[HZ-5434] FencedLock for Asyncio

hazelcast/asyncio/__init__.py

@@ -6,6 +6,7 @@
     "EntryEventCallable",
     "FlakeIdGenerator",
     "Executor",
+    "FencedLock",
     "HazelcastClient",
     "List",
     "Map",
@@ -39,3 +40,4 @@
 from hazelcast.internal.asyncio_proxy.atomic_reference import AtomicReference
 from hazelcast.internal.asyncio_proxy.countdown_latch import CountDownLatch
 from hazelcast.internal.asyncio_proxy.semaphore import Semaphore
+from hazelcast.internal.asyncio_proxy.fenced_lock import FencedLock

hazelcast/internal/asyncio_proxy/cp_manager.py

@@ -1,15 +1,19 @@
+import asyncio
+
 from hazelcast.cp import (
     _without_default_group_name,
     _get_object_name_for_proxy,
     ATOMIC_LONG_SERVICE,
     ATOMIC_REFERENCE_SERVICE,
     COUNT_DOWN_LATCH_SERVICE,
     SEMAPHORE_SERVICE,
+    LOCK_SERVICE,
 )
 from hazelcast.internal.asyncio_invocation import Invocation
 from hazelcast.internal.asyncio_proxy.atomic_long import AtomicLong
 from hazelcast.internal.asyncio_proxy.atomic_reference import AtomicReference
 from hazelcast.internal.asyncio_proxy.countdown_latch import CountDownLatch
+from hazelcast.internal.asyncio_proxy.fenced_lock import FencedLock
 from hazelcast.internal.asyncio_proxy.semaphore import (
     Semaphore,
     SessionAwareSemaphore,
@@ -109,6 +113,25 @@ async def get_count_down_latch(self, name: str) -> CountDownLatch:
         """
         return await self._proxy_manager.get_or_create(COUNT_DOWN_LATCH_SERVICE, name)
 
+    async def get_lock(self, name: str) -> FencedLock:
+        """Returns the distributed FencedLock instance with given name.
+
+        The instance is created on CP Subsystem.
+
+        If no group name is given within the ``name`` argument, then the
+        FencedLock instance will be created on the DEFAULT CP group.
+        If a group name is given, like ``.get_lock("myLock@group1")``,
+        the given group will be initialized first, if not initialized
+        already, and then the instance will be created on this group.
+
+        Args:
+            name: Name of the FencedLock
+
+        Returns:
+            The FencedLock proxy for the given name.
+        """
+        return await self._proxy_manager.get_or_create(LOCK_SERVICE, name)
+
     async def get_semaphore(self, name: str) -> Semaphore:
         """Returns the distributed Semaphore instance with given name.
 
@@ -132,6 +155,8 @@ async def get_semaphore(self, name: str) -> Semaphore:
 class CPProxyManager:
     def __init__(self, context):
         self._context = context
+        self._lock_proxies = dict()  # proxy_name to FencedLock
+        self._mux = asyncio.Lock()  # Guards the _lock_proxies
 
     async def get_or_create(self, service_name, proxy_name):
         proxy_name = _without_default_group_name(proxy_name)
@@ -144,11 +169,26 @@ async def get_or_create(self, service_name, proxy_name):
             return AtomicReference(self._context, group_id, service_name, proxy_name, object_name)
         elif service_name == COUNT_DOWN_LATCH_SERVICE:
             return CountDownLatch(self._context, group_id, service_name, proxy_name, object_name)
+        elif service_name == LOCK_SERVICE:
+            return await self._create_fenced_lock(group_id, proxy_name, object_name)
         elif service_name == SEMAPHORE_SERVICE:
             return await self._create_semaphore(group_id, proxy_name, object_name)
 
         raise ValueError("Unknown service name: %s" % service_name)
 
+    async def _create_fenced_lock(self, group_id, proxy_name, object_name):
+        async with self._mux:
+            proxy = self._lock_proxies.get(proxy_name, None)
+            if proxy:
+                if proxy.get_group_id() != group_id:
+                    self._lock_proxies.pop(proxy_name, None)
+                else:
+                    return proxy
+
+            proxy = FencedLock(self._context, group_id, LOCK_SERVICE, proxy_name, object_name)
+            self._lock_proxies[proxy_name] = proxy
+            return proxy
+
     async def _create_semaphore(self, group_id, proxy_name, object_name):
         codec = semaphore_get_semaphore_type_codec
         request = codec.encode_request(proxy_name)

