SETNX with TTL

[vskr]

Is it possible to do a atomic SETNX with TTL. I use redis as distributed key value store, and am looking to simulate lock -> update -> release pattern on redis.

Since SETNX doesn't take expiration time, if the thread which obtains lock dies subsequent SETNX's are always false

[andymccurdy]

If you're using Redis server 2.6.12 or greater and redis-py 2.7.4 or greater, you can pass additional arguments to the SET command.

r = redis.StrictRedis(...)
r.set('my-key', 'my-value', nx=True, ex=10)  # 10 second expiration, note you can also use `px` for millisecond resolution

You could also do this with LUA scripting or with a pipeline+watch command.

[duhaime]

In case others want to set up a lock pattern in Redis, redlock-py offers an implementation of the redlock algorithm that the Redis docs recommend for this purpose.

[kingname]

If you're using Redis server 2.6.12 or greater and redis-py 2.7.4 or greater, you can pass additional arguments to the SET command.

r = redis.StrictRedis(...)
r.set('my-key', 'my-value', nx=True, ex=10)  # 10 second expiration, note you can also use `px` for millisecond resolution

You could also do this with LUA scripting or with a pipeline+watch command.

you can not use r.set with nx=True as the replacement of r.setnx，because r.setnx will return True/False to show if this key exists already, but r.set always return None.

[patrick91]

@kingname I know this is an old issue, but this seems to be working as expected now :D