fix style issue found by flake8

[nominatim.git] / src / nominatim_db / db / connection.py

diff --git a/src/nominatim_db/db/connection.py b/src/nominatim_db/db/connection.py
index 19fcddd44c7bd790c2b77224a7dbad58a48f3063..e960a3fa8a1186450a67b749754155975e8327b8 100644 (file)
--- a/src/nominatim_db/db/connection.py
+++ b/src/nominatim_db/db/connection.py
@@ -7,200 +7,139 @@
 """
 Specialised connection and cursor functions.
 """
 """
 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 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()
 
 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'))
-
-        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)
+Cursor = psycopg.Cursor[Any]
+Connection = psycopg.Connection[Any]

 
 
 
 

-    def scalar(self, sql: 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.
-        """
-        self.execute(sql, args)
+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(row_factory=psycopg.rows.tuple_row) as cur:
+        cur.execute(sql, args)

 
 

-        if self.rowcount != 1:
+        if cur.rowcount != 1:

             raise RuntimeError("Query did not return a single row.")
 
             raise RuntimeError("Query did not return a single row.")
 

-        result = self.fetchone()
-        assert result is not None
-
-        return result[0]
+        result = cur.fetchone()

 
 

+    assert result is not None
+    return result[0]

 
 

-    def drop_table(self, name: str, if_exists: bool = True, cascade: bool = False) -> None:
-        """ Drop the table with the given name.
-            Set `if_exists` to False if a non-existent table should raise
-            an exception instead of just being ignored. If 'cascade' is set
-            to True then all dependent tables are deleted as well.
-        """
-        sql = 'DROP TABLE '
-        if if_exists:
-            sql += 'IF EXISTS '
-        sql += '{}'
-        if cascade:
-            sql += ' CASCADE'

 
 

-        self.execute(pysql.SQL(sql).format(pysql.Identifier(name)))
+def table_exists(conn: Connection, table: str) -> bool:
+    """ Check that a table with the given name exists in the database.
+    """
+    num = execute_scalar(
+        conn,
+        """SELECT count(*) FROM pg_tables
+           WHERE tablename = %s and schemaname = 'public'""", (table, ))
+    return num == 1 if isinstance(num, int) else False

 
 
 
 

-class Connection(psycopg2.extensions.connection):
-    """ A connection that provides the specialised cursor by default and
-        adds convenience functions for administrating the database.
+def table_has_column(conn: Connection, table: str, column: str) -> bool:
+    """ Check if the table 'table' exists and has a column with name 'column'.

     """
     """

-    @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 table_exists(self, table: str) -> bool:
-        """ Check that a table with the given name exists in the database.
-        """
-        with self.cursor() as cur:
-            num = cur.scalar("""SELECT count(*) FROM pg_tables
-                                WHERE tablename = %s and schemaname = 'public'""", (table, ))
-            return num == 1 if isinstance(num, int) else False
-
-
-    def table_has_column(self, table: str, column: str) -> bool:
-        """ Check if the table 'table' exists and has a column with name 'column'.
-        """
-        with self.cursor() as cur:
-            has_column = cur.scalar("""SELECT count(*) FROM information_schema.columns
-                                       WHERE table_name = %s
-                                             and column_name = %s""",
-                                    (table, column))
-            return has_column > 0 if isinstance(has_column, int) else False
-
-
-    def index_exists(self, index: str, table: Optional[str] = None) -> bool:
-        """ Check that an index with the given name exists in the database.
-            If table is not None then the index must relate to the given
-            table.
-        """
-        with self.cursor() as cur:
-            cur.execute("""SELECT tablename FROM pg_indexes
-                           WHERE indexname = %s and schemaname = 'public'""", (index, ))
-            if cur.rowcount == 0:
-                return False
+    has_column = execute_scalar(conn,
+                                """SELECT count(*) FROM information_schema.columns
+                                   WHERE table_name = %s and column_name = %s""",
+                                (table, column))
+    return has_column > 0 if isinstance(has_column, int) else False

 
 

-            if table is not None:
-                row = cur.fetchone()
-                if row is None or not isinstance(row[0], str):
-                    return False
-                return row[0] == table

 
 

