Watching cleanup

cista/watching.py

@@ -1,11 +1,12 @@
 import asyncio
 import shutil
-import stat
 import sys
 import threading
 import time
+from contextlib import suppress
 from os import stat_result
 from pathlib import Path, PurePosixPath
+from stat import S_ISDIR
 
 import msgspec
 from natsort import humansorted, natsort_keygen, ns
@@ -115,95 +116,15 @@ state = State()
 rootpath: Path = None  # type: ignore
 quit = threading.Event()
 
-modified_flags = (
+## Filesystem scanning
-    "IN_CREATE",
-    "IN_DELETE",
-    "IN_DELETE_SELF",
-    "IN_MODIFY",
-    "IN_MOVE_SELF",
-    "IN_MOVED_FROM",
-    "IN_MOVED_TO",
-)
 
 
-def watcher_thread(loop):
+def walk(rel: PurePosixPath, stat: stat_result | None = None) -> list[FileEntry]:
-    global rootpath
-    import inotify.adapters
-
-    while not quit.is_set():
-        rootpath = config.config.path
-        i = inotify.adapters.InotifyTree(rootpath.as_posix())
-        # Initialize the tree from filesystem
-        new = walk()
-        with state.lock:
-            old = state.root
-            if old != new:
-                state.root = new
-                broadcast(format_update(old, new), loop)
-
-        # The watching is not entirely reliable, so do a full refresh every 30 seconds
-        refreshdl = time.monotonic() + 30.0
-
-        for event in i.event_gen():
-            if quit.is_set():
-                return
-            # Disk usage update
-            du = shutil.disk_usage(rootpath)
-            space = Space(*du, storage=state.root[0].size)
-            if space != state.space:
-                state.space = space
-                broadcast(format_space(space), loop)
-                break
-            # Do a full refresh?
-            if time.monotonic() > refreshdl:
-                break
-            if event is None:
-                continue
-            _, flags, path, filename = event
-            if not any(f in modified_flags for f in flags):
-                continue
-            # Update modified path
-            path = PurePosixPath(path) / filename
-            try:
-                update(path.relative_to(rootpath), loop)
-            except Exception as e:
-                print("Watching error", e, path, rootpath)
-                raise
-        i = None  # Free the inotify object
-
-
-def watcher_thread_poll(loop):
-    global rootpath
-
-    while not quit.is_set():
-        rootpath = config.config.path
-        new = walk()
-        with state.lock:
-            old = state.root
-            if old != new:
-                state.root = new
-                broadcast(format_update(old, new), loop)
-
-        # Disk usage update
-        du = shutil.disk_usage(rootpath)
-        space = Space(*du, storage=state.root[0].size)
-        if space != state.space:
-            state.space = space
-            broadcast(format_space(space), loop)
-
-        quit.wait(2.0)
-
-
-def walk(rel=PurePosixPath()) -> list[FileEntry]:  # noqa: B008
     path = rootpath / rel
+    ret = []
     try:
-        st = path.stat()
+        st = stat or path.stat()
-    except OSError:
+        isfile = not S_ISDIR(st.st_mode)
-        return []
-    return _walk(rel, int(not stat.S_ISDIR(st.st_mode)), st)
-
-
-def _walk(rel: PurePosixPath, isfile: int, st: stat_result) -> list[FileEntry]:
         entry = FileEntry(
             level=len(rel.parts),
             name=rel.name,
@@ -214,36 +135,43 @@ def _walk(rel: PurePosixPath, isfile: int, st: stat_result) -> list[FileEntry]:
         )
         if isfile:
             return [entry]
+        # Walk all entries of the directory
         ret = [entry]
-    path = rootpath / rel
-    try:
         li = []
         for f in path.iterdir():
             if quit.is_set():
                 raise SystemExit("quit")
             if f.name.startswith("."):
                 continue  # No dotfiles
+            with suppress(FileNotFoundError):
                 s = f.stat()
-            li.append((int(not stat.S_ISDIR(s.st_mode)), f.name, s))
+                li.append((int(not S_ISDIR(s.st_mode)), f.name, s))
-        for [isfile, name, s] in humansorted(li):
+        # Build the tree as a list of FileEntries
-            if quit.is_set():
+        for [_, name, s] in humansorted(li):
-                raise SystemExit("quit")
+            sub = walk(rel / name, stat=s)
-            subtree = _walk(rel / name, isfile, s)
+            ret.extend(sub)
-            child = subtree[0]
+            child = sub[0]
             entry.mtime = max(entry.mtime, child.mtime)
             entry.size += child.size
-            ret.extend(subtree)
     except FileNotFoundError:
         pass  # Things may be rapidly in motion
-    except OSError as e:
+    except OSError:
-        print("OS error walking path", path, e)
+        logger.error(f"Watching {path=}: {e!r}")
     return ret
 
