Pure Tracing

A POC to provide an opentracing equivalent standard for pure applications. This repo contains the proposed interfaces, cats implementation, and few example applications.

Run the examples

sbt examplePrintlnTracing/run

This runs application with dummy println-based backed, just to see how the context get's propagated.

If you want see a more involved example, run the open tracing example, but first we need Jaeger instance running

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

then

sbt exampleOpenTracing/run

once the program finished, navigate to localhost:16686, then from the first drop down menu select "pure-application", then click find traces.

Todo

• [x] Add inject & extract methods to Tracer
• [x] Integrate with http-client library to propagation outgoing http calls
• [ ] Integrate with http4s to propagate from incoming http calls
• [ ] AWS XRay implementation

Proposal highlights

• api module with zero dependecies, contains Tracer interface and Propagation type-class
• cats module provides ergonomic dsl, and Propagation implementation using Reader monad.
• cats-opentracing module provides Tracer implementation for any opentracing.Tracer
• Propagation is essentially ApplicativeLocal, but hides the Environment type param for ergonomics.
• Tracer#Span get's set by each implementation, allows integration with non-opentracing like AWS XRay.