-        return True
+def index_exists(conn: Connection, index: str, table: Optional[str] = None) -> bool:
+    """ Check that an index with the given name exists in the database.
+        If table is not None then the index must relate to the given
+        table.
+    """
+    with conn.cursor() as cur:
+        cur.execute("""SELECT tablename FROM pg_indexes
+                       WHERE indexname = %s and schemaname = 'public'""", (index, ))
+        if cur.rowcount == 0:
+            return False
+
+        if table is not None:
+            row = cur.fetchone()
+            if row is None or not isinstance(row[0], str):
+                return False
+            return row[0] == table

 
 

+    return True

 
 

-    def drop_table(self, name: str, if_exists: bool = True, cascade: bool = False) -> None:
-        """ Drop the table with the given name.
-            Set `if_exists` to False if a non-existent table should raise
-            an exception instead of just being ignored.
-        """
-        with self.cursor() as cur:
-            cur.drop_table(name, if_exists, cascade)
-        self.commit()

 
 

+def drop_tables(conn: Connection, *names: str,
+                if_exists: bool = True, cascade: bool = False) -> None:
+    """ Drop one or more tables with the given names.
+        Set `if_exists` to False if a non-existent table should raise
+        an exception instead of just being ignored. `cascade` will cause
+        depended objects to be dropped as well.
+        The caller needs to take care of committing the change.
+    """
+    sql = pysql.SQL('DROP TABLE%s{}%s' % (
+                        ' IF EXISTS ' if if_exists else ' ',
+                        ' CASCADE' if cascade else ''))

 
 

-    def server_version_tuple(self) -> Tuple[int, int]:
-        """ Return the server version as a tuple of (major, minor).
-            Converts correctly for pre-10 and post-10 PostgreSQL versions.
-        """
-        version = self.server_version
-        if version < 100000:
-            return (int(version / 10000), int((version % 10000) / 100))
+    with conn.cursor() as cur:
+        for name in names:
+            cur.execute(sql.format(pysql.Identifier(name)))

 
 

-        return (int(version / 10000), version % 10000)

 
 

+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.info.server_version
+    if version < 100000:
+        return (int(version / 10000), int((version % 10000) / 100))

 
 

-    def postgis_version_tuple(self) -> Tuple[int, int]:
-        """ Return the postgis version installed in the database as a
-            tuple of (major, minor). Assumes that the PostGIS extension
-            has been installed already.
-        """
-        with self.cursor() as cur:
-            version = cur.scalar('SELECT postgis_lib_version()')
+    return (int(version / 10000), version % 10000)

 
 

-        version_parts = version.split('.')
-        if len(version_parts) < 2:
-            raise UsageError(f"Error fetching Postgis version. Bad format: {version}")

 
 

-        return (int(version_parts[0]), int(version_parts[1]))
+def postgis_version_tuple(conn: Connection) -> Tuple[int, int]:
+    """ Return the postgis version installed in the database as a
+        tuple of (major, minor). Assumes that the PostGIS extension
+        has been installed already.
+    """
+    version = execute_scalar(conn, 'SELECT postgis_lib_version()')

 
 

+    version_parts = version.split('.')
+    if len(version_parts) < 2:
+        raise UsageError(f"Error fetching Postgis version. Bad format: {version}")

 
 

-    def extension_loaded(self, extension_name: str) -> bool:
-        """ Return True if the hstore extension is loaded in the database.
-        """
-        with self.cursor() as cur:
-            cur.execute('SELECT extname FROM pg_extension WHERE extname = %s', (extension_name, ))
-            return cur.rowcount > 0
+    return (int(version_parts[0]), int(version_parts[1]))

 
 
 
 

-class ConnectionContext(ContextManager[Connection]):
-    """ Context manager of the connection that also provides direct access
-        to the underlying connection.
+def register_hstore(conn: Connection) -> None:
+    """ Register the hstore type with psycopg for the connection.

     """
     """

-    connection: Connection
+    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)

 
 

-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:
     """ 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
 
 
         raise UsageError(f"Cannot connect to database: {err}") from err
 
 


@@ -245,10 +184,18 @@ def get_pg_env(dsn: str,
     """
     env = dict(base_env if base_env is not None else os.environ)
 
     """
     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:
         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
         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)