Support trace propagation for gRPC plugin

[lujiajing1126]

Requirement - what kind of business use case are you trying to solve?

Support trace propagation for gRPC plugin

Problem - what in Jaeger blocks you from solving the requirement?

Currently, the trace context is not propagated while using gRPC plugin system. Thus, for example, traces from query API called by UI app and those from actual gRPC plugin are separated. But they are expected to work together to provide more performance insight for the additional storage layer.

So far, there have been already many use-cases for gRPC storage plugin, including Logz.io, InfluxDB and Couchbase as mentioned in the issue #638.

In our production cluster, we are using AlibabaCloud LogService as our storage backend which is heavily inspired by https://github.com/aliyun/aliyun-log-jaeger. And it works as a gRPC plugin in our case.

Proposal - what do you suggest to solve the problem or improve the existing situation?

Inject trace context manually into grpc metadata since DialOption is not supported by go-plugin module now as mentioned in this issue hashicorp/go-plugin#166 and this project seems not in active dev.

It would work similar to upgradeContextWithBearerToken(Context) -> Context.

A PR will be open to resolve this issue.

Any open questions to address

[yurishkuro]

Did you consider proposing a PR to hashicorp/go-plugin? On the surface it sounds like a simple patch, and they have been merging PRs and doing new releases.

[lujiajing1126]

Did you consider proposing a PR to hashicorp/go-plugin? On the surface it sounds like a simple patch, and they have been merging PRs and doing new releases.

Sure, I have made some progress and could have a try first.

[lujiajing1126]

Track PR hashicorp/go-plugin#168

[lujiajing1126]

Track PR hashicorp/go-plugin#168

Since this PR have been merged, I will continue working on this one.