port freeze function to python

nominatim/cli.py

@@ -173,27 +173,6 @@ class SetupAll:
         return run_legacy_script(*params, nominatim_env=args)
 
 
-class SetupFreeze:
-    """\
-    Make database read-only.
-
-    About half of data in the Nominatim database is kept only to be able to
-    keep the data up-to-date with new changes made in OpenStreetMap. This
-    command drops all this data and only keeps the part needed for geocoding
-    itself.
-
-    This command has the same effect as the `--no-updates` option for imports.
-    """
-
-    @staticmethod
-    def add_args(parser):
-        pass # No options
-
-    @staticmethod
-    def run(args):
-        return run_legacy_script('setup.php', '--drop', nominatim_env=args)
-
-
 class SetupSpecialPhrases:
     """\
     Maintain special phrases.
@@ -352,7 +331,7 @@ def nominatim(**kwargs):
     parser = CommandlineParser('nominatim', nominatim.__doc__)
 
     parser.add_subcommand('import', SetupAll)
-    parser.add_subcommand('freeze', SetupFreeze)
+    parser.add_subcommand('freeze', clicmd.SetupFreeze)
     parser.add_subcommand('replication', clicmd.UpdateReplication)
 
     parser.add_subcommand('special-phrases', SetupSpecialPhrases)

nominatim/clicmd/__init__.py

@@ -7,3 +7,4 @@ from .api import APISearch, APIReverse, APILookup, APIDetails, APIStatus
 from .index import UpdateIndex
 from .refresh import UpdateRefresh
 from .admin import AdminFuncs
+from .freeze import SetupFreeze

nominatim/clicmd/freeze.py

@@ -0,0 +1,37 @@
+"""
+Implementation of the 'freeze' subcommand.
+"""
+
+from ..db.connection import connect
+
+# Do not repeat documentation of subcommand classes.
+# pylint: disable=C0111
+# Using non-top-level imports to avoid eventually unused imports.
+# pylint: disable=E0012,C0415
+
+class SetupFreeze:
+    """\
+    Make database read-only.
+
+    About half of data in the Nominatim database is kept only to be able to
+    keep the data up-to-date with new changes made in OpenStreetMap. This
+    command drops all this data and only keeps the part needed for geocoding
+    itself.
+
+    This command has the same effect as the `--no-updates` option for imports.
+    """
+
+    @staticmethod
+    def add_args(parser):
+        pass # No options
+
+    @staticmethod
+    def run(args):
+        from ..tools import freeze
+
+        conn = connect(args.config.get_libpq_dsn())
+        freeze.drop_update_tables(conn)
+        freeze.drop_flatnode_file(args.config.FLATNODE_FILE)
+        conn.close()
+
+        return 0

nominatim/tools/freeze.py

@@ -0,0 +1,43 @@
+"""
+Functions for removing unnecessary data from the database.
+"""
+from pathlib import Path
+
+UPDATE_TABLES = [
+    'address_levels',
+    'gb_postcode',
+    'import_osmosis_log',
+    'import_polygon_%',
+    'location_area%',
+    'location_road%',
+    'place',
+    'planet_osm_%',
+    'search_name_%',
+    'us_postcode',
+    'wikipedia_%'
+]
+
+def drop_update_tables(conn):
+    """ Drop all tables only necessary for updating the database from
+        OSM replication data.
+    """
+
+    where = ' or '.join(["(tablename LIKE '{}')".format(t) for t in UPDATE_TABLES])
+
+    with conn.cursor() as cur:
+        cur.execute("SELECT tablename FROM pg_tables WHERE " + where)
+        tables = [r[0] for r in cur]
+
+        for table in tables:
+            cur.execute('DROP TABLE IF EXISTS "{}" CASCADE'.format(table))
+
+    conn.commit()
+
+
+def drop_flatnode_file(fname):
+    """ Remove the flatnode file if it exists.
+    """
+    if fname:
+        fpath = Path(fname)
+        if fpath.exists():
+            fpath.unlink()