Allow setting the exported service name using the JAEGER_SERVICE_NAME environment variable

[chgl]

Is your feature request related to a problem? Please describe.

Quite a few options for the Jaeger exporter can already be configured using the JAEGER_ environment variables. However, the service name cannot.

Describe the solution you'd like

Allow setting the exported service name using the JAEGER_SERVICE_NAME environment variable.

Describe alternatives you've considered

Manually set the service name from the env vars:

const options = {
  serviceName: process.env.JAEGER_SERVICE_NAME  || 'my-service',
...
}

Additional context

To implement, a single line may be added to https://github.com/open-telemetry/opentelemetry-js/blob/master/packages/opentelemetry-exporter-jaeger/src/jaeger.ts#L53. I can give it a whirl :)

[vishaltak]

@chgl - Should the environment variables be OTEL_EXPORTER_JAEGER_* as mentioned in the OpenTelemetry specification here ?

Just trying to get information related to #1582

[chgl]

Interesting, thanks for pointing that out! I think ideally both JAEGER_AGENT_HOST and OTEL_EXPORTER_JAEGER_AGENT_HOST should be supported.

In this case though, there's no OTEL equivalent to the JAEGER_SERVICE_NAME, at least not yet: open-telemetry/opentelemetry-specification#709

[vishaltak]

I think ideally both JAEGER_AGENT_HOST and OTEL_EXPORTER_JAEGER_AGENT_HOST should be supported.

What should be the precedence between the two? Jaeger has announced deprecation of it's agent/collector in favour of OpenTelemetry.

In this case though, there's no OTEL equivalent to the JAEGER_SERVICE_NAME, at least not yet: open-telemetry/opentelemetry-specification#709

I could find OTEL_JAEGER_SERVICE_NAME in the Java SDK here. I'm don't think it is consistent across the SDKs.

Also, the parameters used to intialize the Exporter are different across languages. Example: agent host is specified as host in Javscript and as agent_host_name in Python.

[pichlermarc]

Closing as not planned as @opentelemtry/exporter-jaeger is now deprecated and Jaeger now supports OTLP