propagator-aws-xray broken with GRPC?

[oceddi]

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What happened?

Steps to Reproduce

Send a gRPC message using AWSXRay propagation from a client to a server. You will see that the 'x-amzn-trace-id' header is not getting parsed correctly by the AXS X-ray propagator during extraction. This results in spans created on the server not getting linked/made children of the originating calling span in the gRPC handlers.

Expected Result

The gRPC handlers on the server side should be linked/parented by the caller.

Actual Result

No linkage is occurring.

Additional Details

I think this bug is caused by the following code in the AWS X-Ray Propagator: https://github.com/open-telemetry/opentelemetry-js/blob/main/packages/propagator-aws-xray/src/AWSXRayPropagator.ts#L102

The code fetches the 'x-amzn-trace-id' from the carrier (the HTTP headers). The gRPC instrumentation provides these as key values where the value is always wrapped in an array (with the first element containing the key). The code in the AWS propagator doesn't account for that and rejects the header if it isn't of type string.

I looked at the other two propagators (B3 and Jaeger) and they seem to properly handle this situation by checking if the value returned from getter.get is an array and pulling element zero from it:

https://github.com/open-telemetry/opentelemetry-js/blob/main/packages/opentelemetry-propagator-b3/src/B3Propagator.ts#L67

https://github.com/open-telemetry/opentelemetry-js/blob/main/packages/opentelemetry-propagator-jaeger/src/JaegerPropagator.ts#L94

Someone needs to update the AWS Xray propagator to do the same check.

OpenTelemetry Setup Code

import process from 'process';
import { Resource } from "@opentelemetry/resources";
import { SEMRESATTRS_SERVICE_NAME } from "@opentelemetry/semantic-conventions";
import { BatchSpanProcessor } from '@opentelemetry/sdk-trace-base';
import { OTLPTraceExporter } from '@opentelemetry/exporter-trace-otlp-grpc';
import { AWSXRayPropagator } from "@opentelemetry/propagator-aws-xray";
import { AWSXRayIdGenerator } from "@opentelemetry/id-generator-aws-xray";
import { GrpcInstrumentation } from '@opentelemetry/instrumentation-grpc';
import { ConsoleMetricExporter, PeriodicExportingMetricReader } from '@opentelemetry/sdk-metrics';
import { getNodeAutoInstrumentations } from '@opentelemetry/auto-instrumentations-node';
import { NodeSDK, api } from '@opentelemetry/sdk-node';
import { AsyncHooksContextManager } from '@opentelemetry/context-async-hooks';

const propagator = new AWSXRayPropagator();
const contextManager = new AsyncHooksContextManager();
contextManager.enable();
api.context.setGlobalContextManager(contextManager);
api.propagation.setGlobalPropagator(propagator);

const resource = Resource.default().merge(new Resource({
  [SEMRESATTRS_SERVICE_NAME]: "myservice",
}));

const traceExporter = new OTLPTraceExporter();
const spanProcessor = new BatchSpanProcessor(traceExporter);

const sdk = new NodeSDK({
  autoDetectResources: true,
  resource,
  idGenerator: new AWSXRayIdGenerator(),
  textMapPropagator: propagator,
  traceExporter,
  spanProcessors: [spanProcessor],
  metricReader: new PeriodicExportingMetricReader({
    exporter: new ConsoleMetricExporter(),
  }),
  instrumentations: [
    new GrpcInstrumentation(),
  ],
});

sdk.start();

const shutdown = () => sdk.shutdown()
  .then(() => console.log('Tracing and Metrics terminated'))
  .catch((error) => console.log('Error terminating tracing and metrics', error))
  .finally(() => process.exit(0));

process.on('SIGTERM', shutdown);
process.on('SIGINT', shutdown);

package.json

"dependencies": {
    "@grpc/grpc-js": "^1.10.9",
    "@grpc/proto-loader": "^0.7.13",
    "@opentelemetry/api": "^1.9.0",
    "@opentelemetry/auto-instrumentations-node": "^0.47.1",
    "@opentelemetry/id-generator-aws-xray": "^1.2.2",
    "@opentelemetry/instrumentation-grpc": "^0.52.1",
    "@opentelemetry/instrumentation-ioredis": "^0.41.0",
    "@opentelemetry/propagator-aws-xray": "^1.25.1",
    "@opentelemetry/resources": "^1.25.1",
    "@opentelemetry/sdk-metrics": "^1.25.1",
    "@opentelemetry/sdk-node": "^0.52.1",
    "@opentelemetry/sdk-trace-node": "^1.25.1",
    "@opentelemetry/semantic-conventions": "^1.25.1",
    "dotenv": "^16.4.5",
    "ioredis": "^5.4.1"
  }

Relevant log output

No response