mirror of
https://github.com/element-hq/synapse.git
synced 2024-11-22 17:46:08 +03:00
23740eaa3d
During the migration the automated script to update the copyright headers accidentally got rid of some of the existing copyright lines. Reinstate them.
401 lines
16 KiB
Python
401 lines
16 KiB
Python
#
|
|
# This file is licensed under the Affero General Public License (AGPL) version 3.
|
|
#
|
|
# Copyright 2016 OpenMarket Ltd
|
|
# Copyright (C) 2023 New Vector, Ltd
|
|
#
|
|
# This program is free software: you can redistribute it and/or modify
|
|
# it under the terms of the GNU Affero General Public License as
|
|
# published by the Free Software Foundation, either version 3 of the
|
|
# License, or (at your option) any later version.
|
|
#
|
|
# See the GNU Affero General Public License for more details:
|
|
# <https://www.gnu.org/licenses/agpl-3.0.html>.
|
|
#
|
|
# Originally licensed under the Apache License, Version 2.0:
|
|
# <http://www.apache.org/licenses/LICENSE-2.0>.
|
|
#
|
|
# [This file includes modifications made by New Vector Limited]
|
|
#
|
|
#
|
|
|
|
from typing import AsyncContextManager, Callable, Sequence, Tuple
|
|
|
|
from twisted.internet import defer
|
|
from twisted.internet.defer import CancelledError, Deferred
|
|
|
|
from synapse.util.async_helpers import ReadWriteLock
|
|
|
|
from tests import unittest
|
|
|
|
|
|
class ReadWriteLockTestCase(unittest.TestCase):
|
|
def _start_reader_or_writer(
|
|
self,
|
|
read_or_write: Callable[[str], AsyncContextManager],
|
|
key: str,
|
|
return_value: str,
|
|
) -> Tuple["Deferred[str]", "Deferred[None]", "Deferred[None]"]:
|
|
"""Starts a reader or writer which acquires the lock, blocks, then completes.
|
|
|
|
Args:
|
|
read_or_write: A function returning a context manager for a lock.
|
|
Either a bound `ReadWriteLock.read` or `ReadWriteLock.write`.
|
|
key: The key to read or write.
|
|
return_value: A string that the reader or writer will resolve with when
|
|
done.
|
|
|
|
Returns:
|
|
A tuple of three `Deferred`s:
|
|
* A cancellable `Deferred` for the entire read or write operation that
|
|
resolves with `return_value` on successful completion.
|
|
* A `Deferred` that resolves once the reader or writer acquires the lock.
|
|
* A `Deferred` that blocks the reader or writer. Must be resolved by the
|
|
caller to allow the reader or writer to release the lock and complete.
|
|
"""
|
|
acquired_d: "Deferred[None]" = Deferred()
|
|
unblock_d: "Deferred[None]" = Deferred()
|
|
|
|
async def reader_or_writer() -> str:
|
|
async with read_or_write(key):
|
|
acquired_d.callback(None)
|
|
await unblock_d
|
|
return return_value
|
|
|
|
d = defer.ensureDeferred(reader_or_writer())
|
|
return d, acquired_d, unblock_d
|
|
|
|
def _start_blocking_reader(
|
|
self, rwlock: ReadWriteLock, key: str, return_value: str
|
|
) -> Tuple["Deferred[str]", "Deferred[None]", "Deferred[None]"]:
|
|
"""Starts a reader which acquires the lock, blocks, then releases the lock.
|
|
|
|
See the docstring for `_start_reader_or_writer` for details about the arguments
|
|
and return values.
|
|
"""
|
|
return self._start_reader_or_writer(rwlock.read, key, return_value)
|
|
|
|
def _start_blocking_writer(
|
|
self, rwlock: ReadWriteLock, key: str, return_value: str
|
|
) -> Tuple["Deferred[str]", "Deferred[None]", "Deferred[None]"]:
|
|
"""Starts a writer which acquires the lock, blocks, then releases the lock.
|
|
|
|
See the docstring for `_start_reader_or_writer` for details about the arguments
|
|
and return values.
|
|
"""
|
|
return self._start_reader_or_writer(rwlock.write, key, return_value)
|
|
|
|
def _start_nonblocking_reader(
|
|
self, rwlock: ReadWriteLock, key: str, return_value: str
|
|
) -> Tuple["Deferred[str]", "Deferred[None]"]:
|
|
"""Starts a reader which acquires the lock, then releases it immediately.
|
|
|
|
See the docstring for `_start_reader_or_writer` for details about the arguments.
|
|
|
|
Returns:
|
|
A tuple of two `Deferred`s:
|
|
* A cancellable `Deferred` for the entire read operation that resolves with
|
|
`return_value` on successful completion.
