Fix missing attributes in RedisCluster spans

[a-cid]

Description

Modifies _set_connection_attributes to handle conn being an instance of redis.cluster.RedisCluster.

Fixes #2505

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• Unit test.

Does This PR Require a Core Repo Change?

• No.

Checklist:

See contributing.md for styleguide, changelog guidelines, and more.

• Followed the style guidelines of this project
• Changelogs have been updated
• Unit tests have been added
• Documentation has been updated

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: a-cid / name: Auster Cid (f3024bc, 65e2c64, 7802ade, 8ff71aa, 0c97cdf, a0f908a, f5c4bf4, 848cc51, ac8cc13)
• ✅ login: xrmx / name: Riccardo Magliocchetti (045c9c6, 5e71011)

[xrmx]

Thanks for the PR, I think this is missing a test to check it's working :)

[a-cid]

@xrmx

I've added the requested test

Have to admit that mocking RedisCluster was a challenge.
Full disclosure, I ended up copying some code from https://github.com/redis/redis-py/blob/master/tests/test_cluster.py
Hope that's not a problem.

[xrmx]

@a-cid please take a look at failing docker tests

[a-cid]

@xrmx

Fixed

[lzchen]

Can we not access connection_kwargs directly from the NodeManager or is this a different set of kwargs?

[a-cid]

Apologies for the delay, I've been a bit busy with work.

The call to cleanup_kwargs removes host and port from the kwargs passed to the NodeManager, so we have to get them from the nodes.