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Redlock and AIORedlock now support infinite lock extensions #792

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Redlock and AIORedlock now support infinite lock extensions #792

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de60cc3
Redlock class now supports infinite lock extensions
aabmets Sep 15, 2025
2d09456
Fixed syntax error in extend method
aabmets Sep 15, 2025
f34adf6
Re-added empty line after parameter validations
aabmets Sep 15, 2025
26f41f5
AIORedlock class now supports infinite lock extensions
aabmets Sep 15, 2025
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22 changes: 15 additions & 7 deletions pottery/aioredlock.py
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Original file line number Diff line number Diff line change
Expand Up @@ -49,6 +49,7 @@
from typing import ClassVar
from typing import Iterable
from typing import Type
from typing import Union

from redis import RedisError
from redis.asyncio import Redis as AIORedis
Expand Down Expand Up @@ -150,15 +151,15 @@ class AIORedlock(Scripts, AIOPrimitive):
_AUTO_RELEASE_TIME: ClassVar[float] = Redlock._AUTO_RELEASE_TIME
_CLOCK_DRIFT_FACTOR: ClassVar[float] = Redlock._CLOCK_DRIFT_FACTOR
_RETRY_DELAY: ClassVar[float] = Redlock._RETRY_DELAY
_NUM_EXTENSIONS: ClassVar[int] = Redlock._NUM_EXTENSIONS
_NUM_EXTENSIONS: ClassVar[Union[int, float]] = Redlock._NUM_EXTENSIONS

def __init__(self,
*,
key: str,
masters: Iterable[AIORedis],
raise_on_redis_errors: bool = False,
auto_release_time: float = _AUTO_RELEASE_TIME,
num_extensions: int = _NUM_EXTENSIONS,
num_extensions: Union[int, float] = _NUM_EXTENSIONS,
context_manager_blocking: bool = True,
context_manager_timeout: float = -1,
) -> None:
Expand All @@ -173,8 +174,8 @@ def __init__(self,
auto_release_time -- the timeout in seconds by which to
automatically release this AIORedlock, unless it's already been
released
num_extensions -- the number of times that this AIORedlock's lease
can be extended
num_extensions -- the number of times that this Redlock's lease can be extended.
Value can be either a positive integer or float infinity (math.inf)
context_manager_blocking -- when using this AIORedlock as a context
manager, whether to block when acquiring
context_manager_timeout -- if context_manager_blocking, how long to
Expand All @@ -183,7 +184,9 @@ def __init__(self,
'''
if not context_manager_blocking and context_manager_timeout != -1:
raise ValueError("can't specify a timeout for a non-blocking call")

if num_extensions < 0 or (isinstance(num_extensions, float) and not math.isinf(num_extensions)):
raise ValueError("num_extensions must be either a positive integer or float infinity")

super().__init__(
key=key,
masters=masters,
Expand All @@ -196,6 +199,10 @@ def __init__(self,
self._uuid = ''
self._extension_num = 0

@property
def limited_extensions(self) -> bool:
return not math.isinf(self.num_extensions)

# Preserve the Open-Closed Principle with name mangling.
# https://youtu.be/miGolgp9xq8?t=2086
# https://stackoverflow.com/a/38534939
Expand Down Expand Up @@ -450,7 +457,7 @@ async def extend(self,
9
10
'''
if self._extension_num >= self.num_extensions:
if self.limited_extensions and self._extension_num >= self.num_extensions:
raise TooManyExtensions(self.key, self.masters)

num_masters_extended, redis_errors = 0, []
Expand All @@ -466,7 +473,8 @@ async def extend(self,
error.__class__.__qualname__,
)
if num_masters_extended > len(self.masters) // 2:
self._extension_num += 1
if self.limited_extensions:
self._extension_num += 1
return

self._check_enough_masters_up(raise_on_redis_errors, redis_errors)
Expand Down
28 changes: 17 additions & 11 deletions pottery/redlock.py
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,7 @@
from typing import Literal
from typing import Tuple
from typing import Type
from typing import Union
from typing import cast
from typing import overload

Expand Down Expand Up @@ -229,15 +230,15 @@ class Redlock(Scripts, Primitive):
_AUTO_RELEASE_TIME: ClassVar[float] = 10
_CLOCK_DRIFT_FACTOR: ClassVar[float] = 0.01
_RETRY_DELAY: ClassVar[float] = .2
_NUM_EXTENSIONS: ClassVar[int] = 3
_NUM_EXTENSIONS: ClassVar[Union[int, float]] = 3

def __init__(self,
*,
key: str,
masters: Iterable[Redis] = frozenset(),
raise_on_redis_errors: bool = False,
auto_release_time: float = _AUTO_RELEASE_TIME,
num_extensions: int = _NUM_EXTENSIONS,
num_extensions: Union[int, float] = _NUM_EXTENSIONS,
context_manager_blocking: bool = True,
context_manager_timeout: float = -1,
) -> None:
Expand All @@ -252,8 +253,8 @@ def __init__(self,
auto_release_time -- the timeout in seconds by which to
automatically release this Redlock, unless it's already been
released
num_extensions -- the number of times that this Redlock's lease can
be extended
num_extensions -- the number of times that this Redlock's lease can be extended.
Value can be either a positive integer or float infinity (math.inf)
context_manager_blocking -- when using this Redlock as a context
manager, whether to block when acquiring
context_manager_timeout -- if context_manager_blocking, how long to
Expand All @@ -262,7 +263,9 @@ def __init__(self,
'''
if not context_manager_blocking and context_manager_timeout != -1:
raise ValueError("can't specify a timeout for a non-blocking call")

if num_extensions < 0 or (isinstance(num_extensions, float) and not math.isinf(num_extensions)):
raise ValueError("num_extensions must be either a positive integer or float infinity")

super().__init__(
key=key,
masters=masters,
Expand All @@ -275,6 +278,10 @@ def __init__(self,
self._uuid = ''
self._extension_num = 0

@property
def limited_extensions(self) -> bool:
return not math.isinf(self.num_extensions)

def __acquire_master(self, master: Redis) -> bool:
acquired = master.set(
self.key,
Expand Down Expand Up @@ -520,7 +527,7 @@ def extend(self, *, raise_on_redis_errors: bool | None = None) -> None:
True
>>> printer_lock.release()
'''
if self._extension_num >= self.num_extensions:
if self.limited_extensions and self._extension_num >= self.num_extensions:
raise TooManyExtensions(self.key, self.masters)

with BailOutExecutor() as executor:
Expand All @@ -542,7 +549,8 @@ def extend(self, *, raise_on_redis_errors: bool | None = None) -> None:
)
else:
if num_masters_extended > len(self.masters) // 2:
self._extension_num += 1
if self.limited_extensions:
self._extension_num += 1
return

self._check_enough_masters_up(raise_on_redis_errors, redis_errors)
Expand Down Expand Up @@ -699,11 +707,9 @@ def synchronize(*,
exception when too many Redis masters throw errors
auto_release_time -- the timeout in seconds by which to automatically
release this Redlock, unless it's already been released
num_extensions -- the number of times that this Redlock's lease can be
extended
context_manager_blocking -- when using this Redlock as a context
blocking -- when using this Redlock as a context
manager, whether to block when acquiring
context_manager_timeout -- if context_manager_blocking, how long to wait
timeout -- if context_manager_blocking, how long to wait
when acquiring before giving up and raising the QuorumNotAchieved
exception

Expand Down