New sampler: Jaeger remote

[yvrhdn]

Problem Statement

We are migrating from OpenTracing to OpenTelemetry, we use the Jaeger exporter and our apps will their sampling strategies from the OTel Collector.
While jaeger_remote is a known value for OTEL_TRACES_SAMPLER according to the specification, this isn't supported yet by opentelemetry-go.

Is there any work in progress to implement this? Is this something you would accept at this point?

Proposed Solution

Add a new implement of the Sampler interface that uses the Jaeger remote protocol to apply sampling strategies.

Alternatives

I'm not aware of any other remote sampling implementations.

Prior Art

I don't know if any other client library has implemented the Jaeger remote sampler.
The Jaeger receiver in collector has support for remote sampling: https://github.com/open-telemetry/opentelemetry-collector/blob/main/receiver/jaegerreceiver/README.md#remote-sampling

Additional Context

N/A

[Aneurysm9]

I'm not aware of any ongoing work on a remote sampler and I don't think there is any reason why we would not accept one if it were provided.

[yvrhdn]

I've pushed my work in progress here: #2150, if anyone already wants to take a look. I still have a bunch of TODO's to fix and we'll need two new samplers to support all Jaeger strategies (rate limiting and per operation).

[MrAlias]

Related to #327

[MadVikingGod]

The conversation continues in the contrib repo: Add Jaeger remote sampler