Natchez log4cats #36
Natchez log4cats #36
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Nice one!
I'm not sure if I'll be able to forgive you that 😉 |
| ( | ||
| headers.get("x-parent-id").map("dd.span_id" -> _) ++ | ||
| headers.get("x-trace-id").map("dd.trace_id" -> _) | ||
| ).toMap |
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I haven't checked the implementation yet, but I remember you were saying something that at the moment you can't add arbitrary tags into the kernel, but there is an open PR in natchez that allows you to do that? Did I get this right?
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Yes it is this: typelevel/natchez#18
For our specific needs I think the trace ID & span ID is enough for now as then Datadog is able to correlate logs to traces, and the traces then have all the other tags
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that makes sense 👍
I'm a little bit surprised because I thought that the "local" propagation was the default behaviour for any tags that you added to your parent span (and they would be propagated all the way down), but perhaps I misunderstood how it worked.
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the natchez-datadog module in this library does indeed do local propagation currently though I am wondering about changing it at some point so it is more consistent with the other Natchez backends - Since all the spans are shown together in a trace I think propagating tags locally probably isn't actually that useful nowadays
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So when the logs are correlated with a span, does it mean that you can then filter/search logs by the tags which are coming from the span? That's effectively the only useful purpose for local propagation from my perspective (so that I can search logs by tags), but if that already happens automatically in datadog, then it's probably not that useful to do the propagation like you're saying
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I don't think you can search logs with APM tags, unless you use natchez-slf4j which relays all the tracing information verbatim to SLF4J (while this module just correlates log4cats log lines with traces)
I think as we use Datadog more hopefully it'll become more obvious what we should do to make things as searchable as possible, I'll probably hold off making any changes until then
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cc @ovotech/engagement-team |
This is a small integration between Natchez & log4cats to allow us to pull headers from the Natchez
kernelinto the log4cats MDC so that in Datadog logs can be correlated with metricsI didn't write any tests since this is so small, please forgive me!