fix: key error on charm state upgrade

canonical · Jun 6, 2024 · 47362b8 · 47362b8
1 parent 379094b
commit 47362b8
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Showing 2 changed files with 65 additions and 16 deletions.
diff --git a/src/charm_state.py b/src/charm_state.py
@@ -846,23 +846,37 @@ def _check_immutable_config_change(
         prev_state = json.loads(json_data)
         logger.info("Previous charm state: %s", prev_state)
 
-        if prev_state["runner_config"]["runner_storage"] != runner_storage:
-            logger.error(
-                "Storage option changed from %s to %s, blocking the charm",
-                prev_state["runner_config"]["runner_storage"],
-                runner_storage,
-            )
-            raise ImmutableConfigChangedError(
-                msg="runner-storage config cannot be changed after deployment, redeploy if needed"
-            )
-        if prev_state["runner_config"]["base_image"] != base_image.value:
-            logger.error(
-                "Base image option changed from %s to %s, blocking the charm",
-                prev_state["runner_config"]["base_image"],
-                runner_storage,
+        try:
+            if prev_state["runner_config"]["runner_storage"] != runner_storage:
+                logger.error(
+                    "Storage option changed from %s to %s, blocking the charm",
+                    prev_state["runner_config"]["runner_storage"],
+                    runner_storage,
+                )
+                raise ImmutableConfigChangedError(
+                    msg=(
+                        "runner-storage config cannot be changed after deployment, "
+                        "redeploy if needed"
+                    )
+                )
+        except KeyError as exc:
+            logger.warning(
+                "Key %s not found, this will be updated to current config.", exc.args[0]
             )
-            raise ImmutableConfigChangedError(
-                msg="base-image config cannot be changed after deployment, redeploy if needed"
+
+        try:
+            if prev_state["runner_config"]["base_image"] != base_image.value:
+                logger.error(
+                    "Base image option changed from %s to %s, blocking the charm",
+                    prev_state["runner_config"]["base_image"],
+                    runner_storage,
+                )
+                raise ImmutableConfigChangedError(
+                    msg="base-image config cannot be changed after deployment, redeploy if needed"
+                )
+        except KeyError as exc:
+            logger.warning(
+                "Key %s not found, this will be updated to current config.", exc.args[0]
             )
 
     @classmethod

diff --git a/tests/unit/test_charm_state.py b/tests/unit/test_charm_state.py
@@ -929,6 +929,41 @@ def mock_charm_state_data():
     }
 
 
+@pytest.mark.parametrize(
+    "immutable_config",
+    [
+        pytest.param("runner_storage", id="Runner storage"),
+        pytest.param("base_image", id="Base image"),
+    ],
+)
+def test_check_immutable_config_key_error(
+    mock_charm_state_path: Path,
+    mock_charm_state_data: dict[str, typing.Any],
+    immutable_config: str,
+    monkeypatch: pytest.MonkeyPatch,
+    caplog: pytest.LogCaptureFixture,
+):
+    """
+    arrange: Mock CHARM_STATE_PATH and read_text method to return previous state with same config.
+    act: Call _check_immutable_config_change method.
+    assert: None is returned.
+    """
+    mock_charm_state_data["runner_config"].pop(immutable_config)
+    monkeypatch.setattr(charm_state, "CHARM_STATE_PATH", mock_charm_state_path)
+    monkeypatch.setattr(
+        charm_state.CHARM_STATE_PATH,
+        "read_text",
+        MagicMock(return_value=json.dumps(mock_charm_state_data)),
+    )
+    state = CharmState(**mock_charm_state_data)
+
+    assert state._check_immutable_config_change(RunnerStorage.MEMORY, BaseImage.JAMMY) is None
+    assert any(
+        f"Key {immutable_config} not found, this will be updated to current config." in message
+        for message in caplog.messages
+    )
+
+
 def test_check_immutable_config_change_no_previous_state(
     mock_charm_state_path: Path, mock_charm_state_data: dict, monkeypatch: pytest.MonkeyPatch
 ):