Support for nginx X-Accel headers

[abemusic]

Is your feature request related to a problem? Please describe.

It would be extremely beneficial for those of us using nginx in front of ld-relay to have the relay set the X-Accel-Buffering header to inform nginx that the application server is wanting to stream responses.

Describe the solution you'd like

For ld-relay routes that do streaming, it should set the header X-Accel-Buffering: no

Describe alternatives you've considered

Currently, we are disabling proxy buffering entirely for ld-relay which is not the most appropriate solution. We are considering mapping each ld-relay endpoint that supports streaming in nginx and configure those routes for streaming. Because we are simply proxying from nginx to ld-relay, it would be very nice to have the application server inform us of the streaming intent.

Additional context

https://www.nginx.com/resources/wiki/start/topics/examples/x-accel/#x-accel-buffering

[eli-darkly]

I don't suppose it's possible to configure nginx to recognize that it's a streaming response based on the content type? LaunchDarkly streaming data will always have the content type text/event-stream.

[eli-darkly]

After some digging through the docs, it seems like the answer to my question is "no"... alas. So it makes sense for Relay to add a header as you suggested. We should be able to release a new version fairly soon.

[eli-darkly]

The 5.11.0 release adds this header. Please let us know when you've had a chance to try it out.

[abemusic]

This is great! Thank you for doing that. Apologies for not getting back to you sooner, things have been a bit hectic as you can probably imagine.

I'll make some time first thing tomorrow to give the new version a spin. Thanks again!!

[abemusic]

Seems to be working great! Thank you all for the super fast turnaround! 🎉