Review Jetty ClientHttpConnector code for buffer handling on error/cancellation [SPR-17424]

[spring-projects-issues]

Rossen Stoyanchev opened SPR-17424 and commented

The request writing side is using Jetty's ContentChunk callbacks to release the input DataBuffer. However the use of flatMap from writeAndFlushWith could prefetch and requires a Flux#onDiscard hook.

---

Affects: 5.1.1

This issue is a sub-task of #21941

[spring-projects-issues]

Rossen Stoyanchev commented

Sébastien Deleuze, as far I can see for the response side, at present Jetty simply wraps a byte array along with a NoOp callback to release. That means there isn't much use in us calling succeeded() so couldn't we spare ourselves the copying and simply wrap the byte[] for now? Or if we want to support releasing, we should implement a JettyDataBuffer that works like DefaultDataBuffer and calls the ContentChunk callbacks on release.

[spring-projects-issues]

Sébastien Deleuze commented

We are simply wrapping byte array because the Jetty HttpClient uses callback.succeed() to perform 2 things: recycle the buffer and request more content (similar to RS request(1)). The fact that these 2 operations are done at the same time is a blocking issue for us when we want to create a composite buffer for example. They plan to fix this at some point, but not yet done see jetty/jetty.project#2429.

[spring-projects-issues]

Rossen Stoyanchev commented

Okay, so we can't wrap and release later. Thanks for the background.