reduce from 3 to 2 packages

src/nominatim_db/db/status.py

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+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+# This file is part of Nominatim. (https://nominatim.org)
+#
+# Copyright (C) 2024 by the Nominatim developer community.
+# For a full list of authors see the git log.
+"""
+Access and helper functions for the status and status log table.
+"""
+from typing import Optional, Tuple, cast
+import datetime as dt
+import logging
+import re
+
+from .connection import Connection
+from ..utils.url_utils import get_url
+from ..errors import UsageError
+from ..typing import TypedDict
+
+LOG = logging.getLogger()
+ISODATE_FORMAT = '%Y-%m-%dT%H:%M:%S'
+
+
+class StatusRow(TypedDict):
+    """ Dictionary of columns of the import_status table.
+    """
+    lastimportdate: dt.datetime
+    sequence_id: Optional[int]
+    indexed: Optional[bool]
+
+
+def compute_database_date(conn: Connection, offline: bool = False) -> dt.datetime:
+    """ Determine the date of the database from the newest object in the
+        data base.
+    """
+    # If there is a date from osm2pgsql available, use that.
+    if conn.table_exists('osm2pgsql_properties'):
+        with conn.cursor() as cur:
+            cur.execute(""" SELECT value FROM osm2pgsql_properties
+                            WHERE property = 'current_timestamp' """)
+            row = cur.fetchone()
+            if row is not None:
+                return dt.datetime.strptime(row[0], "%Y-%m-%dT%H:%M:%SZ")\
+                                  .replace(tzinfo=dt.timezone.utc)
+
+    if offline:
+        raise UsageError("Cannot determine database date from data in offline mode.")
+
+    # Else, find the node with the highest ID in the database
+    with conn.cursor() as cur:
+        if conn.table_exists('place'):
+            osmid = cur.scalar("SELECT max(osm_id) FROM place WHERE osm_type='N'")
+        else:
+            osmid = cur.scalar("SELECT max(osm_id) FROM placex WHERE osm_type='N'")
+
+        if osmid is None:
+            LOG.fatal("No data found in the database.")
+            raise UsageError("No data found in the database.")
+
+    LOG.info("Using node id %d for timestamp lookup", osmid)
+    # Get the node from the API to find the timestamp when it was created.
+    node_url = f'https://www.openstreetmap.org/api/0.6/node/{osmid}/1'
+    data = get_url(node_url)
+
+    match = re.search(r'timestamp="((\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2}))Z"', data)
+
+    if match is None:
+        LOG.fatal("The node data downloaded from the API does not contain valid data.\n"
+                  "URL used: %s", node_url)
+        raise UsageError("Bad API data.")
+
+    LOG.debug("Found timestamp %s", match.group(1))
+
+    return dt.datetime.strptime(match.group(1), ISODATE_FORMAT).replace(tzinfo=dt.timezone.utc)
+
+
+def set_status(conn: Connection, date: Optional[dt.datetime],
+               seq: Optional[int] = None, indexed: bool = True) -> None:
+    """ Replace the current status with the given status. If date is `None`
+        then only sequence and indexed will be updated as given. Otherwise
+        the whole status is replaced.
+        The change will be committed to the database.
+    """
+    assert date is None or date.tzinfo == dt.timezone.utc
+    with conn.cursor() as cur:
+        if date is None:
+            cur.execute("UPDATE import_status set sequence_id = %s, indexed = %s",
+                        (seq, indexed))
+        else:
+            cur.execute("TRUNCATE TABLE import_status")
+            cur.execute("""INSERT INTO import_status (lastimportdate, sequence_id, indexed)
+                           VALUES (%s, %s, %s)""", (date, seq, indexed))
+
+    conn.commit()
+
+
+def get_status(conn: Connection) -> Tuple[Optional[dt.datetime], Optional[int], Optional[bool]]:
+    """ Return the current status as a triple of (date, sequence, indexed).
+        If status has not been set up yet, a triple of None is returned.
+    """
+    with conn.cursor() as cur:
+        cur.execute("SELECT * FROM import_status LIMIT 1")
+        if cur.rowcount < 1:
+            return None, None, None
+
+        row = cast(StatusRow, cur.fetchone())
+        return row['lastimportdate'], row['sequence_id'], row['indexed']
+
+
+def set_indexed(conn: Connection, state: bool) -> None:
+    """ Set the indexed flag in the status table to the given state.
+    """
+    with conn.cursor() as cur:
+        cur.execute("UPDATE import_status SET indexed = %s", (state, ))
+    conn.commit()
+
+
+def log_status(conn: Connection, start: dt.datetime,
+               event: str, batchsize: Optional[int] = None) -> None:
+    """ Write a new status line to the `import_osmosis_log` table.
+    """
+    with conn.cursor() as cur:
+        cur.execute("""INSERT INTO import_osmosis_log
+                       (batchend, batchseq, batchsize, starttime, endtime, event)
+                       SELECT lastimportdate, sequence_id, %s, %s, now(), %s FROM import_status""",
+                    (batchsize, start, event))
+    conn.commit()