(version / 10000), int((version % 10000) / 100))
 
@@ -164,31 +118,25 @@ def postgis_version_tuple(conn: Connection) -> Tuple[int, int]:
 
     return (int(version_parts[0]), int(version_parts[1]))
 
+
 def register_hstore(conn: Connection) -> None:
     """ Register the hstore type with psycopg for the connection.
     """
-    psycopg2.extras.register_hstore(conn)
+    info = psycopg.types.TypeInfo.fetch(conn, "hstore")
+    if info is None:
+        raise RuntimeError('Hstore extension is requested but not installed.')
+    psycopg.types.hstore.register_hstore(info, conn)
 
 
-class ConnectionContext(ContextManager[Connection]):
-    """ Context manager of the connection that also provides direct access
-        to the underlying connection.
-    """
-    connection: Connection
-
-
-def connect(dsn: str) -> ConnectionContext:
+def connect(dsn: str, **kwargs: Any) -> Connection:
     """ Open a connection to the database using the specialised connection
         factory. The returned object may be used in conjunction with 'with'.
         When used outside a context manager, use the `connection` attribute
         to get the connection.
     """
     try:
-        conn = psycopg2.connect(dsn, connection_factory=Connection)
-        ctxmgr = cast(ConnectionContext, contextlib.closing(conn))
-        ctxmgr.connection = conn
-        return ctxmgr
-    except psycopg2.OperationalError as err:
+        return psycopg.connect(dsn, row_factory=psycopg.rows.namedtuple_row, **kwargs)
+    except psycopg.OperationalError as err:
         raise UsageError(f"Cannot connect to database: {err}") from err
 
 
@@ -233,10 +181,18 @@ def get_pg_env(dsn: str,
     """
     env = dict(base_env if base_env is not None else os.environ)
 
-    for param, value in psycopg2.extensions.parse_dsn(dsn).items():
+    for param, value in psycopg.conninfo.conninfo_to_dict(dsn).items():
         if param in _PG_CONNECTION_STRINGS:
-            env[_PG_CONNECTION_STRINGS[param]] = value
+            env[_PG_CONNECTION_STRINGS[param]] = str(value)
         else:
             LOG.error("Unknown connection parameter '%s' ignored.", param)
 
     return env
+
+
+async def run_async_query(dsn: str, query: psycopg.abc.Query) -> None:
+    """ Open a connection to the database and run a single query
+        asynchronously.
+    """
+    async with await psycopg.AsyncConnection.connect(dsn) as aconn:
+        await aconn.execute(query)