hazelcast/internal/asyncio_proxy/fenced_lock.py

@@ -0,0 +1,257 @@
+import time
+import uuid
+
+from hazelcast.errors import (
+    LockOwnershipLostError,
+    IllegalMonitorStateError,
+    SessionExpiredError,
+    WaitKeyCancelledError,
+    LockAcquireLimitReachedError,
+)
+from hazelcast.internal.asyncio_proxy.base import task_id
+from hazelcast.internal.asyncio_proxy.cp import SessionAwareCPProxy
+from hazelcast.protocol.codec import (
+    fenced_lock_unlock_codec,
+    fenced_lock_get_lock_ownership_codec,
+    fenced_lock_try_lock_codec,
+    fenced_lock_lock_codec,
+)
+from hazelcast.proxy.cp.fenced_lock import _LockOwnershipState
+from hazelcast.util import to_millis
+
+_NO_SESSION_ID = -1
+
+
+class FencedLock(SessionAwareCPProxy):
+    """A linearizable, distributed lock.
+
+    FencedLock is CP with respect to the CAP principle. It works on top
+    of the Raft consensus algorithm. It offers linearizability during crash-stop
+    failures and network partitions. If a network partition occurs, it remains
+    available on at most one side of the partition.
+
+    FencedLock works on top of CP sessions. Please refer to CP Session
+    documentation section for more information.
+
+    By default, FencedLock is reentrant. Once a caller acquires
+    the lock, it can acquire the lock reentrantly as many times as it wants
+    in a linearizable manner. You can configure the reentrancy behaviour
+    on the member side. For instance, reentrancy can be disabled and
+    FencedLock can work as a non-reentrant mutex. One can also set
+    a custom reentrancy limit. When the reentrancy limit is reached,
+    FencedLock does not block a lock call. Instead, it fails with
+    ``LockAcquireLimitReachedError`` or a specified return value.
+    Please check the locking methods to see details about the behaviour.
+    """
+
+    INVALID_FENCE = 0
+
+    def __init__(self, context, group_id, service_name, proxy_name, object_name):
+        super(FencedLock, self).__init__(context, group_id, service_name, proxy_name, object_name)
+        self._lock_session_ids = dict()  # thread-id to session id that has acquired the lock
+
+    async def lock(self) -> int:
+        invocation_uuid = uuid.uuid4()
+        return await self._do_lock(task_id(), invocation_uuid)
+
+    async def try_lock(self, timeout: float = 0) -> int:
+        invocation_uuid = uuid.uuid4()
+        timeout = max(0.0, timeout)
+        return await self._do_try_lock(task_id(), invocation_uuid, timeout)
+
+    async def unlock(self) -> None:
+        current_thread_id = task_id()
+        session_id = self._get_session_id()
+
+        # the order of the following checks is important
+        self._verify_locked_session_id_if_present(current_thread_id, session_id, False)
+        if session_id == _NO_SESSION_ID:
+            self._lock_session_ids.pop(current_thread_id, None)
+            raise self._new_illegal_monitor_state_error()
+
+        try:
+            still_locked_by_the_current_thread = await self._request_unlock(
+                session_id, current_thread_id, uuid.uuid4()
+            )
+            if still_locked_by_the_current_thread:
+                self._lock_session_ids[current_thread_id] = session_id
+            else:
+                self._lock_session_ids.pop(current_thread_id, None)
+
+            self._release_session(session_id)
+        except SessionExpiredError:
+            self._invalidate_session(session_id)
+            self._lock_session_ids.pop(current_thread_id, None)
+            raise self._new_lock_ownership_lost_error(session_id)
+        except IllegalMonitorStateError as e:
+            self._lock_session_ids.pop(current_thread_id, None)
+            raise e
+
+    async def is_locked(self) -> bool:
+        current_thread_id = task_id()
+        session_id = self._get_session_id()
+        self._verify_locked_session_id_if_present(current_thread_id, session_id, False)
+        f = await self._request_get_lock_ownership_state()
+        state = _LockOwnershipState(f)
+        if state.is_locked_by(session_id, current_thread_id):
+            self._lock_session_ids[current_thread_id] = session_id
+            return True
+
+        self._verify_no_locked_session_id_present(current_thread_id)
+        return state.is_locked()
+
+    async def is_locked_by_current_task(self) -> bool:
+        current_thread_id = task_id()
+        session_id = self._get_session_id()
+        self._verify_locked_session_id_if_present(current_thread_id, session_id, False)
+        f = await self._request_get_lock_ownership_state()
+        state = _LockOwnershipState(f)
+        locked_by_the_current_thread = state.is_locked_by(session_id, current_thread_id)
+        if locked_by_the_current_thread:
+            self._lock_session_ids[current_thread_id] = session_id
+        else:
+            self._verify_no_locked_session_id_present(current_thread_id)
+
+        return locked_by_the_current_thread
+
+    async def get_lock_count(self) -> int:
+        current_thread_id = task_id()
+        session_id = self._get_session_id()
+        self._verify_locked_session_id_if_present(current_thread_id, session_id, False)
+        f = await self._request_get_lock_ownership_state()
+        state = _LockOwnershipState(f)
+        if state.is_locked_by(session_id, current_thread_id):
+            self._lock_session_ids[current_thread_id] = session_id
+        else:
+            self._verify_no_locked_session_id_present(current_thread_id)
+
+        return state.lock_count
+
+    async def destroy(self) -> None:
+        self._lock_session_ids.clear()
