Natchez Trace
This is an minimal distributed tracing effect for Cats, inspired by earlier work done on puretracing. It currently has integration with:
It supports
- spans
- numeric, string, and boolean fields
- swizzling to and from http headers
It does not support
- logs
- baggage
If you can make a case for either of these ideas I will consider supporting them, but they seem unnecessary to me.
The Trace effect looks like this:
def doStuff[F[_]: Trace]: F[Whatevs] =
Trace[F].span("span here") {
// Do stuff in F here. This is the extent of the span.
// You can use the instance to:
// - create child spans
// - set data fields
// - extract a set of headers to pass to a remote
// service, which can then continue the trace
}To try it out start up Jaeger as your trace collector.
docker run -d --name jaeger \
-e COLLECTOR_ZIPKIN_HTTP_PORT=9411 \
-p 5775:5775/udp \
-p 6831:6831/udp \
-p 6832:6832/udp \
-p 5778:5778 \
-p 16686:16686 \
-p 14268:14268 \
-p 9411:9411 \
jaegertracing/all-in-one:1.8
Now, finally, if you run the example in modules/examples and go to localhost:16686 you can then select natchez-example and search for traces.
To use it in your own projects (not recommended yet) you can do
// search at sonatype or central for latest version, sorry
libraryDependencies += "org.tpolecat" %% "natchez-jaeger" % <version>