[Bug] `@temporalio/interceptors-opentelemetry` OTEL bypasses a required SDK component

[sdedovic]

What are you really trying to do?

When using the @temporalio/interceptors-opentelemetry library I am seeing TONS of these errors:

ERROR --- node_modules/@opentelemetry/api/build/src/api/diag.js : ["Accessing resource attributes before async attributes settled"]

which are caused by the Temporal SDKs improper use of the OTEL SDK.

Describe the bug

See this comment on the issue in the OTEL SDK: open-telemetry/opentelemetry-js#5828 (comment). To quote the linked comment, from one of the OTEL maintainers

Looking at the code it looks like the following is happening:\

• @temporalio/interceptors-opentelemetry bypasses the SpanProcessor which is supposed to await the async attributes and passes spans directly to SpanExporter
• the SpanExporter then assumes that the resource was already awaited by the SpanProcessor, but since @temporalio/interceptors-opentelemetry bypassed the SpanProcessor this never happened.
• during normal operation of an OTel SDK, this log is not written - this happens since @temporalio/interceptors-opentelemetry bypasses a required SDK component.

Recommendation: @temporalio/interceptors-opentelemetry should accept a SpanProcessor instead of a SpanExporter in makeWorkflowExporter(), and pass the spans to SpanProcessor#onEnd(Span) instead. This will properly await the resource attributes before exporting them, log errors and and handle batching in a user-configurable way, which may be desirable.

Minimal Reproduction

See last comment on this issue: open-telemetry/opentelemetry-js#5828 (comment)

export function makeWorkflowExporter(
  spanProcessor: SpanProcessor, // used with a BatchSpanProcessor for instance, which forwards to a SpanExporter
  resource: Resource
): InjectedSink<OpenTelemetryWorkflowExporter> {
  // note: somehow, `SpanProcessor#shutdown()` needs to be wired up somewhere to avoid data loss on shutdown.
  return {
    export: {
      fn: (info, spanData) => {
        const spans = spanData.forEach((serialized) => {
          Object.assign(serialized.attributes, info);
          // Spans are copied over from the isolate and are converted to ReadableSpan instances
          spanProcessor.onEnd(extractReadableSpan(serialized, resource));
        });
      },
    },
  };
}

Environment/Versions

• OS and processor: x86_64-linux
• Temporal Version: [e.g. 1.14.0?] and/or SDK version
• Temporal from source

Additional context

This will affect #1741