feeder: add option post-sync-commands (#56164)

Exemple:

  [wcs-olap]
  post-sync-commands = ALTER DEFAULT PRIVILEGES IN SCHEMA {schema} GRANT SELECT ON TABLES TO user;
    GRANT USAGE ON SCHEMA {schema} TO user;
    GRANT SELECT ON ALL TABLES IN SCHEMA {schema}  TO user;

Those commands will be launched after the synchronization, interpolation
variables are usable (like {schema} for the target schema name).

tests/test_feeder.py

@@ -1,4 +1,5 @@
 import logging
+from unittest import mock
 
 import pytest
 
@@ -20,3 +21,23 @@ def test_sql_error_logging(caplog):
     with pytest.raises(Exception):
         feeder.ex('COIN')
     assert 'Failed to execute' in caplog.text
+
+
+def test_post_sync_commands(mock_cursor_execute, wcs, postgres_db, olap_cmd):
+    with olap_cmd.config() as config:
+        config.set(
+            'wcs-olap',
+            'post-sync-commands',
+            "NOTIFY coucou, '{schema}';\nSELECT * FROM information_schema.tables")
+
+    queries = []
+
+    def side_effect(query, *args, **kwargs):
+        queries.append(query)
+        return mock.DEFAULT
+
+    with mock_cursor_execute(side_effect=side_effect):
+        assert olap_cmd() == 0
+
+    # verify post-sync-commands are in the last executed queries
+    assert queries[-1] == "NOTIFY coucou, 'olap';\nSELECT * FROM information_schema.tables"

wcs_olap/feeder.py

@@ -632,6 +632,9 @@ class WcsOlapFeeder(object):
                         model_path = os.path.join(self.config['cubes_model_dirs'], '%s.model' % self.schema)
                         with open(model_path, 'w') as f:
                             json.dump(self.model, f, indent=2, sort_keys=True)
+                post_sync_commands = self.config.get('post-sync-commands')
+                if post_sync_commands:
+                    self.ex(post_sync_commands)
         finally:
             # prevent connection from remaining open
             self.cur.close()