Fix bug in quote_standby_name() function (#3161)

According to Postgres docs "ANY" and "FIRST" keywords are supposed to be double-quoted.

Ref: https://www.postgresql.org/docs/current/runtime-config-replication.html#GUC-SYNCHRONOUS-STANDBY-NAMES

patroni/postgresql/sync.py

@@ -8,7 +8,7 @@ from typing import Collection, List, NamedTuple, Optional, TYPE_CHECKING
 from .. import global_config
 from ..collections import CaseInsensitiveDict, CaseInsensitiveSet
 from ..dcs import Cluster
-from ..psycopg import quote_ident as _quote_ident
+from ..psycopg import quote_ident
 
 if TYPE_CHECKING:  # pragma: no cover
     from . import Postgresql
@@ -31,9 +31,14 @@ SYNC_REP_PARSER_RE = re.compile(r"""
         """, re.X)
 
 
-def quote_ident(value: str) -> str:
-    """Very simplified version of `psycopg` :func:`quote_ident` function."""
-    return value if SYNC_STANDBY_NAME_RE.match(value) else _quote_ident(value)
+def quote_standby_name(value: str) -> str:
+    """Quote provided *value* if it is nenecessary.
+
+    :param value: name of a synchronous standby.
+
+    :returns: a quoted value if it is required or the original one.
+    """
+    return value if SYNC_STANDBY_NAME_RE.match(value) and value.lower() not in ('first', 'any') else quote_ident(value)
 
 
 class _SSN(NamedTuple):
@@ -391,7 +396,7 @@ END;$$""")
         if has_asterisk:
             sync = ['*']
         else:
-            sync = [quote_ident(x) for x in sorted(sync)]
+            sync = [quote_standby_name(x) for x in sorted(sync)]
 
         if self._postgresql.supports_multiple_sync and len(sync) > 1:
             if num is None:

tests/test_sync.py

@@ -128,9 +128,9 @@ class TestSync(BaseTestPostgresql):
         self.assertEqual(value_in_conf(), "synchronous_standby_names = 'ANY 1 (*)'")
 
         mock_reload.reset_mock()
-        self.s.set_synchronous_standby_names(['a', 'b'], 1)
+        self.s.set_synchronous_standby_names(['any', 'b'], 1)
         mock_reload.assert_called()
-        self.assertEqual(value_in_conf(), "synchronous_standby_names = 'ANY 1 (a,b)'")
+        self.assertEqual(value_in_conf(), "synchronous_standby_names = 'ANY 1 (\"any\",b)'")
 
         mock_reload.reset_mock()
         self.s.set_synchronous_standby_names(['a', 'b'], 3)