 
-def update(relpath: PurePosixPath, loop):
+def update_root(loop):
-    """Called by inotify updates, check the filesystem and broadcast any changes."""
+    """Full filesystem scan"""
-    if rootpath is None or relpath is None:
+    new = walk(PurePosixPath())
-        print("ERROR", rootpath, relpath)
+    with state.lock:
+        old = state.root
+        if old != new:
+            state.root = new
+            broadcast(format_update(old, new), loop)
+
+
+def update_path(relpath: PurePosixPath, loop):
+    """Called on FS updates, check the filesystem and broadcast any changes."""
     new = walk(relpath)
     with state.lock:
         old = state[relpath]
@@ -257,6 +185,22 @@ def update(relpath: PurePosixPath, loop):
         broadcast(format_update(old, state.root), loop)
 
 
+def update_space(loop):
+    """Called periodically to update the disk usage."""
+    du = shutil.disk_usage(rootpath)
+    space = Space(*du, storage=state.root[0].size)
+    # Update only on difference above 1 MB
+    tol = 10**6
+    old = msgspec.structs.astuple(state.space)
+    new = msgspec.structs.astuple(space)
+    if any(abs(o - n) > tol for o, n in zip(old, new, strict=True)):
+        state.space = space
+        broadcast(format_space(space), loop)
+
+
+## Messaging
+
+
 def format_update(old, new):
     # Make keep/del/insert diff until one of the lists ends
     oidx, nidx = 0, 0
@@ -320,18 +264,70 @@ async def abroadcast(msg):
         logger.exception("Broadcast error")
 
 
+## Watcher thread
+
+
+def watcher_inotify(loop):
+    """Inotify watcher thread (Linux only)"""
+    import inotify.adapters
+
+    modified_flags = (
+        "IN_CREATE",
+        "IN_DELETE",
+        "IN_DELETE_SELF",
+        "IN_MODIFY",
+        "IN_MOVE_SELF",
+        "IN_MOVED_FROM",
+        "IN_MOVED_TO",
+    )
+    while not quit.is_set():
+        i = inotify.adapters.InotifyTree(rootpath.as_posix())
+        # Initialize the tree from filesystem
+        update_root(loop)
+        trefresh = time.monotonic() + 30.0
+        tspace = time.monotonic() + 5.0
+        # Watch for changes (frequent wakeups needed for quiting)
+        for event in i.event_gen(timeout_s=0.1):
+            if quit.is_set():
+                break
+            t = time.monotonic()
+            # The watching is not entirely reliable, so do a full refresh every 30 seconds
+            if t >= trefresh:
+                break
+            # Disk usage update
+            if t >= tspace:
+                tspace = time.monotonic() + 5.0
+                update_space(loop)
+            # Inotify event, update the tree
+            if event and any(f in modified_flags for f in event[1]):
+                # Update modified path
+                update_path(PurePosixPath(event[2]) / event[3], loop)
+
+        del i  # Free the inotify object
+
+
+def watcher_poll(loop):
+    """Polling version of the watcher thread."""
+    while not quit.is_set():
+        update_root(loop)
+        update_space(loop)
+        quit.wait(2.0)
+
+
 async def start(app, loop):
+    global rootpath
     config.load_config()
+    rootpath = config.config.path
     use_inotify = sys.platform == "linux"
     app.ctx.watcher = threading.Thread(
-        target=watcher_thread if use_inotify else watcher_thread_poll,
+        target=watcher_inotify if use_inotify else watcher_poll,
         args=[loop],
-        name="watcher",
+        # Descriptive name for system monitoring
+        name=f"cista-watcher {rootpath}",
     )
     app.ctx.watcher.start()
 
 
 async def stop(app, loop):
-    global quit
     quit.set()
     app.ctx.watcher.join()