hotrod docker image and configurable jaeger agent host and port

[jkandasa]

• Currently, there is no docker image to run HotROD example. It will be nice to have separate Docker image for HotROD
• HotROD works with the agent running on 127.0.0.1, Will be nice to have configurable agent port and IP.

[pavelnikolov]

This would be really nice. In the mean time, you can use this image https://hub.docker.com/r/mikelorant/jaeger-hotrod/ it accepts AGENT_HOST and AGENT_PORT environment variables.

[yurishkuro]

@pavelnikolov would you like to submit a PR to add a hotrod image to the travis step that builds the other images?

[pavelnikolov]

I was about to submit a PR for that, but then I noticed the hotrod code needed some changes as @jkandasa has pointed out above. I didn't have time to do it and @mikelorant created the image I liked above (repo here). Although it works, it's a little hacky workaround and needs to be done properly.
I'll try to submit a PR soon and fix the hotrod code. Then creating a proper image would be a trivial task.

[yurishkuro]

I assume you mean this issue in the client: jaegertracing/jaeger-client-go#197

[pavelnikolov]

No, it's different issue. I think that the hotrod app (from memory) is hardcoded to send tracing only to localhost. This is the reason Mike has forwarded traffic from port 6831/udp to external host and port in his Docker image, suing socat:

socat UDP4-RECVFROM:6831,fork UDP4-SENDTO:${AGENT_HOST}:${AGENT_PORT} &

The fix is to allow hotrod to be configurable and to send data to custom host and port.

[pavolloffay]

@pavelnikolov #663 added a flag to configure agent address

[pavelnikolov]

This will save me some time. I'll try to create Docker file using it and will send a PR.

[pavolloffay]

Partially implemented in #694