|
|
* A `Deferred` that resolves once the reader acquires the lock.
|
|
"""
|
|
d, acquired_d, unblock_d = self._start_reader_or_writer(
|
|
rwlock.read, key, return_value
|
|
)
|
|
unblock_d.callback(None)
|
|
return d, acquired_d
|
|
|
|
def _start_nonblocking_writer(
|
|
self, rwlock: ReadWriteLock, key: str, return_value: str
|
|
) -> Tuple["Deferred[str]", "Deferred[None]"]:
|
|
"""Starts a writer which acquires the lock, then releases it immediately.
|
|
|
|
See the docstring for `_start_reader_or_writer` for details about the arguments.
|
|
|
|
Returns:
|
|
A tuple of two `Deferred`s:
|
|
* A cancellable `Deferred` for the entire write operation that resolves
|
|
with `return_value` on successful completion.
|
|
* A `Deferred` that resolves once the writer acquires the lock.
|
|
"""
|
|
d, acquired_d, unblock_d = self._start_reader_or_writer(
|
|
rwlock.write, key, return_value
|
|
)
|
|
unblock_d.callback(None)
|
|
return d, acquired_d
|
|
|
|
def _assert_first_n_resolved(
|
|
self, deferreds: Sequence["defer.Deferred[None]"], n: int
|
|
) -> None:
|
|
"""Assert that exactly the first n `Deferred`s in the given list are resolved.
|
|
|
|
Args:
|
|
deferreds: The list of `Deferred`s to be checked.
|
|
n: The number of `Deferred`s at the start of `deferreds` that should be
|
|
resolved.
|
|
"""
|
|
for i, d in enumerate(deferreds[:n]):
|
|
self.assertTrue(d.called, msg="deferred %d was unexpectedly unresolved" % i)
|
|
|
|
for i, d in enumerate(deferreds[n:]):
|
|
self.assertFalse(
|
|
d.called, msg="deferred %d was unexpectedly resolved" % (i + n)
|
|
)
|
|
|
|
def test_rwlock(self) -> None:
|
|
rwlock = ReadWriteLock()
|
|
key = "key"
|
|
|
|
ds = [
|
|
self._start_blocking_reader(rwlock, key, "0"),
|
|
self._start_blocking_reader(rwlock, key, "1"),
|
|
self._start_blocking_writer(rwlock, key, "2"),
|
|
self._start_blocking_writer(rwlock, key, "3"),
|
|
self._start_blocking_reader(rwlock, key, "4"),
|
|
self._start_blocking_reader(rwlock, key, "5"),
|
|
self._start_blocking_writer(rwlock, key, "6"),
|
|
]
|
|
# `Deferred`s that resolve when each reader or writer acquires the lock.
|
|
acquired_ds = [acquired_d for _, acquired_d, _ in ds]
|
|
# `Deferred`s that will trigger the release of locks when resolved.
|
|
release_ds = [release_d for _, _, release_d in ds]
|
|
|
|
# The first two readers should acquire their locks.
|
|
self._assert_first_n_resolved(acquired_ds, 2)
|
|
|
|
# Release one of the read locks. The next writer should not acquire the lock,
|
|
# because there is another reader holding the lock.
|
|
self._assert_first_n_resolved(acquired_ds, 2)
|
|
release_ds[0].callback(None)
|
|
self._assert_first_n_resolved(acquired_ds, 2)
|
|
|
|
# Release the other read lock. The next writer should acquire the lock.
|
|
self._assert_first_n_resolved(acquired_ds, 2)
|
|
release_ds[1].callback(None)
|
|
self._assert_first_n_resolved(acquired_ds, 3)
|
|
|
|
# Release the write lock. The next writer should acquire the lock.
|
|
self._assert_first_n_resolved(acquired_ds, 3)
|
|
release_ds[2].callback(None)
|
|
self._assert_first_n_resolved(acquired_ds, 4)
|
|
|
|
# Release the write lock. The next two readers should acquire locks.
|
|
self._assert_first_n_resolved(acquired_ds, 4)
|
|
release_ds[3].callback(None)
|
|
self._assert_first_n_resolved(acquired_ds, 6)
|
|
|
|
# Release one of the read locks. The next writer should not acquire the lock,
|
|
# because there is another reader holding the lock.
|
|
self._assert_first_n_resolved(acquired_ds, 6)
|
|
release_ds[5].callback(None)
|
|
self._assert_first_n_resolved(acquired_ds, 6)
|
|
|
|
# Release the other read lock. The next writer should acquire the lock.
|
|
self._assert_first_n_resolved(acquired_ds, 6)
|
|
release_ds[4].callback(None)
|
|
self._assert_first_n_resolved(acquired_ds, 7)
|
|
|
|
# Release the write lock.
|
|
release_ds[6].callback(None)
|
|
|
|
# Acquire and release the write and read locks one last time for good measure.
|
|
_, acquired_d = self._start_nonblocking_writer(rwlock, key, "last writer")
|
|
self.assertTrue(acquired_d.called)
|
|
|
|
_, acquired_d = self._start_nonblocking_reader(rwlock, key, "last reader")
|
|
self.assertTrue(acquired_d.called)
|
|
|
|
def test_lock_handoff_to_nonblocking_writer(self) -> None:
|
|
"""Test a writer handing the lock to another writer that completes instantly."""
