Cleaner server shutdowns:

- Remove a workaround for Sanic server not always terminating cleanly
- Terminate worker threads before server stop
- Silent closing of watching WebSocket attempted to open while shutting down

cista/api.py

@@ -119,8 +119,12 @@ async def watch(req, ws):
         # Send updates
         while True:
             await ws.send(await q.get())
+    except RuntimeError as e:
+        if str(e) == "cannot schedule new futures after shutdown":
+            return  # Server shutting down, drop the WebSocket
+        raise
     finally:
-        del watching.pubsub[uuid]
+        watching.pubsub.pop(uuid, None)  # Remove whether it got added yet or not
 
 
 def subscribe(uuid, ws):

cista/app.py

@@ -43,14 +43,16 @@ async def main_start(app, loop):
     app.ctx.threadexec = ThreadPoolExecutor(
         max_workers=workers, thread_name_prefix="cista-ioworker"
     )
-    await watching.start(app, loop)
+    watching.start(app, loop)
 
 
-@app.after_server_stop
+# 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, loop):
     quit.set()
-    await watching.stop(app, loop)
+    watching.stop(app)
     app.ctx.threadexec.shutdown()
+    logger.debug("Cista worker threads all finished")
 
 
 @app.on_request

cista/preview.py

@@ -24,6 +24,17 @@ pillow_heif.register_heif_opener()
 
 bp = Blueprint("preview", url_prefix="/preview")
 
+# Map EXIF Orientation value to a corresponding PIL transpose
+EXIF_ORI = {
+    2: Image.Transpose.FLIP_LEFT_RIGHT,
+    3: Image.Transpose.ROTATE_180,
+    4: Image.Transpose.FLIP_TOP_BOTTOM,
+    5: Image.Transpose.TRANSPOSE,
+    6: Image.Transpose.ROTATE_270,
+    7: Image.Transpose.TRANSVERSE,
+    8: Image.Transpose.ROTATE_90,
+}
+
 
 @bp.get("/<path:path>")
 async def preview(req, path):
@@ -69,34 +80,35 @@ def dispatch(path, quality, maxsize, maxzoom):
 
 
 def process_image(path, *, maxsize, quality):
-    t_load_start = perf_counter()
+    t_load = perf_counter()
-    img = Image.open(path)
+    with Image.open(path) as img:
-    # Force decode to include I/O in load timing
+        # Force decode to include I/O in load timing
-    img.load()
+        img.load()
-    t_load_end = perf_counter()
+        t_proc = perf_counter()
-    # Resize
+        # Resize
-    orig_w, orig_h = img.size
+        w, h = img.size
-    t_proc_start = perf_counter()
+        img.thumbnail((min(w, maxsize), min(h, maxsize)))
-    img.thumbnail((min(orig_w, maxsize), min(orig_h, maxsize)))
+        # Transpose pixels according to EXIF Orientation
-    t_proc_end = perf_counter()
+        orientation = img.getexif().get(274, 1)
-    # Save as AVIF
+        if orientation in EXIF_ORI:
-    imgdata = io.BytesIO()
+            img = img.transpose(EXIF_ORI[orientation])
-    t_save_start = perf_counter()
+        # Save as AVIF
-    img.save(imgdata, format="avif", quality=quality, speed=10, max_threads=1)
+        imgdata = io.BytesIO()
-    t_save_end = perf_counter()
+        t_save = perf_counter()
+        img.save(imgdata, format="avif", quality=quality, speed=10, max_threads=1)
 
+    t_end = perf_counter()
     ret = imgdata.getvalue()
 
-    load_ms = (t_load_end - t_load_start) * 1000
+    load_ms = (t_proc - t_load) * 1000
-    proc_ms = (t_proc_end - t_proc_start) * 1000
+    proc_ms = (t_save - t_proc) * 1000
-    save_ms = (t_save_end - t_save_start) * 1000
+    save_ms = (t_end - t_save) * 1000
     logger.debug(
-        "Preview image %s: load=%.1fms process=%.1fms save=%.1fms out=%.1fKB",
+        "Preview image %s: load=%.1fms process=%.1fms save=%.1fms",
         path.name,
         load_ms,
         proc_ms,
         save_ms,
-        len(ret) / 1024,
     )
 
     return ret

cista/serve.py

@@ -1,6 +1,5 @@
 import os
 import re
-import signal
 from pathlib import Path
 
 from sanic import Sanic
@@ -12,14 +11,6 @@ def run(*, dev=False):
     """Run Sanic main process that spawns worker processes to serve HTTP requests."""
     from .app import app
 
-    # Set up immediate exit on Ctrl+C for faster termination
-    def signal_handler(signum, frame):
-        print("\nReceived interrupt signal, exiting immediately...")
-        os._exit(0)
-
-    signal.signal(signal.SIGINT, signal_handler)
-    signal.signal(signal.SIGTERM, signal_handler)
-
     url, opts = parse_listen(config.config.listen)
     # Silence Sanic's warning about running in production rather than debug
     os.environ["SANIC_IGNORE_PRODUCTION_WARNING"] = "1"

cista/watching.py

@@ -440,7 +440,7 @@ def watcher_poll(loop):
         quit.wait(0.1 + 8 * dur)
 
 
-async def start(app, loop):
+def start(app, loop):
     global rootpath
     config.load_config()
     rootpath = config.config.path
@@ -454,6 +454,6 @@ async def start(app, loop):
     app.ctx.watcher.start()
 
 
-async def stop(app, loop):
+def stop(app):
     quit.set()
     app.ctx.watcher.join()