ecs-logging-java | Centralized logging for Java applications

I thought I had documented this but the closest I could come is in Log4j-Audit's RequestContext.. I guess I need to add a new entry to my blog. The short answer to this is that you use Log4j 2's ThreadContextMap. First, when a user logs in create a session map that contains the data you want to capture in each request, such as the user's ip address and loginId. Then create servlet Filter or Spring Interceptor to add that data as well as a unique request id to Log4j 2's Thread Context Map.

All Leg Events will include the data in the ThreadContext. The ECSLayout automatically includes all the fields in the ThreadContextMap.

Lastly, you need to propagate the RequestContext to downstream services. You do that by creating a Spring Interceptor that gets wired into the RestTemplate which converts the RequestContext fields into HTTP headers. The downstream service then has a Filter or Spring Interceptor that converts the headers back into RequestContext attributes. Log4j Audit (referenced above) has examples and implementations of all these components.

I should add that the method described above does not implement tracing as described by the WSC Trace Context spec so it is also not compatible with Elasticsearch's distributed tracing support. It is worth noting however, that if one were to include Elasticsearch's distributed tracing support along with New Relic's distributed tracing support they would step on each other.