Revert "Solve Kombu filesystem transport not thread safe (#1593)" (#1595)

This reverts commit 8699920e050727d385a6d5a19c939e55a86688d6.

2 files changed, 29 insertions, 170 deletions

diff --git a/kombu/transport/filesystem.py b/kombu/transport/filesystem.py
index eb07bba6..92d8c4e4 100644
--- a/kombu/transport/filesystem.py
+++ b/kombu/transport/filesystem.py
@@ -93,7 +93,6 @@ from __future__ import annotations
 
 import os
 import shutil
-import signal
 import tempfile
 import uuid
 from collections import namedtuple
@@ -112,26 +111,6 @@ from . import virtual
 VERSION = (1, 0, 0)
 __version__ = '.'.join(map(str, VERSION))
 
-
-@contextmanager
-def timeout_manager(seconds: int):
-    def timeout_handler(signum, frame):
-        # Now that flock retries automatically when interrupted, we need
-        # an exception to stop it
-        # This exception will propagate on the main thread,
-        # make sure you're calling flock there
-        raise InterruptedError
-
-    original_handler = signal.signal(signal.SIGALRM, timeout_handler)
-
-    try:
-        signal.alarm(seconds)
-        yield
-    finally:
-        signal.alarm(0)
-        signal.signal(signal.SIGALRM, original_handler)
-
-
 # needs win32all to work on Windows
 if os.name == 'nt':
 
@@ -159,7 +138,7 @@ if os.name == 'nt':
 elif os.name == 'posix':
 
     import fcntl
-    from fcntl import LOCK_EX, LOCK_SH
+    from fcntl import LOCK_EX, LOCK_NB, LOCK_SH  # noqa
 
     def lock(file, flags):
         """Create file lock."""
@@ -175,21 +154,6 @@ else:
         'Filesystem plugin only defined for NT and POSIX platforms')
 
 
-@contextmanager
-def lock_with_timeout(file, flags, timeout: int = 1):
-    with timeout_manager(timeout):
-        try:
-            lock(file, flags)
-            yield
-        except InterruptedError:
-            # Catch the exception raised by the handler
-            # If we weren't raising an exception,
-            # flock would automatically retry on signals
-            raise BlockingIOError("Lock timed out")
-        finally:
-            unlock(file)
-
-
 exchange_queue_t = namedtuple("exchange_queue_t",
                               ["routing_key", "pattern", "queue"])
 
@@ -204,14 +168,18 @@ class Channel(virtual.Channel):
         file = self.control_folder / f"{exchange}.exchange"
         if "w" in mode:
             self.control_folder.mkdir(exist_ok=True)
-        lock_mode = LOCK_EX if "w" in mode else LOCK_SH
+        f_obj = file.open(mode)
 
-        with file.open(mode) as f_obj:
-            try:
-                with lock_with_timeout(f_obj, lock_mode):
-                    yield f_obj
-            except OSError as err:
-                raise ChannelError(f"Cannot open {file}") from err
+        try:
+            if "w" in mode:
+                lock(f_obj, LOCK_EX)
+            yield f_obj
+        except OSError:
+            raise ChannelError(f"Cannot open {file}")
+        finally:
+            if "w" in mode:
+                unlock(f_obj)
+            f_obj.close()
 
     def get_table(self, exchange):
         try:
@@ -241,12 +209,15 @@ class Channel(virtual.Channel):
         filename = os.path.join(self.data_folder_out, filename)
 
         try:
-            with open(filename, 'wb') as f:
-                with lock_with_timeout(f, LOCK_EX):
-                    f.write(str_to_bytes(dumps(payload)))
-        except OSError as err:
+            f = open(filename, 'wb')
+            lock(f, LOCK_EX)
+            f.write(str_to_bytes(dumps(payload)))
+        except OSError:
             raise ChannelError(
-                f'Cannot add file {filename!r} to directory') from err
+                f'Cannot add file {filename!r} to directory')
+        finally:
+            unlock(f)
+            f.close()
 
     def _get(self, queue):
         """Get next message from `queue`."""
@@ -274,14 +245,14 @@ class Channel(virtual.Channel):
 
             filename = os.path.join(processed_folder, filename)
             try:
-                with open(filename, 'rb') as f:
-                    with lock_with_timeout(f, LOCK_SH):
-                        payload = f.read()
-                        if not self.store_processed:
-                            os.remove(filename)
-            except OSError as err:
+                f = open(filename, 'rb')
+                payload = f.read()
+                f.close()
+                if not self.store_processed:
+                    os.remove(filename)
+            except OSError:
                 raise ChannelError(
-                    f'Cannot read file {filename!r} from queue.') from err
+                    f'Cannot read file {filename!r} from queue.')
 
             return loads(bytes_to_str(payload))
 
