As we are turning redisless ray by default, dashboard doesn't need to talk with redis anymore. Instead it should talk with gcs and gcs can talk with redis.
This is the second part of https://docs.google.com/document/d/12qP3x5uaqZSKS-A_kK0ylPOp0E02_l-deAbmm8YtdFw/edit#. After this PR, dashboard agents will fully work with minimal ray installation.
Note that this PR requires to introduce "aioredis", "frozenlist", and "aiosignal" to the minimal installation. These dependencies are very small (or will be removed soon), and including them to minimal makes thing very easy. Please see the below for the reasoning.
- Tolerate GRPC deadline exceeded and transient failures in Python GCS AIO subscribers, which becomes consistent with Python GCS synchronous subscribers.
- Tolerate any exception in dashboard for subscribing to logs and error info, which becomes consistent with how dashboard handles GRPC errors for obtaining node stats.
Dashboard contains resource reporter and actor subscribers. Dashboard agent has resource report publisher. So GCS pubsub needs to support these channel types.
Also refactor GCS AIO subscribers to have each subscriber per channel. This matches the API of GCS sync subscribers, and make subscribing with multiple channels easier.
Using Ray pubsub for publishing and subscribing logs via GCS, from Python worker, log importer, dashboard and unit tests.
This change is guarded behind the RAY_gcs_grpc_based_pubsub feature flag.
## Why are these changes needed?
Publisher and subscriber for logs, in driver, dashboard and tests are refactored to make it easier to support using Ray pubsub for logs. Actual support of Ray pubsub for logs will be added later in #20492.
This PR does not intend to introduce any behavior change.
## Related issue number
## Why are these changes needed?
This change adds Python publisher and subscriber in `gcs_utils.py`, and GRPC handler on GCS for publishing iva GCS. Error info is migrated to use the GCS-based pubsub, if feature flag `RAY_gcs_grpc_based_pubsub=true`.
Also, add a `--gcs-address` flag to some Python processes. It is not set anywhere yet, but will be set aftering Redis-less bootstrapping work.
Unit tests are added for the Python publisher and subscriber. Migrated error info publishers and subscribers are tested with existing unit tests, e.g. tests calling `ray._private.test_utils.get_error_message()` to ensure error info is published.
GCS based pubsub has gaps in handling deadline, cancelled requests and GCS restarts. So 3 more unit tests are disabled in the `HA GCS` mode. They will be addressed in a separate change.
## Related issue number
## Why are these changes needed?
This is part of redis removal project. In this PR all direct usage of redis got removed except function table.
Function table will be migrated in the next PR
## Related issue number
#19443
