Remove old SigV4 headers before signing (#159)

*Description of changes:*
There was a bug where the old headers were not cleaned before the
request was signed causing 403 errors to occur when exporting traces to
XRay OTLP endpoint.

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Author: liustve

aws-distro-opentelemetry-node-autoinstrumentation/src/aws-opentelemetry-configurator.ts

@@ -448,6 +448,7 @@ export class AwsSpanProcessorProvider {
         return new OTLPHttpTraceExporter();
       case 'http/protobuf':
         if (otlp_exporter_traces_endpoint && isXrayOtlpEndpoint(otlp_exporter_traces_endpoint)) {
+          diag.debug('Detected XRay OTLP Traces endpoint. Switching exporter to OtlpAwsSpanExporter');
           return new OTLPAwsSpanExporter(otlp_exporter_traces_endpoint);
         }
         return new OTLPProtoTraceExporter();
@@ -457,6 +458,7 @@ export class AwsSpanProcessorProvider {
       default:
         diag.warn(`Unsupported OTLP traces protocol: ${protocol}. Using http/protobuf.`);
         if (otlp_exporter_traces_endpoint && isXrayOtlpEndpoint(otlp_exporter_traces_endpoint)) {
+          diag.debug('Detected XRay OTLP Traces endpoint. Switching exporter to OtlpAwsSpanExporter');
           return new OTLPAwsSpanExporter(otlp_exporter_traces_endpoint);
         }
         return new OTLPProtoTraceExporter();

aws-distro-opentelemetry-node-autoinstrumentation/src/otlp-aws-span-exporter.ts

@@ -66,7 +66,7 @@ export class OTLPAwsSpanExporter extends OTLPProtoTraceExporter {
           path: url.pathname,
           body: serializedSpans,
           headers: {
-            ...oldHeaders,
+            ...this.removeSigV4Headers(oldHeaders),
             host: url.hostname,
           },
         });
@@ -93,6 +93,19 @@ export class OTLPAwsSpanExporter extends OTLPProtoTraceExporter {
     await super.export(items, resultCallback);
   }
 
+  // Removes Sigv4 headers from old headers to avoid accidentally copying them to the new headers
+  private removeSigV4Headers(headers: Record<string, string>) {
+    const newHeaders: Record<string, string> = {};
+    const sigV4Headers = ['x-amz-date', 'authorization', 'x-amz-content-sha256', 'x-amz-security-token'];
+
+    for (const key in headers) {
+      if (!sigV4Headers.includes(key.toLowerCase())) {
+        newHeaders[key] = headers[key];
+      }
+    }
+    return newHeaders;
+  }
+
   private initDependencies(): any {
     if (getNodeVersion() < 16) {
       diag.error('SigV4 signing requires atleast Node major version 16');