Unified streaming endpoint

[begelundmuller]

Implements a unified streaming endpoint that exposes the runtime server's streaming RPCs over a single SSE endpoint with the ability to serve multiple streams on a single connection.

This can be used to reduce the number of concurrent streaming connections, which may help alleviate blocked connections due to browsers limiting unsecured/localhost connections to 6 per origin.

Example:

> curl http://localhost:9009/v1/instances/default/sse?events=file,resource,log
event: file
data: {"event":"FILE_EVENT_WRITE",...}

event: resource
data: {"event":"RESOURCE_EVENT_WRITE",...}

event: resource
data: {"event":"RESOURCE_EVENT_WRITE",...}

event: log
data: {"log":{"level":"LOG_LEVEL_INFO",...}}

...

Details:

• The unified endpoint is hosted at <runtime-host>/v1/<instance-id>/sse
• It supports the following query parameters:
  • events: comma-separated list of event types to subscribe to. Supported values are: file, resource, log.
  • files_replay: maps to the underlying WatchFilesRequest.Replay
  • resources_kind: maps to the underlying WatchResourcesRequest.Kind
  • resources_replay: maps to the underlying WatchResourcesRequest.Replay
  • logs_replay: maps to the underlying WatchLogsRequest.Replay
  • logs_replay_limit: maps to the underlying WatchLogsRequest.ReplayLimit
  • logs_level: maps to the underlying WatchLogsRequest.Level

Closes https://linear.app/rilldata/issue/PLAT-356/unified-endpoint-for-streaming-apis

Checklist:

• Covered by tests
• Ran it and it works as intended
• Reviewed the diff before requesting a review
• Checked for unhandled edge cases
• Linked the issues it closes
• Checked if the docs need to be updated. If so, create a separate Linear DOCS issue
• Intend to cherry-pick into the release branch
• I'm proud of this work!

[pjain1]

is this by convention that logs_ is prefixed to all api param names?

[begelundmuller]

Yes, all the params that go to WatchLogsRequest have logs_ prefix, all the params for WatchFilesRequest have files_ prefix, etc.