Improve alternative URL description

Author: marceloneppel

src/cluster.py

@@ -166,7 +166,7 @@ def get_member_ip(self, member_name: str) -> str:
         # Request info from cluster endpoint (which returns all members of the cluster).
         for attempt in Retrying(stop=stop_after_attempt(len(self.peers_ips) + 1)):
             with attempt:
-                url = self._get_alternative_server_url(attempt)
+                url = self._get_alternative_patroni_url(attempt)
                 cluster_status = requests.get(f"{url}/cluster", verify=self.verify, timeout=10)
                 for member in cluster_status.json()["members"]:
                     if member["name"] == member_name:
@@ -187,7 +187,7 @@ def get_primary(self, unit_name_pattern=False) -> str:
         # Request info from cluster endpoint (which returns all members of the cluster).
         for attempt in Retrying(stop=stop_after_attempt(len(self.peers_ips) + 1)):
             with attempt:
-                url = self._get_alternative_server_url(attempt)
+                url = self._get_alternative_patroni_url(attempt)
                 cluster_status = requests.get(f"{url}/cluster", verify=self.verify, timeout=10)
                 for member in cluster_status.json()["members"]:
                     if member["role"] == "leader":
@@ -198,8 +198,12 @@ def get_primary(self, unit_name_pattern=False) -> str:
                         break
         return primary
 
-    def _get_alternative_server_url(self, attempt: AttemptManager) -> str:
-        """Get an alternative URL from another member each time."""
+    def _get_alternative_patroni_url(self, attempt: AttemptManager) -> str:
+        """Get an alternative REST API URL from another member each time.
+
+        When the Patroni process is not running in the current unit it's needed
+        to use a URL from another cluster member REST API to do some operations.
+        """
         if attempt.retry_state.attempt_number > 1:
             url = self._patroni_url.replace(
                 self.unit_ip, list(self.peers_ips)[attempt.retry_state.attempt_number - 2]

tests/unit/test_cluster.py

@@ -53,48 +53,48 @@ def setUp(self):
             False,
         )
 
-    def test_get_alternative_server_url(self):
+    def test_get_alternative_patroni_url(self):
         # Mock tenacity attempt.
         retry = tenacity.Retrying()
         retry_state = tenacity.RetryCallState(retry, None, None, None)
         attempt = tenacity.AttemptManager(retry_state)
 
         # Test the first URL that is returned (it should have the current unit IP).
-        url = self.patroni._get_alternative_server_url(attempt)
+        url = self.patroni._get_alternative_patroni_url(attempt)
         self.assertEqual(url, f"http://{self.patroni.unit_ip}:8008")
 
         # Test returning the other servers URLs.
         for attempt_number in range(
             attempt.retry_state.attempt_number + 1, len(self.peers_ips) + 2
         ):
             attempt.retry_state.attempt_number = attempt_number
-            url = self.patroni._get_alternative_server_url(attempt)
+            url = self.patroni._get_alternative_patroni_url(attempt)
             self.assertIn(url.split("http://")[1].split(":8008")[0], self.peers_ips)
 
     @mock.patch("requests.get", side_effect=mocked_requests_get)
-    @patch("charm.Patroni._get_alternative_server_url")
-    def test_get_member_ip(self, _get_alternative_server_url, _get):
+    @patch("charm.Patroni._get_alternative_patroni_url")
+    def test_get_member_ip(self, _get_alternative_patroni_url, _get):
         # Test error on trying to get the member IP.
-        _get_alternative_server_url.side_effect = "http://server2"
+        _get_alternative_patroni_url.side_effect = "http://server2"
         with self.assertRaises(tenacity.RetryError):
             self.patroni.get_member_ip(self.patroni.member_name)
 
-        # Test using an alternative server URL.
-        _get_alternative_server_url.side_effect = [
+        # Test using an alternative Patroni URL.
+        _get_alternative_patroni_url.side_effect = [
             "http://server3",
             "http://server2",
             "http://server1",
         ]
         ip = self.patroni.get_member_ip(self.patroni.member_name)
         self.assertEqual(ip, "1.1.1.1")
 
-        # Test using the current server URL.
-        _get_alternative_server_url.side_effect = ["http://server1"]
+        # Test using the current Patroni URL.
+        _get_alternative_patroni_url.side_effect = ["http://server1"]
         ip = self.patroni.get_member_ip(self.patroni.member_name)
         self.assertEqual(ip, "1.1.1.1")
 
         # Test when not having that specific member in the cluster.
-        _get_alternative_server_url.side_effect = ["http://server1"]
+        _get_alternative_patroni_url.side_effect = ["http://server1"]
         ip = self.patroni.get_member_ip("other-member-name")
         self.assertIsNone(ip)
 
@@ -109,29 +109,29 @@ def test_get_postgresql_version(self, _from_system):
         self.assertEqual(version, "12")
 
     @mock.patch("requests.get", side_effect=mocked_requests_get)
-    @patch("charm.Patroni._get_alternative_server_url")
-    def test_get_primary(self, _get_alternative_server_url, _get):
+    @patch("charm.Patroni._get_alternative_patroni_url")
+    def test_get_primary(self, _get_alternative_patroni_url, _get):
         # Test error on trying to get the member IP.
-        _get_alternative_server_url.side_effect = "http://server2"
+        _get_alternative_patroni_url.side_effect = "http://server2"
         with self.assertRaises(tenacity.RetryError):
             self.patroni.get_primary(self.patroni.member_name)
 
-        # Test using an alternative server URL.
-        _get_alternative_server_url.side_effect = [
+        # Test using an alternative Patroni URL.
+        _get_alternative_patroni_url.side_effect = [
             "http://server3",
             "http://server2",
             "http://server1",
         ]
         primary = self.patroni.get_primary()
         self.assertEqual(primary, "postgresql-0")
 
-        # Test using the current server URL.
-        _get_alternative_server_url.side_effect = ["http://server1"]
+        # Test using the current Patroni URL.
+        _get_alternative_patroni_url.side_effect = ["http://server1"]
         primary = self.patroni.get_primary()
         self.assertEqual(primary, "postgresql-0")
 
         # Test requesting the primary in the unit name pattern.
-        _get_alternative_server_url.side_effect = ["http://server1"]
+        _get_alternative_patroni_url.side_effect = ["http://server1"]
         primary = self.patroni.get_primary(unit_name_pattern=True)
         self.assertEqual(primary, "postgresql/0")