reorganize api submodule

Use a directory for the submodule where the __init__ file contains
the public API. This makes it easier to separate public interface
from the internal implementation.

nominatim/api/status.py

@@ -0,0 +1,64 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# This file is part of Nominatim. (https://nominatim.org)
+#
+# Copyright (C) 2023 by the Nominatim developer community.
+# For a full list of authors see the git log.
+"""
+Classes and function releated to status call.
+"""
+from typing import Optional, cast
+import datetime as dt
+
+import sqlalchemy as sa
+from sqlalchemy.ext.asyncio.engine import AsyncConnection
+import asyncpg
+
+from nominatim import version
+
+class StatusResult:
+    """ Result of a call to the status API.
+    """
+
+    def __init__(self, status: int, msg: str):
+        self.status = status
+        self.message = msg
+        self.software_version = version.NOMINATIM_VERSION
+        self.data_updated: Optional[dt.datetime]  = None
+        self.database_version: Optional[version.NominatimVersion] = None
+
+
+async def _get_database_date(conn: AsyncConnection) -> Optional[dt.datetime]:
+    """ Query the database date.
+    """
+    sql = sa.text('SELECT lastimportdate FROM import_status LIMIT 1')
+    result = await conn.execute(sql)
+
+    for row in result:
+        return cast(dt.datetime, row[0])
+
+    return None
+
+
+async def _get_database_version(conn: AsyncConnection) -> Optional[version.NominatimVersion]:
+    sql = sa.text("""SELECT value FROM nominatim_properties
+                     WHERE property = 'database_version'""")
+    result = await conn.execute(sql)
+
+    for row in result:
+        return version.parse_version(cast(str, row[0]))
+
+    return None
+
+
+async def get_status(conn: AsyncConnection) -> StatusResult:
+    """ Execute a status API call.
+    """
+    status = StatusResult(0, 'OK')
+    try:
+        status.data_updated = await _get_database_date(conn)
+        status.database_version = await _get_database_version(conn)
+    except asyncpg.PostgresError:
+        return StatusResult(700, 'Database connection failed')
+
+    return status