Make sure only supported parameters are written to connection string (patroni#3207)

Close patroni#3206

Author: CyberDem0n

patroni/postgresql/config.py

@@ -617,7 +617,10 @@ def format_dsn(self, params: Dict[str, Any]) -> str:
         def escape(value: Any) -> str:
             return re.sub(r'([\'\\ ])', r'\\\1', str(value))
 
-        return ' '.join('{0}={1}'.format(kw, escape(params[kw])) for kw in keywords if params.get(kw) is not None)
+        key_ver = {'target_session_attrs': 100000, 'gssencmode': 120000, 'channel_binding': 130000,
+                   'sslpassword': 130000, 'sslcrldir': 140000, 'sslnegotiation': 170000}
+        return ' '.join('{0}={1}'.format(kw, escape(params[kw])) for kw in keywords
+                        if params.get(kw) is not None and self._postgresql.major_version >= key_ver.get(kw, 0))
 
     def _write_recovery_params(self, fd: ConfigWriter, recovery_params: CaseInsensitiveDict) -> None:
         if self._postgresql.major_version >= 90500:

tests/test_postgresql.py

@@ -1182,3 +1182,26 @@ def test_load_current_server_parameters(self):
         self.assertEqual(dict(self.p.config._recovery_params),
                          {'primary_conninfo': {'host': 'a', 'port': '5433', 'passfile': '/blabla', 'sslmode': 'prefer',
                           'gssencmode': 'prefer', 'channel_binding': 'prefer', 'sslnegotiation': 'postgres'}})
+
+    def test_format_dsn(self):
+        params = {'host': '1', 'port': 2, 'target_session_attrs': 'read-write', 'gssencmode': 'prefer',
+                  'channel_binding': 'prefer', 'sslpassword': 'pwd', 'sslcrldir': '/', 'sslnegotiation': 'postgres'}
+        self.p._major_version = 90600
+        self.assertEqual(self.p.config.format_dsn(params), 'host=1 port=2')
+        self.p._major_version = 100000
+        self.assertEqual(self.p.config.format_dsn(params), 'host=1 port=2 target_session_attrs=read-write')
+        self.p._major_version = 120000
+        self.assertEqual(self.p.config.format_dsn(params),
+                         'host=1 port=2 gssencmode=prefer target_session_attrs=read-write')
+        self.p._major_version = 130000
+        self.assertEqual(self.p.config.format_dsn(params),
+                         'host=1 port=2 sslpassword=pwd gssencmode=prefer '
+                         'channel_binding=prefer target_session_attrs=read-write')
+        self.p._major_version = 140000
+        self.assertEqual(self.p.config.format_dsn(params),
+                         'host=1 port=2 sslpassword=pwd sslcrldir=/ gssencmode=prefer '
+                         'channel_binding=prefer target_session_attrs=read-write')
+        self.p._major_version = 170000
+        self.assertEqual(self.p.config.format_dsn(params),
+                         'host=1 port=2 sslpassword=pwd sslcrldir=/ gssencmode=prefer channel_binding=prefer '
+                         'target_session_attrs=read-write sslnegotiation=postgres')