RedisLockRegistry using PUB_SUB_LOCK does not work on AWS Elasticache Valkey Serverless

[kistlers]

In what version(s) of Spring Integration are you seeing this issue?

6.5.2

Describe the bug

RedisLockRegistry using PUB_SUB_LOCK does not work on AWS Elasticache Valkey Serverless. Internally, Elasticache uses SPUBLISH instead of PUBLISH, as documented on https://docs.aws.amazon.com/AmazonElastiCache/latest/dg/SupportedCommands.html. Check the Note in the "Pub/Sub Commands" section.
PUBLISH is used in this

spring-integration/spring-integration-redis/src/main/java/org/springframework/integration/redis/util/RedisLockRegistry.java

Line 667 in 3811244

private static final String UNLINK_UNLOCK_SCRIPT = """

script. Valkey cluster requires all sharded operations in a Lua script to hash to the same cluster slot cache. In the case of PUBLISH, this does not matter, but it does with SPUBLISH (used in Elasticache Valkey, as described).
In the script, there are three Redis operations:

• redis.call('GET', KEYS[1])
• redis.call('UNLINK', KEYS[1])
• redis.call('PUBLISH', ARGV[2], KEYS[1])
  And I, as a developer, cannot control the cluster slot cache of the third operation for each separate call of the locking operation. ARGV[2] is the unlockChannel (see

  spring-integration/spring-integration-redis/src/main/java/org/springframework/integration/redis/util/RedisLockRegistry.java

  Line 690 in 3811244

  protected boolean removeLockKeyInnerUnlink() {

  ) set globally for this RedisLockRegistry (see

  spring-integration/spring-integration-redis/src/main/java/org/springframework/integration/redis/util/RedisLockRegistry.java

  Line 206 in 3811244

  this.unLockChannelKey = registryKey + "-channel";

  ).
  I can easily control the cluster slot cache of all other operations by including a {...} in the cache, but I cannot do the same for the unlockChannelKey

To Reproduce

• Create a RedisLockRegistry with a PUB_SUB_LOCK
• Attach it to an AWS Elasticache Valkey Serverless
  • Alternatively (per my reasoning, that should work) change the PUBLISH to an SPUBLISH in the UNLINK_UNLOCK_SCRIPT and attach it to any valkey/redis.
• Run a lockRegistry.executeLocked(..) operation
• Observe the following error: Caused by: io.lettuce.core.RedisCommandExecutionException: ERR Script attempted to access keys that do not hash to the same slot script: b2dedc0ab01c17f9f20e3e6ddb62dcb6afbed0bd, on @user_script:3.

Expected behavior

PubSubLocks should also work on AWS

Sample

I have not yet prepared a sample, as it most likely requires an AWS Elasticache Valkey, which I cannot just provide to you.

[artembilan]

Just ran tests, the SPUBLISH doesn't work probably because the subscription uses SUBSCRIBE and I don't see an API in Spring Data exposed for the SSUBSCRIBE: spring-projects/spring-data-redis#3019.

I guess we are stuck here with a RedisLockType.SPIN_LOCK mode until Spring Data Redis implements SSUBSCRIBE for us.

Any other thoughts?

[kistlers]

Could we leave it at PUBLISH but append the supplied lock key to the unlockChannelKey (at least optionally, to keep it backwards-compatible for everyone)?
We could then use hash tags {...} in the lock key, and thus the key of the Publish operation to control the cluster slot cache.

I'm assuming Publish does actually care about the hash tags in the key, which I am unsure about.

[artembilan]

I'm not that good with Redis to judge what you are talking about, but contribution is welcome: https://github.com/spring-projects/spring-integration/blob/main/CONTRIBUTING.adoc

[kistlers]

I created a PR for it, see #10473. Locking and unlocking worked with the PUB_SUB_LOCK while connected to an AWS Elasticache Valkey.