fix(config): fail fast on malformed or missing config files (#164)

VERSION

@@ -1 +1 @@
-1.8.22
+1.8.23

src/torchlight/Config.py

@@ -1,11 +1,14 @@
 import json
 import logging
 import os
-import sys
 from collections import OrderedDict
 from typing import Any
 
 
+class ConfigError(Exception):
+    """A config file is missing, unreadable or contains invalid JSON."""
+
+
 class ConfigFile:
     """Resolves a config file path under the config folder and parses it as JSON."""
 
@@ -20,10 +23,19 @@ def __init__(
         self.config_filepath = os.path.abspath(os.path.join(config_folder, config_filename))
 
     def load_json(self, *, ordered: bool = False) -> Any:
-        with open(self.config_filepath) as fp:
-            if ordered:
-                return json.load(fp, object_pairs_hook=OrderedDict)
-            return json.load(fp)
+        try:
+            with open(self.config_filepath) as fp:
+                if ordered:
+                    return json.load(fp, object_pairs_hook=OrderedDict)
+                return json.load(fp)
+        except FileNotFoundError as e:
+            raise ConfigError(f"{self.config_filepath}: config file not found") from e
+        except OSError as e:
+            raise ConfigError(f"{self.config_filepath}: cannot read config file ({e.strerror or e})") from e
+        except json.JSONDecodeError as e:
+            raise ConfigError(
+                f"{self.config_filepath}: invalid JSON on line {e.lineno}, column {e.colno} ({e.msg})"
+            ) from e
 
 
 class Config(ConfigFile):
@@ -35,13 +47,8 @@ def __init__(
         super().__init__(config_folder, config_filename)
         self.config: dict[str, Any] = {}
 
-    def load(self) -> int:
-        try:
-            self.config = self.load_json()
-        except ValueError as e:
-            self.logger.error(sys._getframe().f_code.co_name + " " + str(e))
-            return 1
-        return 0
+    def load(self) -> None:
+        self.config = self.load_json()
 
     def __getitem__(self, key: str) -> Any:
         if key in self.config:

src/torchlight/Sourcemod.py

@@ -1,5 +1,4 @@
 import copy
-import sys
 from collections import OrderedDict
 from dataclasses import dataclass
 
@@ -34,12 +33,8 @@ def __init__(
         self.sm_flags: OrderedDict = OrderedDict()
         self.sm_groups: list[SourcemodGroup] = []
 
-    def Load(self) -> int:
-        try:
-            self.sm_flags = self.load_json(ordered=True)
-        except ValueError as e:
-            self.logger.error(sys._getframe().f_code.co_name + " " + str(e))
-            return 1
+    def Load(self) -> None:
+        self.sm_flags = self.load_json(ordered=True)
         self.sm_groups.clear()
         for sm_group in self.config["SourcemodGroups"]:
             self.sm_groups.append(
@@ -49,7 +44,6 @@ def Load(self) -> int:
                     flags=sm_group["flags"],
                 )
             )
-        return 0
 
     def flagbits_to_flags(self, *, flagbits: int) -> list[str]:
         flags: list[str] = []

src/torchlight/cli.py

@@ -6,7 +6,7 @@
 
 import click
 
-from torchlight.Config import Config
+from torchlight.Config import Config, ConfigError
 from torchlight.PlayerManager import PlayerManager
 from torchlight.SourceRCONServer import SourceRCONServer
 from torchlight.TorchlightHandler import TorchlightHandler
@@ -30,7 +30,13 @@ def graceful_shutdown(signal: int, frame: FrameType | None) -> None:
 @click.version_option()
 def cli(config_folder: str) -> None:
     config = Config(config_folder)
-    config.load()
+
+    # A malformed or missing config file aborts startup with the offending path and
+    # parse error rather than silently starting with an empty config (see issue #164).
+    try:
+        config.load()
+    except ConfigError as e:
+        raise click.ClickException(str(e)) from e
 
     logging.basicConfig(
         level=logging.getLevelName(config["Logging"]["level"]),
@@ -44,7 +50,10 @@ def cli(config_folder: str) -> None:
     event_loop = asyncio.get_event_loop()
 
     global torchlight_handler
-    torchlight_handler = TorchlightHandler(event_loop, config)
+    try:
+        torchlight_handler = TorchlightHandler(event_loop, config)
+    except ConfigError as e:
+        raise click.ClickException(str(e)) from e
 
     # Handles new connections on 0.0.0.0:27015
     rcon_server = SourceRCONServer(