|
|
rwlock = ReadWriteLock()
|
|
key = "key"
|
|
|
|
d1, _, unblock = self._start_blocking_writer(rwlock, key, "write 1 completed")
|
|
d2, _ = self._start_nonblocking_writer(rwlock, key, "write 2 completed")
|
|
self.assertFalse(d1.called)
|
|
self.assertFalse(d2.called)
|
|
|
|
# Unblock the first writer. The second writer will complete without blocking.
|
|
unblock.callback(None)
|
|
self.assertTrue(d1.called)
|
|
self.assertTrue(d2.called)
|
|
|
|
# The `ReadWriteLock` should operate as normal.
|
|
d3, _ = self._start_nonblocking_writer(rwlock, key, "write 3 completed")
|
|
self.assertTrue(d3.called)
|
|
|
|
def test_cancellation_while_holding_read_lock(self) -> None:
|
|
"""Test cancellation while holding a read lock.
|
|
|
|
A waiting writer should be given the lock when the reader holding the lock is
|
|
cancelled.
|
|
"""
|
|
rwlock = ReadWriteLock()
|
|
key = "key"
|
|
|
|
# 1. A reader takes the lock and blocks.
|
|
reader_d, _, _ = self._start_blocking_reader(rwlock, key, "read completed")
|
|
|
|
# 2. A writer waits for the reader to complete.
|
|
writer_d, _ = self._start_nonblocking_writer(rwlock, key, "write completed")
|
|
self.assertFalse(writer_d.called)
|
|
|
|
# 3. The reader is cancelled.
|
|
reader_d.cancel()
|
|
self.failureResultOf(reader_d, CancelledError)
|
|
|
|
# 4. The writer should take the lock and complete.
|
|
self.assertTrue(
|
|
writer_d.called, "Writer is stuck waiting for a cancelled reader"
|
|
)
|
|
self.assertEqual("write completed", self.successResultOf(writer_d))
|
|
|
|
def test_cancellation_while_holding_write_lock(self) -> None:
|
|
"""Test cancellation while holding a write lock.
|
|
|
|
A waiting reader should be given the lock when the writer holding the lock is
|
|
cancelled.
|
|
"""
|
|
rwlock = ReadWriteLock()
|
|
key = "key"
|
|
|
|
# 1. A writer takes the lock and blocks.
|
|
writer_d, _, _ = self._start_blocking_writer(rwlock, key, "write completed")
|
|
|
|
# 2. A reader waits for the writer to complete.
|
|
reader_d, _ = self._start_nonblocking_reader(rwlock, key, "read completed")
|
|
self.assertFalse(reader_d.called)
|
|
|
|
# 3. The writer is cancelled.
|
|
writer_d.cancel()
|
|
self.failureResultOf(writer_d, CancelledError)
|
|
|
|
# 4. The reader should take the lock and complete.
|
|
self.assertTrue(
|
|
reader_d.called, "Reader is stuck waiting for a cancelled writer"
|
|
)
|
|
self.assertEqual("read completed", self.successResultOf(reader_d))
|
|
|
|
def test_cancellation_while_waiting_for_read_lock(self) -> None:
|
|
"""Test cancellation while waiting for a read lock.
|
|
|
|
Tests that cancelling a waiting reader:
|
|
* does not cancel the writer it is waiting on
|
|
* does not cancel the next writer waiting on it
|
|
* does not allow the next writer to acquire the lock before an earlier writer
|
|
has finished
|
|
* does not keep the next writer waiting indefinitely
|
|
|
|
These correspond to the asserts with explicit messages.
