KEP-5116: Add KEP (Streaming response encoding)

[serathius]

#5116

/assign @deads2k @liggitt

[deads2k]

@benluddy can you ptal?

[serathius]

/assign @jpbetz

[sftim]

Thanks. Here's a bunch of feedback.

Key points:

• let's be clear about the status of YAML and that streaming encoding to YAML won't be available
  • (does using legacy encoding to YAML provide a route for a malicious client to overload API server memory)?
• formally, the response to a list is a collection
• we style list in lower case bold in docs, and I recommend doing that here too.

[sftim]

BTW if we want to ship JSON and ProtoBuf as beta for v1.33, I don't see anything stopping us doing that and still adding streaming YAML collections before we close the KEP as Done.

[liggitt]

just an implementation note, by adding an intermediate buffer to the gzip writer wrapper, be careful not to reintroduce the issue where we don't flush headers until a non-zero number of bytes are written

https://github.com/kubernetes/kubernetes/pull/31446/files#diff-67dd9e8f3ee257072765326cb4f242852554a2c0753563fa51e292c0a63a7b94R2488

maybe the code path that hits deferredResponseWriter isn't vulnerable to that issue if it already has the single object it is serializing, but watch out for buffering a generic gzip writer wrapper if we're not sure whether or not we'll have immediate output

[liggitt]

a couple suggestions but lgtm overall

[liggitt]

/lgtm

[fuweid]

LGTM(non-binding)!

[liggitt]

this lgtm, will let @deads2k (for apimachinery) and @jpbetz (for PRR) have approval

[sftim]

/retitle KEP-5116: Add KEP (Streaming response encoding)

[wojtek-t]

this lgtm, will let @deads2k (for apimachinery) and @jpbetz (for PRR) have approval

I'm fine with this as well.

@deads2k @jpbetz - friendly ping for review

[benluddy]

LGTM. Strictly constraining the supported types keeps the special-case implementation simple, and client behavior remains unchanged.

[deads2k]

needs updates for PRR enable/disable and monitoring. The list of tests looks good. lgtm otherwise.

[serathius]

needs updates for PRR enable/disable and monitoring. The list of tests looks good. lgtm otherwise.

Fixed, thanks for review!

[deads2k]

/lgtm
/approve

[k8s-ci-robot]

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