Fix a bug where closing a websocket session could send a RST_STREAM frame

[jrhee17]

Motivation:

Currently, once an HttpRequest and HttpResponse is completed, the underlying HTTP2 stream is cancelled using a RST_STREAM.
This makes sense for normal HTTP constructs since it indicates that we are no longer interested in the request, and we would like to release resources associated with it.

However, some protocols such as WebSockets implement their own graceful shutdown procedure.

In detail, Armeria's HttpRequest, HttpResponse implements WebSocket graceful shutdown and the reactive stream implementation is closed when a CLOSE frame is both sent and received.
However, although the websocket session is completed, the underlying HTTP2 stream may not necessarily be complete.
Protocol-wise, there is an inherent discrepancy between websocket session completion and HTTP2 stream completion.

The current implementation defaults to sending a RST_STREAM immediately once the corresponding HttpRequest and HttpResponse. For websockets, I propose that a delay is given so that the remote has a chance to end the stream.

Assuming that we will tie the lifecycle of inbound WebSockets with outbound WebSockets (so sending a close frame also closes the inbound) in #6357 , this option can be thought of similar to netty's forceCloseTimeoutMillis option. (which acts as a timeout since sending the CLOSE frame)

Modifications:

• Added a closeHttp2StreamDelayMillis option to ServiceConfig and relevant implementations
• WebSocketService sets a closeHttp2StreamDelayMillis of 10 seconds by default
• HttpServerHandler decides when to send a RST_STREAM based on the closeHttp2StreamDelayMillis
• Added Http2StreamLifecycleHandler which maintains the lifecycle of reset futures. This ensures that scheduled futures aren't leaked for servers with high throughput.
  • Every time a request/response is closed but the corresponding stream is alive, maybeResetStream is called.
  • Every time a stream is closed, notifyStreamClosed is called to clean up possibly scheduled futures.

Result:

• Users can set a timeout for closing a websocket session
• Fix a bug where closing a websocket session could send a RST_STREAM frame

[codecov]

Codecov Report

❌ Patch coverage is 72.88136% with 16 lines in your changes missing coverage. Please review.
✅ Project coverage is 74.09%. Comparing base (8150425) to head (16fa03e).
⚠️ Report is 179 commits behind head on main.

Files with missing lines	Patch %	Lines
...rp/armeria/server/Http2StreamLifecycleHandler.java	65.78%	8 Missing and 5 partials ⚠️
...va/com/linecorp/armeria/server/ServiceOptions.java	50.00%	3 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #6375      +/-   ##
============================================
- Coverage     74.46%   74.09%   -0.37%     
- Complexity    22234    22984     +750     
============================================
  Files          1963     2061      +98     
  Lines         82437    86105    +3668     
  Branches      10764    11306     +542     
============================================
+ Hits          61385    63802    +2417     
- Misses        15918    16893     +975     
- Partials       5134     5410     +276     

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[github-actions]

🔍 Build Scan® (commit: 16fa03e)

Job name	Status	Build Scan®
build-ubicloud-standard-16-jdk-8	✅	https://ge.armeria.dev/s/5yxvrrtagw42c
build-ubicloud-standard-16-jdk-21-snapshot-blockhound	✅	https://ge.armeria.dev/s/ij3ostxyao2bq
build-ubicloud-standard-16-jdk-17-min-java-17-coverage	✅	https://ge.armeria.dev/s/3ts6yu5lhip5u
build-ubicloud-standard-16-jdk-17-min-java-11	✅	https://ge.armeria.dev/s/2t6zfwjmkzqsm
build-ubicloud-standard-16-jdk-17-leak	✅	https://ge.armeria.dev/s/uckd44rgdauxi
build-ubicloud-standard-16-jdk-11	✅	https://ge.armeria.dev/s/3x7sgsbnf2ada
build-macos-latest-jdk-21	✅	https://ge.armeria.dev/s/dnzbom3ll7csm

[minwoox]

Looks nice. 👍

[minwoox]

Could you put this value in WebSocketUtil?
Could you update the Javadoc?

[ikhoon]

👍 👍