chore: keep public-url config option for compatibility

config.yaml

@@ -36,3 +36,10 @@ options:
     type: string
     default: ''
     description: Static password for logging in without an external auth service
+  public-url:
+    type: string
+    default: ''
+    description: |
+      DEPRECATED - Please leave empty or use issuer-url instead. This configuration option will be removed soon.
+      It has been preserved to avoid breaking compatibility with existing deployments.
+      Publicly-accessible endpoint for cluster

src/charm.py

@@ -104,6 +104,19 @@ def _issuer_url(self) -> str:
         """Return issuer-url value if config option exists; otherwise default Dex's endpoint."""
         if issuer_url := self.model.config["issuer-url"]:
             return issuer_url
+        # TODO: remove this after the release of dex-auth 2.39
+        # This should not be supported anymore, but has been kept for compatibility
+        if public_url := self.model.config["public-url"]:
+            self.logger.warning(
+                "DEPRECATED: The public-url config option is deprecated"
+                "Please leave empty or use issuer-url;"
+                "otherwise this may cause unexpected behaviour."
+            )
+            # This will just cover cases like when the URL is my-dex.io:5557,
+            # not when it starts with a different protocol
+            if not public_url.startswith(("http://", "https://")):
+                public_url = f"http://{public_url}"
+            return f"{public_url}/dex"
         return (
             f"http://{self.model.app.name}.{self._namespace}.svc:{self.model.config['port']}/dex"
         )

tests/unit/test_charm.py

@@ -159,6 +159,7 @@ def test_config_changed(update, harness):
         "connectors": "connector01",
         "static-username": "new-user",
         "static-password": "new-pass",
+        "public-url": "",
     }
 
     harness.update_config(config_updates)
@@ -261,3 +262,46 @@ def test_grpc_relation_with_data_when_data_changes(
 
     # Change the port of the service and check the value changes
     assert provider_rel_data["issuer-url"] == harness.model.config["issuer-url"]
+
+
+@patch("charm.KubernetesServicePatch", lambda *_, **__: None)
+@pytest.mark.parametrize(
+    "issuer_url_config, default_value, expected_result",
+    (
+        (None, True, None),
+        ("http://my-dex.io:5557/dex", False, "http://my-dex.io:5557/dex"),
+    ),
+)
+def test_issuer_url_property_with_issuer_url_config(
+    issuer_url_config, default_value, expected_result, harness
+):
+    """Test the property returns as expected.
+
+
+    The first case assumes the issuer-url config option is not set, thus the default-value
+    of "http://dex-auth.<namespace>.svc:5556/dex" should be returned; the second case should return
+    the value set in the config option.
+    """
+    harness.set_leader(True)
+    harness.update_config({"issuer-url": issuer_url_config})
+    harness.begin()
+
+    if default_value:
+        expected_result = f"http://{harness.model.app.name}.{harness.model.name}.svc:5556/dex"
+    assert harness.charm._issuer_url == expected_result
+
+
+@patch("charm.KubernetesServicePatch", lambda *_, **__: None)
+@pytest.mark.parametrize(
+    "public_url_config, expected_result",
+    (
+        ("http://my-dex.io:5557", "http://my-dex.io:5557/dex"),
+        ("my-dex.io:5557", "http://my-dex.io:5557/dex"),
+    ),
+)
+def test_issuer_url_property_with_public_url_config(public_url_config, expected_result, harness):
+    """Test the property returns as expected."""
+    harness.set_leader(True)
+    harness.update_config({"public-url": public_url_config})
+    harness.begin()
+    assert harness.charm._issuer_url == expected_result