Enable AsyncIO cluster mode lock (#2446)

Co-authored-by: Chayim <chayim@users.noreply.github.com>

CHANGES

@@ -24,6 +24,7 @@
     * ClusterPipeline Doesn't Handle ConnectionError for Dead Hosts (#2225)
     * Remove compatibility code for old versions of Hiredis, drop Packaging dependency
     * The `deprecated` library is no longer a dependency
+    * Enable Lock for asyncio cluster mode
 
 * 4.1.3 (Feb 8, 2022)
     * Fix flushdb and flushall (#1926)

redis/asyncio/cluster.py

@@ -24,6 +24,7 @@
     SSLConnection,
     parse_url,
 )
+from redis.asyncio.lock import Lock
 from redis.asyncio.parser import CommandsParser
 from redis.client import EMPTY_RESPONSE, NEVER_DECODE, AbstractRedis
 from redis.cluster import (
@@ -764,6 +765,72 @@ def pipeline(
 
         return ClusterPipeline(self)
 
+    def lock(
+        self,
+        name: KeyT,
+        timeout: Optional[float] = None,
+        sleep: float = 0.1,
+        blocking_timeout: Optional[float] = None,
+        lock_class: Optional[Type[Lock]] = None,
+        thread_local: bool = True,
+    ) -> Lock:
+        """
+        Return a new Lock object using key ``name`` that mimics
+        the behavior of threading.Lock.
+
+        If specified, ``timeout`` indicates a maximum life for the lock.
+        By default, it will remain locked until release() is called.
+
+        ``sleep`` indicates the amount of time to sleep per loop iteration
+        when the lock is in blocking mode and another client is currently
+        holding the lock.
+
+        ``blocking_timeout`` indicates the maximum amount of time in seconds to
+        spend trying to acquire the lock. A value of ``None`` indicates
+        continue trying forever. ``blocking_timeout`` can be specified as a
+        float or integer, both representing the number of seconds to wait.
+
+        ``lock_class`` forces the specified lock implementation. Note that as
+        of redis-py 3.0, the only lock class we implement is ``Lock`` (which is
+        a Lua-based lock). So, it's unlikely you'll need this parameter, unless
+        you have created your own custom lock class.
+
+        ``thread_local`` indicates whether the lock token is placed in
+        thread-local storage. By default, the token is placed in thread local
+        storage so that a thread only sees its token, not a token set by
+        another thread. Consider the following timeline:
+
+            time: 0, thread-1 acquires `my-lock`, with a timeout of 5 seconds.
+                     thread-1 sets the token to "abc"
+            time: 1, thread-2 blocks trying to acquire `my-lock` using the
+                     Lock instance.
+            time: 5, thread-1 has not yet completed. redis expires the lock
+                     key.
+            time: 5, thread-2 acquired `my-lock` now that it's available.
+                     thread-2 sets the token to "xyz"
+            time: 6, thread-1 finishes its work and calls release(). if the
+                     token is *not* stored in thread local storage, then
+                     thread-1 would see the token value as "xyz" and would be
+                     able to successfully release the thread-2's lock.
+
+        In some use cases it's necessary to disable thread local storage. For
+        example, if you have code where one thread acquires a lock and passes
+        that lock instance to a worker thread to release later. If thread
+        local storage isn't disabled in this case, the worker thread won't see
+        the token set by the thread that acquired the lock. Our assumption
+        is that these cases aren't common and as such default to using
+        thread local storage."""
+        if lock_class is None:
+            lock_class = Lock
+        return lock_class(
+            self,
+            name,
+            timeout=timeout,
+            sleep=sleep,
+            blocking_timeout=blocking_timeout,
+            thread_local=thread_local,
+        )
+
 
 class ClusterNode:
     """

redis/asyncio/lock.py

@@ -7,7 +7,7 @@
 from redis.exceptions import LockError, LockNotOwnedError
 
 if TYPE_CHECKING:
-    from redis.asyncio import Redis
+    from redis.asyncio import Redis, RedisCluster
 
 
 class Lock:
@@ -77,7 +77,7 @@ class Lock:
 
     def __init__(
         self,
-        redis: "Redis",
+        redis: Union["Redis", "RedisCluster"],
         name: Union[str, bytes, memoryview],
         timeout: Optional[float] = None,
         sleep: float = 0.1,
@@ -189,7 +189,11 @@ async def acquire(
         if token is None:
             token = uuid.uuid1().hex.encode()
         else:
-            encoder = self.redis.connection_pool.get_encoder()
+            try:
+                encoder = self.redis.connection_pool.get_encoder()
+            except AttributeError:
+                # Cluster
+                encoder = self.redis.get_encoder()
             token = encoder.encode(token)
         if blocking is None:
             blocking = self.blocking
@@ -233,7 +237,11 @@ async def owned(self) -> bool:
         # need to always compare bytes to bytes
         # TODO: this can be simplified when the context manager is finished
         if stored_token and not isinstance(stored_token, bytes):
-            encoder = self.redis.connection_pool.get_encoder()
+            try:
+                encoder = self.redis.connection_pool.get_encoder()
+            except AttributeError:
+                # Cluster
+                encoder = self.redis.get_encoder()
             stored_token = encoder.encode(stored_token)
         return self.local.token is not None and stored_token == self.local.token
 

redis/commands/core.py

@@ -4930,7 +4930,11 @@ def __init__(self, registered_client: "Redis", script: ScriptTextT):
         if isinstance(script, str):
             # We need the encoding from the client in order to generate an
             # accurate byte representation of the script
-            encoder = registered_client.connection_pool.get_encoder()
+            try:
+                encoder = registered_client.connection_pool.get_encoder()
+            except AttributeError:
+                # Cluster
+                encoder = registered_client.get_encoder()
             script = encoder.encode(script)
         self.sha = hashlib.sha1(script).hexdigest()
 
@@ -4975,7 +4979,11 @@ def __init__(self, registered_client: "AsyncRedis", script: ScriptTextT):
         if isinstance(script, str):
             # We need the encoding from the client in order to generate an
             # accurate byte representation of the script
-            encoder = registered_client.connection_pool.get_encoder()
+            try:
+                encoder = registered_client.connection_pool.get_encoder()
+            except AttributeError:
+                # Cluster
+                encoder = registered_client.get_encoder()
             script = encoder.encode(script)
         self.sha = hashlib.sha1(script).hexdigest()
 

tests/test_asyncio/test_lock.py

@@ -7,7 +7,6 @@
 from redis.exceptions import LockError, LockNotOwnedError
 
 
-@pytest.mark.onlynoncluster
 class TestLock:
     @pytest_asyncio.fixture()
     async def r_decoded(self, create_redis):