Implement Handling for GROUP_DROPPED Messages

[OkutaniDaichi0106]

Implement Handling for GROUP_DROPPED Messages

Description

Implement logic to handle GROUP_DROPPED messages in the subscription process. This feature will ensure that the system properly manages cases where a Group Stream is reset or cannot be fully delivered.

Background

The protocol specifies that:

1. The publisher MUST send a GROUP_DROPPED message if a Group Stream is reset.
2. The subscriber SHOULD properly handle GROUP_DROPPED messages to maintain consistency and determine when a subscription can be closed.

Handling these messages is crucial to:

• Inform the subscriber of incomplete Group Streams.
• Allow the subscriber to close subscriptions cleanly.
• Ensure data integrity in scenarios involving dropped or reset streams.

Acceptance Criteria

• Publisher sends GROUP_DROPPED messages whenever a Group Stream is reset.
• Subscriber identifies and processes GROUP_DROPPED messages correctly.
• Tests to verify that GROUP_DROPPED messages trigger appropriate behaviors (e.g., logging, cleanup, retries).
• Documentation updated to reflect how GROUP_DROPPED messages are handled.

Tasks

1. Publisher Implementation:

   • Add logic to detect Group Stream resets and send GROUP_DROPPED messages.
   • Ensure compliance with protocol requirements (e.g., MUST/MAY rules).

2. Subscriber Implementation:

   • Add handling for GROUP_DROPPED messages.
   • Implement optional behaviors (e.g., retries, state updates, or ignoring non-critical groups).

3. Testing:

   • Create unit and integration tests to cover scenarios where GROUP_DROPPED messages are used.
   • Validate that subscriptions are closed correctly when all messages are received.

4. Documentation:

   • Update protocol handling guides with examples of GROUP_DROPPED usage.
   • Add developer notes about edge cases (e.g., frequent resets, long-running streams).

Additional Notes

• Ensure backward compatibility with existing implementations.
• Consider performance implications of additional message handling in high-load scenarios.

References

• Moq Transport - Group Drop

Priority

High

[OkutaniDaichi0106]

I have already implemented the GROUP_DROPPED message with Encode and Decode methods in the internal/message/group_drop.go file.