[CAMEL-16178] Enrich with REST+netty hangs when connection is closed without response

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.4.5, 3.7.2
• Fix Version/s: 3.7.3, 3.9.0
• Estimated Complexity: Unknown
• Assignee: Unassigned
• Reporter: Krzysztof Jamróz
• Created: 10/Feb/21 15:53
• Updated: 18/Feb/21 16:08
• Resolved: 18/Feb/21 16:08

Description

Enricher hangs when used with REST endpoint utilizing netty when there is no response from the server but the server immediately closes the connection. In such case read timeout is ignored as connection is already closed.
 
The reason of this behavior is that org.apache.camel.component.netty.handlers.ClientChannelHandler.channelInactive contains following conditions for callback invocation when there was no response:

configuration.isSync() && !doneUoW && !messageReceived && !exceptionHandled

where

doneUoW = exchange.getUnitOfWork() == null

It works as expected when initially there had been UoW in Exchange (this is the case when using to). However, enricher by default (and by design) clears UoW for exchange it creates and this breaks above check.

Setting shareUnitOfWork for enrich works around the problem.

Issue Links

• is blocked by: CAMEL-16227 Netty with reuseChannel=true invokes wrong callback
• is caused by: CAMEL-9527 camel-netty4 - Should not log stacktrace when client has received reply
• is related to: CAMEL-7500 Concurrent modification of exchange during retry after netty TCP failure leads to futher processing of failed messages
• links to: GitHub Pull Request #5093