+        return await super(FencedLock, self).destroy()
+
+    async def _do_lock(self, current_thread_id, invocation_uuid):
+        async def do_lock_once(session_id):
+            self._verify_locked_session_id_if_present(current_thread_id, session_id, True)
+
+            try:
+                fence = await self._request_lock(session_id, current_thread_id, invocation_uuid)
+            except SessionExpiredError:
+                self._invalidate_session(session_id)
+                self._verify_no_locked_session_id_present(current_thread_id)
+                return await self._do_lock(current_thread_id, invocation_uuid)
+            except WaitKeyCancelledError:
+                self._release_session(session_id)
+                raise IllegalMonitorStateError(
+                    "Lock(%s) not acquired because the lock call on the CP group "
+                    "is cancelled, possibly because of another indeterminate call "
+                    "from the same task." % self._object_name
+                )
+            except Exception as e:
+                self._release_session(session_id)
+                raise e
+
+            if fence != self.INVALID_FENCE:
+                self._lock_session_ids[current_thread_id] = session_id
+                return fence
+
+            self._release_session(session_id)
+            raise LockAcquireLimitReachedError(
+                "Lock(%s) reentrant lock limit is already reached!" % self._object_name
+            )
+
+        session_id = await self._acquire_session()
+        return await do_lock_once(session_id)
+
+    async def _do_try_lock(self, current_thread_id, invocation_uuid, timeout):
+        start = time.time()
+
+        async def do_try_lock_once(session_id):
+            self._verify_locked_session_id_if_present(current_thread_id, session_id, True)
+
+            try:
+                fence = await self._request_try_lock(
+                    session_id, current_thread_id, invocation_uuid, timeout
+                )
+            except SessionExpiredError:
+                self._invalidate_session(session_id)
+                self._verify_no_locked_session_id_present(current_thread_id)
+                remaining_timeout = timeout - (time.time() - start)
+                if remaining_timeout <= 0:
+                    return self.INVALID_FENCE
+                return await self._do_try_lock(
+                    current_thread_id, invocation_uuid, remaining_timeout
+                )
+            except WaitKeyCancelledError:
+                self._release_session(session_id)
+                return self.INVALID_FENCE
+            except Exception as e:
+                self._release_session(session_id)
+                raise e
+
+            if fence != self.INVALID_FENCE:
+                self._lock_session_ids[current_thread_id] = session_id
+            else:
+                self._release_session(session_id)
+
+            return fence
+
+        session_id = await self._acquire_session()
+        return await do_try_lock_once(session_id)
+
+    def _verify_locked_session_id_if_present(self, current_thread_id, session_id, release_session):
+        lock_session_id = self._lock_session_ids.get(current_thread_id, None)
+        if lock_session_id and lock_session_id != session_id:
+            self._lock_session_ids.pop(current_thread_id, None)
+            if release_session:
+                self._release_session(session_id)
+
+            raise self._new_lock_ownership_lost_error(lock_session_id)
+
+    def _verify_no_locked_session_id_present(self, current_thread_id):
+        lock_session_id = self._lock_session_ids.pop(current_thread_id, None)
+        if lock_session_id:
+            raise self._new_lock_ownership_lost_error(lock_session_id)
+
+    def _new_lock_ownership_lost_error(self, lock_session_id):
+        return LockOwnershipLostError(
+            "Current task is not the owner of the Lock(%s) because its "
+            "Session(%s) is closed by the server." % (self._proxy_name, lock_session_id)
+        )
+
+    def _new_illegal_monitor_state_error(self):
+        return IllegalMonitorStateError(
+            "Current task is not the owner of the Lock(%s)" % self._proxy_name
+        )
+
+    async def _request_lock(self, session_id, current_thread_id, invocation_uuid):
+        codec = fenced_lock_lock_codec
+        request = codec.encode_request(
+            self._group_id, self._object_name, session_id, current_thread_id, invocation_uuid
+        )
+        return await self._ainvoke(request, codec.decode_response)
+
+    async def _request_try_lock(self, session_id, current_thread_id, invocation_uuid, timeout):
+        codec = fenced_lock_try_lock_codec
+        request = codec.encode_request(
+            self._group_id,
+            self._object_name,
+            session_id,
+            current_thread_id,
+            invocation_uuid,
+            to_millis(timeout),
+        )
+        return await self._ainvoke(request, codec.decode_response)
+
+    async def _request_unlock(self, session_id, current_thread_id, invocation_uuid):
+        codec = fenced_lock_unlock_codec
+        request = codec.encode_request(
+            self._group_id, self._object_name, session_id, current_thread_id, invocation_uuid
+        )
+        return await self._ainvoke(request, codec.decode_response)
+
+    async def _request_get_lock_ownership_state(self):
+        codec = fenced_lock_get_lock_ownership_codec
+        request = codec.encode_request(self._group_id, self._object_name)
+        return await self._ainvoke(request, codec.decode_response)