change type of Config value to str

lib/charms/operator_libs_linux/v0/sysctl.py

@@ -14,6 +14,18 @@
 
 """Handler for the sysctl config.
 
+This library allows your charm to create and update sysctl config options to the machine.
+
+Validation and merge capabilities are added, for situations where more than one application
+are setting values. The following files can be created:
+
+- /etc/sysctl.d/90-juju-<app-name>
+    Requirements from one application requesting to update the values.
+
+- /etc/sysctl.d/95-juju-sysctl.conf
+    Merged file resulting from all other `90-juju-*` application files.
+
+
 A charm using the sysctl lib will need a data structure like the following:
 ```yaml
 vm.swappiness:
@@ -56,6 +68,7 @@ def _on_install(self, _):
 
     def _on_remove(self, _):
         self.sysctl.remove()
+```
 """
 
 import logging
@@ -135,7 +148,7 @@ def __iter__(self):
         """Iterate over config."""
         return iter(self._data)
 
-    def __getitem__(self, key: str) -> int:
+    def __getitem__(self, key: str) -> str:
         """Get value for key form config."""
         return self._data[key]
 
@@ -155,8 +168,7 @@ def update(self, config: Dict[str, dict]) -> None:
         """
         self._parse_config(config)
 
-        # NOTE: case where own charm calls update() more than once. Remove first so
-        # we don't get validation errors.
+        # NOTE: case where own charm calls update() more than once.
         if self.charm_filepath.exists():
             self._merge(add_own_charm=False)
 
@@ -237,11 +249,11 @@ def _apply(self) -> None:
             logger.error(msg)
             raise SysctlPermissionError(msg)
 
-    def _create_snapshot(self) -> Dict[str, int]:
+    def _create_snapshot(self) -> Dict[str, str]:
         """Create a snaphot of config options that are going to be set."""
         return {key: int(self._sysctl([key, "-n"])[0]) for key in self._desired_config.keys()}
 
-    def _restore_snapshot(self, snapshot: Dict[str, int]) -> None:
+    def _restore_snapshot(self, snapshot: Dict[str, str]) -> None:
         """Restore a snapshot to the machine."""
         values = [f"{key}={value}" for key, value in snapshot.items()]
         self._sysctl(values)
@@ -261,10 +273,10 @@ def _parse_config(self, config: Dict[str, dict]) -> None:
         """Parse a config passed to the lib."""
         result = {}
         for key, value in config.items():
-            result[key] = int(value["value"])
-        self._desired_config: Dict[str, int] = result
+            result[key] = value["value"]
+        self._desired_config: Dict[str, str] = result
 
-    def _load_data(self) -> Dict[str, int]:
+    def _load_data(self) -> Dict[str, str]:
         """Get merged config."""
         config = {}
         if not SYSCTL_FILENAME.exists():
@@ -276,10 +288,10 @@ def _load_data(self) -> Dict[str, int]:
 
         return config
 
-    def _parse_line(self, line: str) -> Dict[str, int]:
+    def _parse_line(self, line: str) -> Dict[str, str]:
         """Parse a line from juju-sysctl.conf file."""
         if line.startswith("#") or line == "\n":
             return {}
 
         param, value = line.split("=")
-        return {param.strip(): int(value.strip())}
+        return {param.strip(): value.strip()}

tests/unit/test_sysctl.py

@@ -125,7 +125,7 @@ def test_load_data(self, mock_file, mock_exist):
 
         mock_exist.assert_called()
         mock_file.assert_called_with(Path("/etc/sysctl.d/95-juju-sysctl.conf"), "r")
-        assert config._data == {"vm.swappiness": 0, "vm.max_map_count": 262144}
+        assert config._data == {"vm.swappiness": "0", "vm.max_map_count": "262144"}
 
     @patch("pathlib.Path.exists")
     def test_load_data_no_path(self, mock_exist):
@@ -314,7 +314,7 @@ def test_parse_config(self, _):
 
         config._parse_config({"key1": {"value": "10"}, "key2": {"value": "20"}})
 
-        self.assertEqual(config._desired_config, {"key1": 10, "key2": 20})
+        self.assertEqual(config._desired_config, {"key1": "10", "key2": "20"})
 
     @patch("charms.operator_libs_linux.v0.sysctl.Config._load_data")
     def test_class_methods(self, mock_load):