Only support file based locking

config

@@ -117,11 +117,6 @@
 # Delete sync token that are older (seconds)
 #max_sync_token_age = 2592000
 
-# Close the lock file when no more clients are waiting.
-# This option is not very useful in general, but on Windows files that are
-# opened cannot be deleted.
-#filesystem_close_lock_file = False
-
 # Command that is run after changes to storage
 # Example: ([ -d .git ] || git init) && git add -A && (git diff --cached --quiet || git commit -m "Changes by "%(user)s)
 #hook =

radicale/config.py

@@ -173,14 +173,6 @@ INITIAL_CONFIG = OrderedDict([
             "value": "True",
             "help": "sync all changes to filesystem during requests",
             "type": bool}),
-        ("filesystem_locking", {
-            "value": "True",
-            "help": "lock the storage while accessing it",
-            "type": bool}),
-        ("filesystem_close_lock_file", {
-            "value": "False",
-            "help": "close the lock file when no more clients are waiting",
-            "type": bool}),
         ("hook", {
             "value": "",
             "help": "command that is run after changes to storage",

radicale/storage.py

@@ -805,16 +805,8 @@ class Collection(BaseCollection):
         folder = os.path.expanduser(cls.configuration.get(
             "storage", "filesystem_folder"))
         cls._makedirs_synced(folder)
-        lock_path = None
-        if cls.configuration.getboolean("storage", "filesystem_locking"):
-            lock_path = os.path.join(folder, ".Radicale.lock")
-        close_lock_file = cls.configuration.getboolean(
-            "storage", "filesystem_close_lock_file")
-        cls._lock = FileBackedRwLock(lock_path, close_lock_file)
-
-        # init cache lock
-        cls._cache_locks = {}
-        cls._cache_locks_lock = threading.Lock()
+        lock_path = os.path.join(folder, ".Radicale.lock")
+        cls._lock = FileBackedRwLock(lock_path)
 
     def __init__(self, path, principal=None, folder=None,
                  filesystem_path=None):
@@ -1382,36 +1374,15 @@ class Collection(BaseCollection):
             pass
         return content
 
-    @contextmanager
     def _acquire_cache_lock(self, ns=""):
-        if "/" in ns:
-            raise ValueError("ns must not include '/'")
-        with contextlib.ExitStack() as lock_stack:
-            with contextlib.ExitStack() as locks_lock_stack:
-                locks_lock_stack.enter_context(self._cache_locks_lock)
-                lock_id = ns + "/" + self.path
-                lock = self._cache_locks.get(lock_id)
-                if not lock:
-                    cache_folder = os.path.join(self._filesystem_path,
-                                                ".Radicale.cache")
-                    self._makedirs_synced(cache_folder)
-                    lock_path = None
-                    if self.configuration.getboolean(
-                            "storage", "filesystem_locking"):
-                        lock_path = os.path.join(
-                            cache_folder,
-                            ".Radicale.lock" + (".%s" % ns if ns else ""))
-                    lock = FileBackedRwLock(lock_path)
-                    self._cache_locks[lock_id] = lock
-                lock_stack.enter_context(lock.acquire_lock(
-                    "w", lambda: locks_lock_stack.pop_all().close()))
-            try:
-                yield
-            finally:
-                with self._cache_locks_lock:
-                    lock_stack.pop_all().close()
-                    if not lock.in_use():
-                        del self._cache_locks[lock_id]
+        if self._lock.locked == "w":
+            return contextlib.ExitStack()
+        cache_folder = os.path.join(self._filesystem_path, ".Radicale.cache")
+        self._makedirs_synced(cache_folder)
+        lock_path = os.path.join(cache_folder,
+                                 ".Radicale.lock" + (".%s" % ns if ns else ""))
+        lock = FileBackedRwLock(lock_path)
+        return lock.acquire("w")
 
