feat(node-sdk): add spanProcessors option

Since span processors can be chained together, it makes sense to expose
this option as an array of span processors. This change also deprecates
the `spanProcessor` option in favor of `spanProcessors`.

experimental/CHANGELOG.md

@@ -10,6 +10,8 @@ All notable changes to experimental packages in this project will be documented
 
 * feat(exporter-metrics-otlp-http): add option to set the exporter aggregation preference  [#4409](https://github.com/open-telemetry/opentelemetry-js/pull/4409) @AkselAllas
 
+* feat(node-sdk): add spanProcessors option [#4454](https://github.com/open-telemetry/opentelemetry-js/pull/4454) @naseemkullah
+
 ### :bug: (Bug Fix)
 
 * fix(sdk-node): allow using samplers when the exporter is defined in the environment [#4394](https://github.com/open-telemetry/opentelemetry-js/pull/4394) @JacksonWeber

experimental/packages/opentelemetry-sdk-node/README.md

@@ -124,6 +124,12 @@ Configure a custom sampler. By default, all traces will be sampled.
 
 ### spanProcessor
 
+Deprecated, please use [spanProcessors](#spanprocessors) instead.
+
+### spanProcessors
+
+An array of span processors to register to the tracer provider.
+
 ### traceExporter
 
 Configure a trace exporter. If an exporter is configured, it will be used with a [BatchSpanProcessor](../../../packages/opentelemetry-sdk-trace-base/src/platform/node/export/BatchSpanProcessor.ts). If an exporter OR span processor is not configured programatically, this package will auto setup the default `otlp` exporter  with `http/protobuf` protocol with a `BatchSpanProcessor`.

experimental/packages/opentelemetry-sdk-node/src/sdk.ts

@@ -75,7 +75,7 @@ export type LoggerProviderConfig = {
 export class NodeSDK {
   private _tracerProviderConfig?: {
     tracerConfig: NodeTracerConfig;
-    spanProcessor: SpanProcessor;
+    spanProcessors: SpanProcessor[];
     contextManager?: ContextManager;
     textMapPropagator?: TextMapPropagator;
   };
@@ -130,7 +130,11 @@ export class NodeSDK {
     this._autoDetectResources = configuration.autoDetectResources ?? true;
 
     // If a tracer provider can be created from manual configuration, create it
-    if (configuration.traceExporter || configuration.spanProcessor) {
+    if (
+      configuration.traceExporter ||
+      configuration.spanProcessor ||
+      configuration.spanProcessors
+    ) {
       const tracerProviderConfig: NodeTracerConfig = {};
 
       if (configuration.sampler) {
@@ -143,13 +147,21 @@ export class NodeSDK {
         tracerProviderConfig.idGenerator = configuration.idGenerator;
       }
 
+      if (configuration.spanProcessor) {
+        diag.warn(
+          "The 'spanProcessor' option is deprecated. Please use 'spanProcessors' instead."
+        );
+      }
+
       const spanProcessor =
         configuration.spanProcessor ??
         new BatchSpanProcessor(configuration.traceExporter!);
 
+      const spanProcessors = configuration.spanProcessors ?? [spanProcessor];
+
       this.configureTracerProvider(
         tracerProviderConfig,
-        spanProcessor,
+        spanProcessors,
         configuration.contextManager,
         configuration.textMapPropagator
       );
@@ -192,13 +204,13 @@ export class NodeSDK {
    */
   public configureTracerProvider(
     tracerConfig: NodeTracerConfig,
-    spanProcessor: SpanProcessor,
+    spanProcessors: SpanProcessor[],
     contextManager?: ContextManager,
     textMapPropagator?: TextMapPropagator
   ): void {
     this._tracerProviderConfig = {
       tracerConfig,
-      spanProcessor,
+      spanProcessors,
       contextManager,
       textMapPropagator,
     };
@@ -334,7 +346,9 @@ export class NodeSDK {
     this._tracerProvider = tracerProvider;
 
     if (this._tracerProviderConfig) {
-      tracerProvider.addSpanProcessor(this._tracerProviderConfig.spanProcessor);
+      for (const spanProcessor of this._tracerProviderConfig.spanProcessors) {
+        tracerProvider.addSpanProcessor(spanProcessor);
+      }
     }
 
     tracerProvider.register({

experimental/packages/opentelemetry-sdk-node/src/types.ts

@@ -40,7 +40,9 @@ export interface NodeSDKConfiguration {
   resourceDetectors: Array<Detector | DetectorSync>;
   sampler: Sampler;
   serviceName?: string;
-  spanProcessor: SpanProcessor;
+  /** @deprecated use spanProcessors instead*/
+  spanProcessor?: SpanProcessor;
+  spanProcessors?: SpanProcessor[];
   traceExporter: SpanExporter;
   spanLimits: SpanLimits;
   idGenerator: IdGenerator;

experimental/packages/opentelemetry-sdk-node/test/sdk.test.ts

@@ -200,12 +200,15 @@ describe('Node SDK', () => {
       delete env.OTEL_TRACES_EXPORTER;
     });
 
-    it('should register a tracer provider if a span processor is provided', async () => {
+    it('should register a tracer provider if a span processors are provided', async () => {
       const exporter = new ConsoleSpanExporter();
-      const spanProcessor = new SimpleSpanProcessor(exporter);
 
       const sdk = new NodeSDK({
-        spanProcessor,
+        spanProcessors: [
+          new NoopSpanProcessor(),
+          new SimpleSpanProcessor(exporter),
+          new BatchSpanProcessor(exporter),
+        ],
         autoDetectResources: false,
       });
 
@@ -223,6 +226,15 @@ describe('Node SDK', () => {
       const apiTracerProvider =
         trace.getTracerProvider() as ProxyTracerProvider;
       assert.ok(apiTracerProvider.getDelegate() instanceof NodeTracerProvider);
+
+      const listOfProcessors =
+        sdk['_tracerProvider']!['_registeredSpanProcessors']!;
+
+      assert(sdk['_tracerProvider'] instanceof NodeTracerProvider);
+      assert(listOfProcessors.length === 3);
+      assert(listOfProcessors[0] instanceof NoopSpanProcessor);
+      assert(listOfProcessors[1] instanceof SimpleSpanProcessor);
+      assert(listOfProcessors[2] instanceof BatchSpanProcessor);
     });
 
     it('should register a meter provider if a reader is provided', async () => {