fix: rotate log files instead of growing without bound (#885) (#932)

proxy/tg_ws_proxy.py

@@ -568,8 +568,9 @@ def main():
                     help='Log to file with rotation (default: stderr only)')
     ap.add_argument('--log-max-mb', type=float, default=5, metavar='MB',
                     help='Max log file size in MB before rotation (default 5)')
-    ap.add_argument('--log-backups', type=int, default=0, metavar='N',
-                    help='Number of rotated log files to keep (default 0)')
+    ap.add_argument('--log-backups', type=int, default=1, metavar='N',
+                    help='Number of rotated log files to keep (min 1; '
+                         'rotation needs at least one backup to bound size)')
     ap.add_argument('--buf-kb', type=int, default=256, metavar='KB',
                     help='Socket send/recv buffer size in KB (default 256)')
     ap.add_argument('--pool-size', type=int, default=4, metavar='N',
@@ -640,11 +641,11 @@ def main():
     root.addHandler(console)
 
     if args.log_file:
-        fh = logging.handlers.RotatingFileHandler(
+        from utils.logging_setup import build_log_handler
+        fh = build_log_handler(
             args.log_file,
-            maxBytes=max(32 * 1024, int(args.log_max_mb * 1024 * 1024)),
-            backupCount=max(0, args.log_backups),
-            encoding='utf-8',
+            log_max_mb=args.log_max_mb,
+            backups=args.log_backups,
         )
         fh.setFormatter(log_fmt)
         root.addHandler(fh)

utils/logging_setup.py

@@ -0,0 +1,39 @@
+"""Shared construction of the rotating log file handler.
+
+Centralizes the rotation invariant so both the tray and the CLI log paths
+behave identically and the file can never grow without bound (issue #885).
+
+A ``RotatingFileHandler`` only rotates when ``backupCount >= 1``: CPython's
+``doRollover`` skips the entire rotation block when ``backupCount == 0``, so
+``maxBytes`` is silently ignored and the active file grows forever. We force
+at least one backup here regardless of caller input.
+"""
+
+from __future__ import annotations
+
+import logging.handlers
+
+
+_MIN_BYTES = 32 * 1024
+_MIN_BACKUPS = 1
+
+
+def build_log_handler(
+    path: str,
+    log_max_mb: float = 5,
+    backups: int = 1,
+) -> logging.handlers.RotatingFileHandler:
+    """Create a RotatingFileHandler that actually rotates.
+
+    ``backups`` is clamped to at least 1 so rotation is always active, and
+    ``maxBytes`` keeps a small floor so a misconfigured tiny size can't cause
+    rotation on every line.
+    """
+    max_bytes = max(_MIN_BYTES, int(log_max_mb * 1024 * 1024))
+    backup_count = max(_MIN_BACKUPS, int(backups))
+    return logging.handlers.RotatingFileHandler(
+        path,
+        maxBytes=max_bytes,
+        backupCount=backup_count,
+        encoding="utf-8",
+    )

utils/tray_common.py

@@ -17,6 +17,7 @@ import psutil
 from proxy import __version__, get_link_host, parse_dc_ip_list, proxy_config, coerce_domain_list
 from proxy.tg_ws_proxy import _run
 from utils.default_config import default_tray_config
+from utils.logging_setup import build_log_handler
 
 log = logging.getLogger("tg-ws-tray")
 
@@ -155,12 +156,7 @@ def setup_logging(verbose: bool = False, log_max_mb: float = 5) -> None:
     root.setLevel(level)
     logging.getLogger('asyncio').setLevel(logging.WARNING)
 
-    fh = logging.handlers.RotatingFileHandler(
-        str(LOG_FILE),
-        maxBytes=max(32 * 1024, int(log_max_mb * 1024 * 1024)),
-        backupCount=0,
-        encoding="utf-8",
-    )
+    fh = build_log_handler(str(LOG_FILE), log_max_mb=log_max_mb, backups=1)
     fh.setLevel(logging.DEBUG)
     fh.setFormatter(logging.Formatter(_LOG_FMT_FILE, datefmt="%Y-%m-%d %H:%M:%S"))
     root.addHandler(fh)