Don't expose empty tags dict in API and DCS

patroni/api.py

@@ -63,7 +63,7 @@ class RestApiHandler(BaseHTTPRequestHandler):
 
         path = '/master' if self.path == '/' else self.path
         response = self.get_postgresql_status()
-        response['tags'] = self.server.patroni.tags
+        response.update(self.get_tags())
 
         patroni = self.server.patroni
         cluster = patroni.dcs.cluster
@@ -94,7 +94,7 @@ class RestApiHandler(BaseHTTPRequestHandler):
 
     def do_GET_patroni(self):
         response = self.get_postgresql_status(True)
-        response['tags'] = self.server.patroni.tags
+        response.update(self.get_tags())
         response['patroni'] = {'version': self.server.patroni.version, 'scope': self.server.patroni.postgresql.scope}
 
         self.send_response(200)
@@ -289,6 +289,9 @@ class RestApiHandler(BaseHTTPRequestHandler):
                 state = 'unknown'
             return {'state': state}
 
+    def get_tags(self):
+        return {'tags': self.server.patroni.tags} if self.server.patroni.tags else {}
+
     def log_message(self, fmt, *args):
         logger.debug("API thread: %s - - [%s] %s", self.client_address[0], self.log_date_time_string(), fmt % args)
 

patroni/ha.py

@@ -55,9 +55,10 @@ class Ha(object):
             'conn_url': self.state_handler.connection_string,
             'api_url': self.patroni.api.connection_string,
             'state': self.state_handler.state,
-            'role': self.state_handler.role,
-            'tags': self.patroni.tags
+            'role': self.state_handler.role
         }
+        if self.patroni.tags:
+            data['tags'] = self.patroni.tags
         if data['state'] in ['running', 'restarting', 'starting']:
             try:
                 data['xlog_location'] = self.state_handler.xlog_position()

tests/test_ha.py

@@ -52,7 +52,7 @@ class MockPatroni(object):
         self.postgresql = p
         self.dcs = d
         self.api = Mock()
-        self.tags = {}
+        self.tags = {'foo': 'bar'}
         self.nofailover = None
         self.nap_time = 10
         self.replicatefrom = None