Failover handling improvements for RedisCluster and Async RedisCluster (#2377)

* Cluster&AsyncCluster: Removed handling of timeouts/connection errors within the cluster loop, fixed "cannot pickle '_thread.lock' object" bug, added client's side failover handling improvements

* Fixed linters

* Type fixes

* Added to CHANGES

* Added getter and setter for the client's retry object and added more tests

* Fixed linters

* Fixed test

* Fixed test_client_kill test

* Changed get_default_backoff to default_backoff, removed retry_on_error and connection_error_retry_attempts from RedisCluster, default retry changed to no retries

* Fixing linters

* Reverting deletion of connection_error_retry_attempts to maintain backward compatibility

* Updating retry object for existing and new connections

* Changed the default value of reinitialize_steps from 10 to 5

* fix review comments

Co-authored-by: Chayim <chayim@users.noreply.github.com>
Co-authored-by: dvora-h <dvora.heller@redis.com>
Co-authored-by: dvora-h <67596500+dvora-h@users.noreply.github.com>

1 files changed, 13 insertions, 4 deletions

diff --git a/redis/backoff.py b/redis/backoff.py
index 5ccdb91..c62e760 100644
--- a/redis/backoff.py
+++ b/redis/backoff.py
@@ -1,6 +1,11 @@
 import random
 from abc import ABC, abstractmethod
 
+# Maximum backoff between each retry in seconds
+DEFAULT_CAP = 0.512
+# Minimum backoff between each retry in seconds
+DEFAULT_BASE = 0.008
+
 
 class AbstractBackoff(ABC):
     """Backoff interface"""
@@ -40,7 +45,7 @@ class NoBackoff(ConstantBackoff):
 class ExponentialBackoff(AbstractBackoff):
     """Exponential backoff upon failure"""
 
-    def __init__(self, cap, base):
+    def __init__(self, cap=DEFAULT_CAP, base=DEFAULT_BASE):
         """
         `cap`: maximum backoff time in seconds
         `base`: base backoff time in seconds
@@ -55,7 +60,7 @@ class ExponentialBackoff(AbstractBackoff):
 class FullJitterBackoff(AbstractBackoff):
     """Full jitter backoff upon failure"""
 
-    def __init__(self, cap, base):
+    def __init__(self, cap=DEFAULT_CAP, base=DEFAULT_BASE):
         """
         `cap`: maximum backoff time in seconds
         `base`: base backoff time in seconds
@@ -70,7 +75,7 @@ class FullJitterBackoff(AbstractBackoff):
 class EqualJitterBackoff(AbstractBackoff):
     """Equal jitter backoff upon failure"""
 
-    def __init__(self, cap, base):
+    def __init__(self, cap=DEFAULT_CAP, base=DEFAULT_BASE):
         """
         `cap`: maximum backoff time in seconds
         `base`: base backoff time in seconds
@@ -86,7 +91,7 @@ class EqualJitterBackoff(AbstractBackoff):
 class DecorrelatedJitterBackoff(AbstractBackoff):
     """Decorrelated jitter backoff upon failure"""
 
-    def __init__(self, cap, base):
+    def __init__(self, cap=DEFAULT_CAP, base=DEFAULT_BASE):
         """
         `cap`: maximum backoff time in seconds
         `base`: base backoff time in seconds
@@ -103,3 +108,7 @@ class DecorrelatedJitterBackoff(AbstractBackoff):
         temp = random.uniform(self._base, max_backoff)
         self._previous_backoff = min(self._cap, temp)
         return self._previous_backoff
+
+
+def default_backoff():
+    return EqualJitterBackoff()