Allow running without zino.toml

changelog.d/458.fixed.md

@@ -0,0 +1 @@
+Actually allow zino to run without a zino.toml file, use the defaults instead.

src/zino/config/__init__.py

@@ -23,11 +23,14 @@ def read_configuration(config_file_name: str, poll_file_name: Optional[str] = No
     pydantic.ValidationError if values in it are invalid or the specified files
     don't exist
     """
-    with open(config_file_name, mode="rb") as cf:
-        try:
-            config_dict = load(cf)
-        except TOMLDecodeError:
-            raise InvalidConfigurationError
+    try:
+        with open(config_file_name, mode="rb") as cf:
+            try:
+                config_dict = load(cf)
+            except TOMLDecodeError:
+                raise InvalidConfigurationError
+    except FileNotFoundError:
+        config_dict = {}
 
     # Polldevs by command line argument will override config file entry
     if poll_file_name:
@@ -36,6 +39,6 @@ def read_configuration(config_file_name: str, poll_file_name: Optional[str] = No
         else:
             config_dict["polling"]["file"] = poll_file_name
 
-    config = Configuration.model_validate(obj=config_dict, strict=True)
+    config = Configuration().model_validate(obj=config_dict, strict=True)
 
     return config

src/zino/zino.py

@@ -79,12 +79,18 @@ def load_config(args: argparse.Namespace) -> Optional[state.Configuration]:
     Returns the configuration specified by the config file and None if no config file
     name was specified as argument and no default config file exists
     """
+    config_file = args.config_file or DEFAULT_CONFIG_FILE
     try:
-        return read_configuration(args.config_file or DEFAULT_CONFIG_FILE, args.polldevs)
+        with open(config_file, mode="rb"):
+            pass
     except OSError:
         if args.config_file:
             _log.fatal(f"No config file with the name {args.config_file} found.")
             sys.exit(1)
+        else:
+            _log.info("No config file found, using default configuration.")
+    try:
+        return read_configuration(config_file, args.polldevs)
     except InvalidConfigurationError:
         _log.fatal(f"Configuration file with the name {args.config_file or DEFAULT_CONFIG_FILE} is invalid TOML.")
         sys.exit(1)

tests/config_test.py

@@ -15,9 +15,9 @@ def test_pollfile_argument_overrides_pollfile_defined_in_file(self, zino_conf, p
         assert config
         assert config.polling.file == str(polldevs_conf_with_single_router)
 
-    def test_raises_error_on_file_not_found(self, tmp_path):
-        with pytest.raises(FileNotFoundError):
-            read_configuration(tmp_path / "non-existent-config.toml")
+    def test_succeeds_on_file_not_found(self, tmp_path):
+        config = read_configuration(tmp_path / "non-existent-config.toml")
+        assert config, "Default config not generated"
 
     def test_raises_error_on_invalid_toml_file(self, invalid_zino_conf):
         with pytest.raises(InvalidConfigurationError):

tests/zino_test.py

@@ -91,6 +91,12 @@ def test_when_args_specified_config_file_does_not_exist_then_load_config_should_
         zino.load_config(args)
 
 
+def test_when_no_config_file_specified_then_load_config_should_return_default_config(tmp_path):
+    args = Mock(config_file=tmp_path / "non_existent_file.toml")
+    config = zino.load_config(args)
+    assert config, "load_config did not return default config for missing config file"
+
+
 def test_when_logging_config_is_invalid_then_apply_logging_config_should_exit():
     with pytest.raises(SystemExit):
         zino.apply_logging_config({"loggers": {"zino": {"level": "invalid"}}})