     def _load_item_cache(self, href, input_hash):
         cache_folder = os.path.join(self._filesystem_path, ".Radicale.cache",
@@ -1470,12 +1441,11 @@ class Collection(BaseCollection):
             self._load_item_cache(href, input_hash)
         vobject_item = None
         if input_hash != cache_hash:
-            with contextlib.ExitStack() as lock_stack:
+            with self._acquire_cache_lock("item"):
                 # Lock the item cache to prevent multpile processes from
                 # generating the same data in parallel.
                 # This improves the performance for multiple requests.
-                if self._lock.locked() == "r":
-                    lock_stack.enter_context(self._acquire_cache_lock("item"))
+                if self._lock.locked == "r":
                     # Check if another process created the file in the meantime
                     cache_hash, uid, etag, text, name, tag, start, end = \
                         self._load_item_cache(href, input_hash)
@@ -1592,7 +1562,7 @@ class Collection(BaseCollection):
 
     def get_meta(self, key=None):
         # reuse cached value if the storage is read-only
-        if self._lock.locked() == "w" or self._meta_cache is None:
+        if self._lock.locked == "w" or self._meta_cache is None:
             try:
                 try:
                     with open(self._props_path, encoding=self._encoding) as f:
@@ -1621,14 +1591,14 @@ class Collection(BaseCollection):
     @property
     def etag(self):
         # reuse cached value if the storage is read-only
-        if self._lock.locked() == "w" or self._etag_cache is None:
+        if self._lock.locked == "w" or self._etag_cache is None:
             self._etag_cache = super().etag
         return self._etag_cache
 
     @classmethod
     @contextmanager
     def acquire_lock(cls, mode, user=None):
-        with cls._lock.acquire_lock(mode):
+        with cls._lock.acquire(mode):
             yield
             # execute hook
             hook = cls.configuration.get("storage", "hook")
@@ -1653,123 +1623,54 @@ class Collection(BaseCollection):
 
 
 class FileBackedRwLock:
-    """A readers-Writer lock that can additionally lock a file.
-
-    All requests are processed in FIFO order.
-
-    """
+    """A readers-Writer lock that locks a file."""
 
-    def __init__(self, path=None, close_lock_file=True):
-        """Initilize a lock.
-
-        ``path`` the file that is used for locking (optional)
-
-        ``close_lock_file`` close the lock file, when unlocked and no requests
-        are pending
-
-        """
+    def __init__(self, path):
         self._path = path
-        self._close_lock_file = close_lock_file
-
-        self._lock = threading.Lock()
-        self._waiters = []
-        self._lock_file = None
-        self._lock_file_locked = False
         self._readers = 0
         self._writer = False
+        self._lock = threading.Lock()
 
+    @property
     def locked(self):
-        if self._writer:
-            return "w"
-        if self._readers:
-            return "r"
-        return ""
-
-    def in_use(self):
         with self._lock:
-            return self._waiters or self._readers or self._writer
+            if self._readers > 0:
+                return "r"
+            if self._writer:
+                return "w"
+            return ""
 
