reqAttribute() misses value in access log after timeout

[yongsrepos]

Hello,
Our Kotlin service uses Logback 1.2.11. In the log format of our access log, we use "%reqAttribute(myAttr)" to retrieve the attribute "myAttr", which we set in the request context via a container request filter. In normal cases, this attribute is present in the logs. But in below case, it is missing:

• a client sends a request to our service, which further requests an upstream service. When the request towards the upstream service from our service encounters timeout, "%reqAttribute(myAttr)" can't resolve any value in the access log entry from the client.

Our service uses Jetty as the container. The timeout is thrown by org.eclipse.jetty.server.HttpChannel#handleException.

Any hint will be much appreciated. Thanks!
Cheers,
Yong