fix(proxy): disable buffering for sandbox streams

[josh-cow]

Patch for nginx config:

• Adds proxy_buffering off;
• Adds proxy_request_buffering off;
• Applies to both HTTP and HTTPS CubeProxy sandbox locations in CubeProxy/nginx.conf

Interactive envd Connect streams (PTY) need chunks flushed immediately. With CubeProxy’s global proxy_buffering on, long-lived PTY streams can receive input but not deliver output
promptly.

Validated:

• nginx -t inside the running cube-proxy container passed.
• After reload, direct envd Process/Start returned 200 and streamed the start frame immediately.

[kinwin-ustc]

CubeSandbox is not just for envd, there are also scenarios where buffers are needed, and perhaps we need to clearly distinguish which requests require buffers and which are not

[staryxchen]

Thanks for the contribution @josh-cow. proxy_buffering and proxy_request_buffering are two global directives that proxy all sandbox traffic, not just envd streams. So I suggesting fixing this at the response level via setting X-Accel-Buffering: no from envd, or by adding a dedicated streaming-only location.

[josh-cow]

Thanks for the contribution @josh-cow. proxy_buffering and proxy_request_buffering are two global directives that proxy all sandbox traffic, not just envd streams. So I suggesting fixing this at the response level via setting X-Accel-Buffering: no from envd, or by adding a dedicated streaming-only location.

@kinwin-ustc @staryxchen
Make sense. are you on the plan ? Or may I draft the changes? Thanks.

[kinwin-ustc]

I think you can continue to modify in this direction

[staryxchen]

Thanks for the contribution @josh-cow. proxy_buffering and proxy_request_buffering are two global directives that proxy all sandbox traffic, not just envd streams. So I suggesting fixing this at the response level via setting X-Accel-Buffering: no from envd, or by adding a dedicated streaming-only location.

@kinwin-ustc @staryxchen Make sense. are you on the plan ? Or may I draft the changes? Thanks.

Hi @josh-cow, I have raised an issue (e2b-dev/infra#2707) to envd, but haven’t received a response yet. So I think you can working on the Cube side (adding a dedicated streaming-only location) first to workaround.