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Fix sentinel mode read-write separation #749

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merged 5 commits into from
Oct 20, 2024

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JackiLin
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@JackiLin JackiLin commented Sep 6, 2024

When I attempted to set up read-write separation in Sentinel mode by configuring redis://redis-master/db?is_master=0, I noticed that both read and write requests were still being directed to the master node, without any separation. After reviewing and debugging the source code, I found that the issue was due to redis-py being unable to correctly parse the is_master parameter, and there was also an error in how the project handled is_master. The pool.is_master was only set to False after retrieving the redis.sentinel.SentinelConnectionPool object from redis-py, which resulted in the system supposedly using the slave node, but actually using the master node.
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codecov bot commented Sep 6, 2024

Codecov Report

Attention: Patch coverage is 71.42857% with 4 lines in your changes missing coverage. Please review.

Project coverage is 63.2%. Comparing base (f30d34c) to head (f23b06d).
Report is 7 commits behind head on master.

Files with missing lines Patch % Lines
django_redis/pool.py 66.7% 4 Missing ⚠️
Additional details and impacted files
@@           Coverage Diff            @@
##           master    #749     +/-   ##
========================================
- Coverage    63.2%   63.2%   -0.0%     
========================================
  Files          43      43             
  Lines        3223    3231      +8     
  Branches      244     244             
========================================
+ Hits         2034    2039      +5     
- Misses       1172    1175      +3     
  Partials       17      17             
Flag Coverage Δ
mypy 37.9% <21.5%> (-<0.1%) ⬇️
tests 90.3% <80.0%> (-<0.1%) ⬇️

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LGTM!

# so it doesn't interfere with the SentinelConnectionPool constructor
if "is_master" in query_params:
del query_params["is_master"]
new_query = urlencode(query_params, doseq=True)
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why do you need this if you deleted the key from the original query_params variable?

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If this parameter is not deleted, it cannot be correctly parsed as bool type in redis-py, but as str type. This will cause it to use the master node for reading and writing even if is_master=0 is set.

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yeah, sure, my bad

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please merge master into your branch and solve conflicts then

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I have merged and resolved the conflicts

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LGTM!

@WisdomPill WisdomPill merged commit f98dcce into jazzband:master Oct 20, 2024
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2 participants