Streamable session clean up

[He-Pin]

The current release doesn't contain any remove / clean up/ idle clean up logic, if the client never calls DELETE , then OOM.

[taobaorun]

what about to fix this by server ping
#508

[chemicL]

This is indeed a serious problem that requires addressing. Let's discuss ideas based on the comments from #508.

This can be some form of TTL and recency markers (update timestamp upon every interaction with a given session) and a scheduler task that checks that against a globally set TTL perhaps?

In the long run, this should be managed by a proper session storage, so I marked this issue with feature/session-storage label to keep in mind for the bigger theme.

[bperhaps]

I can’t think of a better approach than using TTL. Wouldn’t it be quite reasonable to simply add a feature that keeps the session alive as long as the GET SSE connection is open? If we make TTL injectable, developers could configure it according to their business needs.

On a more personal note, once SSE gets involved in streamable-http (even if it’s not a GET SSE request, such as a sampling request), the session inevitably becomes more tightly coupled to a specific server. In that case, I feel like the need for a global session storage diminishes. Is it really necessary to consider introducing a new session store? Wouldn’t it be better to keep the current architecture and just focus on handling session cleanup properly? I’m curious about your thoughts.