NodeSDK configuration with sampler and other settings not applied when using exporter from env

[anuraaga]

What happened?

Steps to Reproduce

Configure NodeSDK with sampler: new AlwaysOffSampler() but no traceExporter and run with OTEL_TRACES_EXPORTER=console.

Expected Result

No spans are logged

Actual Result

All spans are logged because the sampler setting is ignored

Additional Details

It seems to be related to only reading the configuration when exporter is defined

https://github.com/open-telemetry/opentelemetry-js/blob/main/experimental/packages/opentelemetry-sdk-node/src/sdk.ts#L132

But I guess intuitively, the configuration is supposed to work even when using environment variable selection for exporter.

Note, while the example above for simplicitly is using alwaysoffsampler, and thus could have been configured with env var, actually I want to use a custom sampler so need to set it programatically.

OpenTelemetry Setup Code

export const otelSdk = new NodeSDK({
  instrumentations: [
    new DnsInstrumentation(),
    new GrpcInstrumentation(),
    new HttpInstrumentation(),
    new NestInstrumentation(),
    new NetInstrumentation(),
    new PrismaInstrumentation(),
    new WinstonInstrumentation(),
  ],
  sampler: new AlwaysOffSampler(),
});

package.json

Leaving this out since the code in `main` seems obvious enough

Relevant log output

No response

[pichlermarc]

this seems to be already fixed by #4394
See reproducer repo: https://github.com/pichlermarc/repro-4004/tree/main