@@ -301,9 +272,7 @@ class Channel(virtual.Channel):
                     continue
 
                 filename = os.path.join(self.data_folder_in, filename)
-                with open(filename, 'wb') as f:
-                    with lock_with_timeout(f, LOCK_EX):
-                        os.remove(filename)
+                os.remove(filename)
 
                 count += 1
 
diff --git a/t/unit/transport/test_filesystem.py b/t/unit/transport/test_filesystem.py
index c452e7ca..b22e3b8d 100644
--- a/t/unit/transport/test_filesystem.py
+++ b/t/unit/transport/test_filesystem.py
@@ -1,19 +1,17 @@
 from __future__ import annotations
 
 import tempfile
-from fcntl import LOCK_EX, LOCK_NB, LOCK_SH
 from queue import Empty
-from unittest.mock import call, patch
 
 import pytest
 
 import t.skip
 from kombu import Connection, Consumer, Exchange, Producer, Queue
-from kombu.transport.filesystem import lock, unlock
 
 
 @t.skip.if_win32
 class test_FilesystemTransport:
+
     def setup(self):
         self.channels = set()
         try:
@@ -147,7 +145,6 @@ class test_FilesystemTransport:
 
 @t.skip.if_win32
 class test_FilesystemFanout:
-
     def setup(self):
         try:
             data_folder_in = tempfile.mkdtemp()
@@ -237,110 +234,3 @@ class test_FilesystemFanout:
         assert self.q2(self.consume_channel).get()
         self.q2(self.consume_channel).purge()
         assert self.q2(self.consume_channel).get() is None
-
-
-@t.skip.if_win32
-class test_FilesystemLock:
-    def test_lock(self):
-        file_obj1 = tempfile.NamedTemporaryFile()
-        with open(file_obj1.name) as file_obj2:
-            lock(file_obj1, LOCK_SH)
-            with pytest.raises(BlockingIOError):
-                lock(file_obj2, LOCK_EX | LOCK_NB)
-
-            lock(file_obj2, LOCK_SH)
-            unlock(file_obj2)
-
-            unlock(file_obj1)
-            lock(file_obj2, LOCK_EX)
-            unlock(file_obj2)
-        file_obj1.close()
-
-
-@t.skip.if_win32
-class test_FilesystemLockDuringProcess:
-    def setup(self):
-        try:
-            data_folder_in = tempfile.mkdtemp()
-            data_folder_out = tempfile.mkdtemp()
-            control_folder = tempfile.mkdtemp()
-        except Exception:
-            pytest.skip("filesystem transport: cannot create tempfiles")
-
-        self.consumer_connection = Connection(
-            transport="filesystem",
-            transport_options={
-                "data_folder_in": data_folder_in,
-                "data_folder_out": data_folder_out,
-                "control_folder": control_folder,
-            },
-        )
-        self.consume_channel = self.consumer_connection.channel()
-        self.produce_connection = Connection(
-            transport="filesystem",
-            transport_options={
-                "data_folder_in": data_folder_out,
-                "data_folder_out": data_folder_in,
-                "control_folder": control_folder,
-            },
-        )
-        self.producer_channel = self.produce_connection.channel()
-        self.exchange = Exchange("filesystem_exchange_lock", type="fanout")
-        self.q = Queue("queue1", exchange=self.exchange)
-
-    def teardown(self):
-        # make sure we don't attempt to restore messages at shutdown.
-        for channel in [self.producer_channel, self.consumer_connection]:
-            try:
-                channel._qos._dirty.clear()
-            except AttributeError:
-                pass
-            try:
-                channel._qos._delivered.clear()
-            except AttributeError:
-                pass
-
-    def test_lock_during_process(self):
-        producer = Producer(self.producer_channel, self.exchange)
-
-        with patch("kombu.transport.filesystem.lock") as lock_m, patch(
-            "kombu.transport.filesystem.unlock"
-        ) as unlock_m:
-            consumer = Consumer(self.consume_channel, self.q)
-            assert unlock_m.call_count == 1
-            lock_m.assert_called_once_with(unlock_m.call_args[0][0], LOCK_EX)
-
-        self.q(self.consume_channel).declare()
-        with patch("kombu.transport.filesystem.lock") as lock_m, patch(
-            "kombu.transport.filesystem.unlock"
-        ) as unlock_m:
-            producer.publish({"foo": 1})
-            assert unlock_m.call_count == 2
-            assert lock_m.call_count == 2
-            exchange_file_obj = unlock_m.call_args_list[0][0][0]
-            msg_file_obj = unlock_m.call_args_list[1][0][0]
-            assert lock_m.call_args_list == [call(exchange_file_obj, LOCK_SH),
-                                             call(msg_file_obj, LOCK_EX)]
-
-        def callback(_, message):
-            message.ack()
-
-        consumer.register_callback(callback)
-        consumer.consume()
-
-        with patch("kombu.transport.filesystem.lock") as lock_m, patch(
-            "kombu.transport.filesystem.unlock"
-        ) as unlock_m:
-            self.consume_channel.drain_events()
-            assert lock_m.call_count == 1
-            assert unlock_m.call_count == 1
-            lock_m.assert_called_once_with(unlock_m.call_args[0][0], LOCK_SH)
-
-        producer.publish({"foo": 0})
-        with patch("kombu.transport.filesystem.lock") as lock_m, patch(
-            "kombu.transport.filesystem.unlock"
-        ) as unlock_m:
-            self.q(self.consume_channel).purge()
-            assert lock_m.call_count == 1
-            assert unlock_m.call_count == 1
-            lock_m.assert_called_once_with(unlock_m.call_args[0][0], LOCK_EX)