Client Acknowledgement for GraphQL Subscriptions Event

[KelltonTechSolutions]

Hello Everyone,

We are currently in the process of implementing GraphQL subscriptions to push critical events to clients. Ensuring reliable delivery is essential, and to achieve this, we intend to track successful event delivery by receiving acknowledgment (ACK) messages from clients. This acknowledgment mechanism will also allow us to safely commit the corresponding events in the source system (Kafka).

Upon reviewing the documentation and community forums, it appears that the graphql-ws library does not natively support ACK handling. However, I came across a suggested approach that involves opening a socket listener to capture and process ACK messages before invoking useServer.

I attempted this implementation and observed that while ACK messages are received, the WebSocket connection is unexpectedly closing afterward.

Would you happen to have any reference implementations that demonstrate a working acknowledgment mechanism? Alternatively, any guidance or best practices for implementing this pattern would be greatly appreciated.

[enisdenjo]

Hey there, what was the suggested approach you came across? Is the "ws server and client usage with subscription acknowledgment" recipe something you can find useful?

[KelltonTechSolutions]

Thank you, @enisdenjo.

Based on my understanding of the "WS server and client usage with subscription acknowledgment" documentation, the mechanism is intended to inform the client that the subscription has been successfully established.

However, my requirement is slightly different:

1. The subscription server publishes events with a unique delivery token.
2. Upon receiving an event, the client should send an acknowledgment containing the corresponding delivery token.
3. This delivery token is then used by the server to commit the event.

Essentially, I am looking for a way to implement a positive acknowledgment mechanism where the client explicitly confirms receipt of each event to the server.