|
|
"""
|
|
rwlock = ReadWriteLock()
|
|
key = "key"
|
|
|
|
# 1. A writer takes the lock and blocks.
|
|
writer1_d, _, unblock_writer1 = self._start_blocking_writer(
|
|
rwlock, key, "write 1 completed"
|
|
)
|
|
|
|
# 2. A reader waits for the first writer to complete.
|
|
# This reader will be cancelled later.
|
|
reader_d, _ = self._start_nonblocking_reader(rwlock, key, "read completed")
|
|
self.assertFalse(reader_d.called)
|
|
|
|
# 3. A second writer waits for both the first writer and the reader to complete.
|
|
writer2_d, _ = self._start_nonblocking_writer(rwlock, key, "write 2 completed")
|
|
self.assertFalse(writer2_d.called)
|
|
|
|
# 4. The waiting reader is cancelled.
|
|
# Neither of the writers should be cancelled.
|
|
# The second writer should still be waiting, but only on the first writer.
|
|
reader_d.cancel()
|
|
self.failureResultOf(reader_d, CancelledError)
|
|
self.assertFalse(writer1_d.called, "First writer was unexpectedly cancelled")
|
|
self.assertFalse(
|
|
writer2_d.called,
|
|
"Second writer was unexpectedly cancelled or given the lock before the "
|
|
"first writer finished",
|
|
)
|
|
|
|
# 5. Unblock the first writer, which should complete.
|
|
unblock_writer1.callback(None)
|
|
self.assertEqual("write 1 completed", self.successResultOf(writer1_d))
|
|
|
|
# 6. The second writer should take the lock and complete.
|
|
self.assertTrue(
|
|
writer2_d.called, "Second writer is stuck waiting for a cancelled reader"
|
|
)
|
|
self.assertEqual("write 2 completed", self.successResultOf(writer2_d))
|
|
|
|
def test_cancellation_while_waiting_for_write_lock(self) -> None:
|
|
"""Test cancellation while waiting for a write lock.
|
|
|
|
Tests that cancelling a waiting writer:
|
|
* does not cancel the reader or writer it is waiting on
|
|
* does not cancel the next writer waiting on it
|
|
* does not allow the next writer to acquire the lock before an earlier reader
|
|
and writer have finished
|
|
* does not keep the next writer waiting indefinitely
|
|
|
|
These correspond to the asserts with explicit messages.
|
|
"""
|
|
rwlock = ReadWriteLock()
|
|
key = "key"
|
|
|
|
# 1. A reader takes the lock and blocks.
|
|
reader_d, _, unblock_reader = self._start_blocking_reader(
|
|
rwlock, key, "read completed"
|
|
)
|
|
|
|
# 2. A writer waits for the reader to complete.
|
|
writer1_d, _, unblock_writer1 = self._start_blocking_writer(
|
|
rwlock, key, "write 1 completed"
|
|
)
|
|
|
|
# 3. A second writer waits for both the reader and first writer to complete.
|
|
# This writer will be cancelled later.
|
|
writer2_d, _ = self._start_nonblocking_writer(rwlock, key, "write 2 completed")
|
|
self.assertFalse(writer2_d.called)
|
|
|
|
# 4. A third writer waits for the second writer to complete.
|
|
writer3_d, _ = self._start_nonblocking_writer(rwlock, key, "write 3 completed")
|
|
self.assertFalse(writer3_d.called)
|
|
|
|
# 5. The second writer is cancelled, but continues waiting for the lock.
|
|
# The reader, first writer and third writer should not be cancelled.
|
|
# The first writer should still be waiting on the reader.
|
|
# The third writer should still be waiting on the second writer.
|
|
writer2_d.cancel()
|
|
self.assertNoResult(writer2_d)
|
|
self.assertFalse(reader_d.called, "Reader was unexpectedly cancelled")
|
|
self.assertFalse(writer1_d.called, "First writer was unexpectedly cancelled")
|
|
self.assertFalse(
|
|
writer3_d.called,
|
|
"Third writer was unexpectedly cancelled or given the lock before the first "
|
|
"writer finished",
|
|
)
|
|
|
|
# 6. Unblock the reader, which should complete.
|
|
# The first writer should be given the lock and block.
|
|
# The third writer should still be waiting on the second writer.
|
|
unblock_reader.callback(None)
|
|
self.assertEqual("read completed", self.successResultOf(reader_d))
|
|
self.assertNoResult(writer2_d)
|
|
self.assertFalse(
|
|
writer3_d.called,
|
|
"Third writer was unexpectedly given the lock before the first writer "
|
|
"finished",
|
|
)
|
|
|
|
# 7. Unblock the first writer, which should complete.
|
|
unblock_writer1.callback(None)
|
|
self.assertEqual("write 1 completed", self.successResultOf(writer1_d))
|
|
|
|
# 8. The second writer should take the lock and release it immediately, since it
|
|
# has been cancelled.
|
|
self.failureResultOf(writer2_d, CancelledError)
|
|
|
|
# 9. The third writer should take the lock and complete.
|
|
self.assertTrue(
|
|
writer3_d.called, "Third writer is stuck waiting for a cancelled writer"
|
|
)
|
|
self.assertEqual("write 3 completed", self.successResultOf(writer3_d))
|