Add suport to flush via API

The AWS Lambda Plugin as the requirement to flush data at the time the invocation of the function is done. See https://github.com/open-telemetry/opentelemetry-js-contrib/blob/b128dae70cf5723162ef72ed0ed83924f3edf4dc/plugins/node/opentelemetry-instrumentation-aws-lambda/src/aws-lambda.ts#L199-L206

As once can see this creates a binding from instrumentation to a specific SDK. Usually an instrumentation should have no need to require SDK components.

Currently API offers no way to get the TracerProvider used (it returns a ProxyTracerProvider) nor does it offer a way to force flush the trace data.

Should we enhance the API with some functionality regarding this?

[yurishkuro]

I am not clear how this is not addressed by the ForceFlush that is already in the spec? https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/sdk.md#forceflush

[secustor]

Is there any movement on this topic? I have ran into this too as I’m loosing spans if using the batchprocessor.

The stop-gap solution for me has been this snippet, but it is far from ideal:

  const traceProvider = api.trace.getTracerProvider();
  if (traceProvider instanceof NodeTracerProvider) {
    await traceProvider.shutdown();
  } else if (traceProvider instanceof ProxyTracerProvider) {
    const delegateProvider = traceProvider.getDelegate()
    if (delegateProvider instanceof NodeTracerProvider) {
      await delegateProvider.shutdown()
    }
  }