Has anyone seen OTel being used well for long-running batch/async processes? Wonder how the suggestions stack up to monolith builds for Apps that take about an hour.
It doesn't matter how long things take. The best way to understand this is to realize that OTel tracing (and all other similar things) are really "fancy logging systems". Some agent code emits a log message every time something happens (e.g. batch job begins, batch job ends). Something aggregates those log messages into some place they can be coherently scanned. Then something scans those messages generating some visualization you view. Everything could be done with text messages in text files and some awk script. A tracing system is just that with batteries included and a pretty UI. Understood this way it should now be clear why the duration of a monitored task is not relevant -- once the "begin task" message has been generated all that has to happen is the sampling agent remembers the span ID. Then when the "end task" message is emitted it has the same span ID. That way the two can be correlated and rendered as a task with some duration. There's always a way to propagate the span ID from place to place (e.g. in a http header so correlation can be done between processes/machines). This explains sibling comments about not being able to track tasks between workflows: the span ID wasn't propagated.