Re: [Hawkular-dev] [hawkular-apm] tracing async operations

Hi John If I put things in OpenTracing terms, each unit of work we want to measure is a Span, where work performed in the scope of one Span, is created as a child of that Span - so building up a tree structure. So this is how units of work, whether sync or async, get represented. So the issue is, how we identify the start and end of a Span, when they are not necessarily occurring within the same thread. And secondly, when a child activity is spawned, that is not in the same thread as its parent, how that child Span becomes associated with its parent. The piece of code you reference is part of the original java agent, and it relies on ThreadLocal as a way to track activity within threads - but to support async behaviour, the agent also enables the trace sessions/context to be propagated across threads, using context relevant ids. If explicitly instrumenting code with the OpenTracing API, async behaviour can be monitored by simply passing around the Span objects. Let me know if you need further information in any particular area. Regards Gary ----- Original Message -----