Fixes on server startup and shutdown with Sanic internals. Parallel shutdown tasks as non-blocking async tasks to avoid blocking the event loop and causing a warning of that.

cista/app.py

@@ -148,12 +148,16 @@ async def main_after_start(app):
 # Sanic sometimes fails to execute after_server_stop, so we do it before instead (potentially interrupting handlers)
 @app.before_server_stop
 async def main_stop(app):
-    watching.stop(app)
-    await onlyoffice.close_oo_client()
-    await shutdown_preview_workers()
-    app.ctx.threadexec.shutdown()
-    app.ctx.zipexec.shutdown(cancel_futures=True)
-    await sso.close_client()
+    async with asyncio.TaskGroup() as tg:
+        tg.create_task(asyncio.to_thread(watching.stop, app))
+        tg.create_task(onlyoffice.close_oo_client())
+        tg.create_task(shutdown_preview_workers())
+        tg.create_task(sso.close_client())
+
+    async with asyncio.TaskGroup() as tg:
+        tg.create_task(asyncio.to_thread(app.ctx.threadexec.shutdown))
+        tg.create_task(asyncio.to_thread(app.ctx.zipexec.shutdown, cancel_futures=True))
+
     logger.debug("Cista worker threads all finished")
 
 

cista/sanic_logging.py

@@ -1,6 +1,7 @@
 """Custom access logging middleware for Sanic."""
 
 import logging
+import os
 import sys
 import unicodedata
 from ipaddress import IPv6Address
@@ -9,6 +10,40 @@ from sanic.log import LOGGING_CONFIG_DEFAULTS
 
 logger = logging.getLogger("cista.access")
 
+
+class ReentrantSafeStreamHandler(logging.StreamHandler):
+    """Stream handler that degrades gracefully on signal-time reentrant writes.
+
+    Python's buffered text streams are not reentrant. If a signal handler logs
+    while another log write is in progress, StreamHandler.emit can raise:
+    RuntimeError("reentrant call inside <_io.BufferedWriter ...>")
+
+    Instead of letting logging emit a long "--- Logging error ---" traceback,
+    we fall back to a best-effort os.write to the same file descriptor.
+    """
+
+    def emit(self, record: logging.LogRecord) -> None:
+        msg = ""
+        try:
+            msg = self.format(record)
+            stream = self.stream
+            stream.write(msg + self.terminator)
+            self.flush()
+        except RuntimeError as exc:
+            if "reentrant call inside" not in str(exc):
+                self.handleError(record)
+                return
+            stream = self.stream
+            fd = stream.fileno()
+            encoding = getattr(stream, "encoding", None) or "utf-8"
+            data = (msg + self.terminator).encode(encoding, errors="replace")
+            os.write(fd, data)
+        except RecursionError:
+            raise
+        except Exception:
+            self.handleError(record)
+
+
 _RESET = "\033[0m"
 _STATUS_INFO = "\033[32m"  # 1xx (green)
 _STATUS_OK = "\033[1;92m"  # 2xx (bright green)
@@ -236,7 +271,7 @@ def log_ws_close(
 
 def configure_access_logging() -> None:
     """Configure the cista.access logger to output to stderr."""
-    handler = logging.StreamHandler(sys.stderr)
+    handler = ReentrantSafeStreamHandler(sys.stderr)
     handler.setFormatter(logging.Formatter("%(message)s"))
     logger.addHandler(handler)
     logger.setLevel(logging.INFO)
@@ -271,6 +306,10 @@ def configure_main_logging() -> None:
     Patches LOGGING_CONFIG_DEFAULTS so the formatter survives every dictConfig
     call Sanic makes during serve_single() / serve().
     """
+    for handler_name in ("console", "error_console", "access_console"):
+        LOGGING_CONFIG_DEFAULTS["handlers"][handler_name]["class"] = (
+            "cista.sanic_logging.ReentrantSafeStreamHandler"
+        )
     LOGGING_CONFIG_DEFAULTS["formatters"]["generic"] = {
         "class": "cista.sanic_logging._EmojiFormatter",
     }

cista/serve.py

@@ -4,11 +4,17 @@ from pathlib import Path
 
 from fastapi_vue.hostutil import parse_endpoint
 from sanic import Sanic
+from sanic.worker.loader import AppLoader
 
 from cista import config, server80
 from cista.app import app
 
 
+def load_app() -> Sanic:
+    """Return the app instance for spawned Sanic worker/reloader processes."""
+    return app
+
+
 def run(*, dev=False):
     """Run Sanic main process that spawns worker processes to serve HTTP requests."""
     _url, opts = parse_listen(config.config.listen)
@@ -29,7 +35,7 @@ def run(*, dev=False):
         access_log=False,
     )  # type: ignore[call-arg]
     if dev:
-        Sanic.serve()
+        Sanic.serve(app_loader=AppLoader(factory=load_app))
     else:
         Sanic.serve_single()
 

cista/watching.py

@@ -55,6 +55,10 @@ class FormatUpdateLoopError(RuntimeError):
     pass
 
 
+class _WatcherStoppingError(Exception):
+    """Internal control-flow exception for quick watcher shutdown."""
+
+
 class State:
     def __init__(self):
         self.lock = threading.RLock()
@@ -215,7 +219,7 @@ def walk(rel: PurePosixPath, stat: stat_result | None = None) -> list[FileEntry]
         li = []
         for f in path.iterdir():
             if stop_event.is_set():
-                raise SystemExit("quit")
+                raise _WatcherStoppingError
             if f.name.startswith("."):
                 continue  # No dotfiles
             with suppress(FileNotFoundError):
@@ -227,7 +231,11 @@ def walk(rel: PurePosixPath, stat: stat_result | None = None) -> list[FileEntry]
                 li.append((int(isfile), f.name, s))
         # Build the tree as a list of FileEntries
         for [_, name, s] in humansorted(li):
+            if stop_event.is_set():
+                raise _WatcherStoppingError
             sub = walk(rel / name, stat=s)
+            if not sub:
+                continue
             child = sub[0]
             entry = FileEntry(
                 level=entry.level,
@@ -679,7 +687,10 @@ def watcher(loop):
             inotify_tree = inotify.adapters.InotifyTree(rootpath.as_posix())
 
         # Initialize the tree from filesystem
-        update_root(loop)
+        try:
+            update_root(loop)
+        except _WatcherStoppingError:
+            return
         path_index = PathIndex(state.root[:])
 
         trefresh = time.monotonic() + 300.0
@@ -763,7 +774,10 @@ def watcher(loop):
                 # Process each collapsed path
                 new_root = path_index.root
                 for path in collapsed:
-                    new_entries = walk(path)
+                    try:
+                        new_entries = walk(path)
+                    except _WatcherStoppingError:
+                        return
                     new_root = path_index.apply_update(path, new_entries)
 
                 # Broadcast if changed
@@ -782,6 +796,8 @@ def watcher(loop):
                             with state.lock:
                                 broadcast(update_msg, loop)
                                 state.root = fresh
+                        except _WatcherStoppingError:
+                            return
                         except Exception:
                             logger.exception("Fallback failed; sending full root")
                             with state.lock:
@@ -870,6 +886,7 @@ def start(app):
     global rootpath
     config.load_config()
     rootpath = config.config.path
+    stop_event.clear()
     app.ctx.watcher = threading.Thread(
         target=watcher,
         args=[app.loop],