     @contextmanager
-    def acquire_lock(self, mode, sync_callback=None):
-        def condition():
-            if mode == "r":
-                return not self._writer
-            else:
-                return not self._writer and self._readers == 0
-
-        # Use a primitive lock which only works within one process as a
-        # precondition for inter-process file-based locking
-        with self._lock:
-            if sync_callback:
-                sync_callback()
-            if self._waiters or not condition():
-                # Use FIFO for access requests
-                waiter = threading.Condition(lock=self._lock)
-                self._waiters.append(waiter)
-                while True:
-                    waiter.wait()
-                    if condition():
-                        break
-                self._waiters.pop(0)
-            if mode == "r":
-                self._readers += 1
-                # Notify additional potential readers
-                if self._waiters:
-                    self._waiters[0].notify()
+    def acquire(self, mode):
+        if mode not in "rw":
+            raise ValueError("Invalid mode: %r" % mode)
+        with open(self._path, "w+") as lock_file:
+            if os.name == "nt":
+                handle = msvcrt.get_osfhandle(lock_file.fileno())
+                flags = LOCKFILE_EXCLUSIVE_LOCK if mode == "w" else 0
+                overlapped = Overlapped()
+                if not lock_file_ex(handle, flags, 0, 1, 0, overlapped):
+                    raise RuntimeError("Locking the storage failed: %s" %
+                                       ctypes.FormatError())
+            elif os.name == "posix":
+                _cmd = fcntl.LOCK_EX if mode == "w" else fcntl.LOCK_SH
+                try:
+                    fcntl.flock(lock_file.fileno(), _cmd)
+                except OSError as e:
+                    raise RuntimeError("Locking the storage failed: %s" %
+                                       e) from e
             else:
-                self._writer = True
-            if self._path and not self._lock_file_locked:
-                if not self._lock_file:
-                    self._lock_file = open(self._path, "w+")
-                if os.name == "nt":
-                    handle = msvcrt.get_osfhandle(self._lock_file.fileno())
-                    flags = LOCKFILE_EXCLUSIVE_LOCK if mode == "w" else 0
-                    overlapped = Overlapped()
-                    if not lock_file_ex(handle, flags, 0, 1, 0, overlapped):
-                        raise RuntimeError("Locking the storage failed "
-                                           "(can be disabled in the config): "
-                                           "%s" % ctypes.FormatError())
-                elif os.name == "posix":
-                    _cmd = fcntl.LOCK_EX if mode == "w" else fcntl.LOCK_SH
-                    try:
-                        fcntl.flock(self._lock_file.fileno(), _cmd)
-                    except OSError as e:
-                        raise RuntimeError("Locking the storage failed "
-                                           "(can be disabled in the config): "
-                                           "%s" % e) from e
-                else:
-                    raise RuntimeError("Locking the storage failed "
-                                       "(can be disabled in the config): "
-                                       "Unsupported operating system")
-                self._lock_file_locked = True
-        try:
-            yield
-        finally:
+                raise RuntimeError("Locking the storage failed: "
+                                   "Unsupported operating system")
             with self._lock:
                 if mode == "r":
-                    self._readers -= 1
+                    self._readers += 1
                 else:
+                    self._writer = True
+            try:
+                yield
+            finally:
+                with self._lock:
+                    if mode == "r":
+                        self._readers -= 1
                     self._writer = False
-                if self._lock_file_locked and self._readers == 0:
-                    if os.name == "nt":
-                        handle = msvcrt.get_osfhandle(self._lock_file.fileno())
-                        overlapped = Overlapped()
-                        if not unlock_file_ex(handle, 0, 1, 0, overlapped):
-                            raise RuntimeError("Unlocking the storage failed: "
-                                               "%s" % ctypes.FormatError())
-                    elif os.name == "posix":
-                        try:
-                            fcntl.flock(self._lock_file.fileno(),
-                                        fcntl.LOCK_UN)
-                        except OSError as e:
-                            raise RuntimeError("Unlocking the storage failed: "
-                                               "%s" % e) from e
-                    else:
-                        raise RuntimeError("Unlocking the storage failed: "
-                                           "Unsupported operating system")
-                    if self._close_lock_file and not self._waiters:
-                        self._lock_file.close()
-                        self._lock_file = None
-                    self._lock_file_locked = False
-                if self._waiters:
-                    self._waiters[0].notify()

radicale/tests/test_base.py

@@ -1428,8 +1428,6 @@ class BaseFileSystemTest(BaseTest):
         self.configuration["storage"]["filesystem_folder"] = self.colpath
         # Disable syncing to disk for better performance
         self.configuration["storage"]["filesystem_fsync"] = "False"
-        # Required on Windows, doesn't matter on Unix
-        self.configuration["storage"]["filesystem_close_lock_file"] = "True"
         self.application = Application(self.configuration)
 
     def teardown(self):

radicale/tests/test_rights.py

@@ -37,8 +37,6 @@ class TestBaseAuthRequests(BaseTest):
         self.configuration["storage"]["filesystem_folder"] = self.colpath
         # Disable syncing to disk for better performance
         self.configuration["storage"]["filesystem_fsync"] = "False"
-        # Required on Windows, doesn't matter on Unix
-        self.configuration["storage"]["filesystem_close_lock_file"] = "True"
 
     def teardown(self):
         shutil.rmtree(self.colpath)