Drop support for package grpc in instrumentation and examples

[llc1123]

• This only affects the JavaScript OpenTelemetry library

As the package grpc has been deprecated for whole 2 years, everyone should avoid using the package, or at least, in new projects.

Also, the node-gyp part of its installation has never been successful on Windows machines (with the latest node.js runtime), which is annoying for Windows developers like me. I can do the development in WSL2 but it is still a problem if I need to do the web stuff.

So I suggest we drop the support of the package in instrumentation-grpc and remove the grpc example.

[pvogel1967]

This seems particularly appropriate since there's currently a chicken-egg problem in that @opentelemetry/exporter-metrics-grpc itself loads the grpc library which happens before instrumentation is installed, so you always get the warning that you are trying to instrument a library which has already been loaded and so the instrumentation won't work.

[llc1123]

This seems particularly appropriate since there's currently a chicken-egg problem in that @opentelemetry/exporter-metrics-grpc itself loads the grpc library which happens before instrumentation is installed, so you always get the warning that you are trying to instrument a library which has already been loaded and so the instrumentation won't work.

I think the problem will still exist if we keep the package @grpc/grpc-js but I am not sure.

[pichlermarc]

We're actually already using @grpc/grpc-js in the exporters.
Though @opentelemetry/exporter-metrics-otlp-grpc and it's base package is applying some trickery that should prevent that from happening. @pvogel1967 would you mind checking and opening a bug issue if this problem persists in the most recent versions?

[pichlermarc]

I'm not sure what the original reason for combining the instrumentations was, but I'd be all for de-supporting instrumentations for deprecated libraries.

WDYT @open-telemetry/javascript-approvers?

[Flarna]

istrumentation for grpc was created quite some time before instrumentation for grpc-js was added. They share quite some code. An alternative would have been to create a third package grpc instrumentation base but well that ship has sailed.
Meanwhile grpc has been deprecated.

As instrumentation is experimental it's likely ok to remove support for grpc. We removed support for older node.js versions also without moving to 2.0 therefore I think it should be fine to remove grpc in the next minor release.