[RATIS-1834] ServerRequestStreamObserver is not properly closed

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.5.0
• Fix Version/s: 3.0.0, 2.5.1
• Component/s: gRPC, snapshot
• Assignee: Tsz-wo Sze
• Reporter: Song Ziyang
• Created: 17/Apr/23 13:03
• Updated: 27/Apr/23 18:14
• Resolved: 26/Apr/23 15:14

Description

ServerRequestStreamObserver is not properly closed.

After receiving the COMPLETE flag from the client side, it immediately closes the stream and also sends a COMPLETE flag to the client. see [1]. However, the server observer may not finish processing requests in onNext, therefore, the replies of these unfinished requests are lost.

If the client side waits on receiving all replies[2], this situation will become a deadlock.

[1] https://github.com/apache/ratis/blob/master/ratis-grpc/src/main/java/org/apache/ratis/grpc/server/GrpcServerProtocolService.java#L143-L147
[2] https://github.com/apache/ratis/blob/master/ratis-grpc/src/main/java/org/apache/ratis/grpc/server/GrpcLogAppender.java#L624

Issue Links

• links to: GitHub Pull Request #876