Kotlin extension - coroutines example #188
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| val finishedSpanItems = inMemoryExporter.finishedSpanItems | ||
| println("First child's trace id: ${finishedSpanItems[1].traceId}") // The same as the root span's. | ||
| println("Second child's trace id: ${finishedSpanItems[2].traceId}") // The same as the root span's. |
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You would have a restructure a little bit, but what about moving this to the main method after the latch is awaited? That feels a bit more "finalized" to me and also more clearly shows that this is the demonstrated example output.
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Can you also add the thread.id as an attribute to the spans and print it here? I guess there's no simple way to force the execution to be on a different thread, but it would be a nice visual verification that it works.
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Thanks, I've made some changes to it to clean it up a bit and to move the verification part outside of the coroutine block. I also like the idea of printing the thread.id, so that's added now as well.
| // Bonus: If we wanted to launch a coroutine in a separate thread (not IO, which is the one set in the scope) while | ||
| // keeping the Span context too, we could do so like this: | ||
| // scope.launch(Dispatchers.Main + Context.current().asContextElement()) | ||
| scope.launch(Context.current().asContextElement()) { |
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I'm not a kotlin dev so sorry if I have misunderstood it, but couldn't you just use the Job returned from scope.launch and call join on it to wait for the coroutine to complete? Then you could move everything that comes after createChildrenSpans out of the coroutine. Closing a scope on a thread different from the one that opened it doesn't really work.
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That's a great point, thanks. I wanted to make it easy to read even for non kotlin devs, though it certainly looked a bit strange so I just applied your suggestion and it looks cleaner now.
…wing the same format for other modules
…ify that they were created in different thread and still got the same trace id
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/easycla |
This is an example of how to use the
Context.asContextElementextension function provided in the OTel Java Kotlin extension library in order to preserve a Span context across a coroutine, even if its thread changes.