Create sync resource with some attributes that resolve asynchronously

CHANGELOG.md

@@ -12,6 +12,7 @@ For experimental package changes, see the [experimental CHANGELOG](experimental/
 ### :rocket: (Enhancement)
 
 * feat(api): add `getActiveBaggage` API [#3385](https://github.com/open-telemetry/opentelemetry-js/pull/3385)
+* feat(resource): create sync resource with some attributes that resolve asynchronously [#3460](https://github.com/open-telemetry/opentelemetry-js/pull/3460)
 
 ### :bug: (Bug Fix)
 

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

@@ -21,7 +21,7 @@ import {
 } from '@opentelemetry/instrumentation';
 import {
   Detector,
-  detectResources,
+  detectResourcesSync,
   envDetector,
   processDetector,
   Resource,
@@ -174,12 +174,12 @@ export class NodeSDK {
   }
 
   /** Detect resource attributes */
-  public async detectResources(): Promise<void> {
+  public detectResources(): void {
     const internalConfig: ResourceDetectionConfig = {
       detectors: this._resourceDetectors,
     };
 
-    this.addResource(await detectResources(internalConfig));
+    this.addResource(detectResourcesSync(internalConfig));
   }
 
   /** Manually add a resource */
@@ -190,9 +190,9 @@ export class NodeSDK {
   /**
    * Once the SDK has been configured, call this method to construct SDK components and register them with the OpenTelemetry API.
    */
-  public async start(): Promise<void> {
+  public start(): void {
     if (this._autoDetectResources) {
-      await this.detectResources();
+      this.detectResources();
     }
 
     this._resource =

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

@@ -87,7 +87,7 @@ describe('Node SDK', () => {
         autoDetectResources: false,
       });
 
-      await sdk.start();
+      sdk.start();
 
       assert.strictEqual(
         context['_getContextManager'](),
@@ -114,7 +114,7 @@ describe('Node SDK', () => {
         autoDetectResources: false,
       });
 
-      await sdk.start();
+      sdk.start();
 
       assert.ok(!(metrics.getMeterProvider() instanceof MeterProvider));
 
@@ -139,7 +139,7 @@ describe('Node SDK', () => {
         autoDetectResources: false,
       });
 
-      await sdk.start();
+      sdk.start();
 
       assert.ok(!(metrics.getMeterProvider() instanceof MeterProvider));
 
@@ -171,7 +171,7 @@ describe('Node SDK', () => {
         autoDetectResources: false,
       });
 
-      await sdk.start();
+      sdk.start();
 
       assert.strictEqual(
         context['_getContextManager'](),
@@ -237,7 +237,7 @@ describe('Node SDK', () => {
       autoDetectResources: false,
     });
 
-    await sdk.start();
+    sdk.start();
 
     assert.strictEqual(
       context['_getContextManager'](),
@@ -420,8 +420,9 @@ describe('Node SDK', () => {
           ],
         });
 
-        await sdk.detectResources();
+        sdk.detectResources();
         const resource = sdk['_resource'];
+        await resource.waitForAsyncAttributes();
 
         assertServiceResource(resource, {
           instanceId: '627cc493',
@@ -468,7 +469,8 @@ describe('Node SDK', () => {
           DiagLogLevel.VERBOSE
         );
 
-        await sdk.detectResources();
+        sdk.detectResources();
+        await sdk['_resource'].waitForAsyncAttributes().catch(() => {});
 
         // Test that the Env Detector successfully found its resource and populated it with the right values.
         assert.ok(
@@ -500,7 +502,7 @@ describe('Node SDK', () => {
             DiagLogLevel.DEBUG
           );
 
-          await sdk.detectResources();
+          sdk.detectResources();
 
           assert.ok(
             callArgsContains(
@@ -519,7 +521,7 @@ describe('Node SDK', () => {
         serviceName: 'config-set-name',
       });
 
-      await sdk.start();
+      sdk.start();
       const resource = sdk['_resource'];
 
       assertServiceResource(resource, {
@@ -531,7 +533,7 @@ describe('Node SDK', () => {
       process.env.OTEL_SERVICE_NAME = 'env-set-name';
       const sdk = new NodeSDK();
 
-      await sdk.start();
+      sdk.start();
       const resource = sdk['_resource'];
 
       assertServiceResource(resource, {
@@ -546,7 +548,7 @@ describe('Node SDK', () => {
         serviceName: 'config-set-name',
       });
 
-      await sdk.start();
+      sdk.start();
       const resource = sdk['_resource'];
 
       assertServiceResource(resource, {
@@ -560,7 +562,7 @@ describe('Node SDK', () => {
         'service.name=resource-env-set-name';
       const sdk = new NodeSDK();
 
-      await sdk.start();
+      sdk.start();
       const resource = sdk['_resource'];
 
       assertServiceResource(resource, {
@@ -576,7 +578,7 @@ describe('Node SDK', () => {
         serviceName: 'config-set-name',
       });
 
-      await sdk.start();
+      sdk.start();
       const resource = sdk['_resource'];
 
       assertServiceResource(resource, {
@@ -604,7 +606,7 @@ describe('setup exporter from env', () => {
   });
   it('use default exporter TracerProviderWithEnvExporters when user does not provide span processor or trace exporter to sdk config', async () => {
     const sdk = new NodeSDK();
-    await sdk.start();
+    sdk.start();
     const listOfProcessors =
       sdk['_tracerProvider']!['_registeredSpanProcessors']!;
 
@@ -617,7 +619,7 @@ describe('setup exporter from env', () => {
     const sdk = new NodeSDK({
       traceExporter,
     });
-    await sdk.start();
+    sdk.start();
     const listOfProcessors =
       sdk['_tracerProvider']!['_registeredSpanProcessors']!;
 
@@ -634,7 +636,7 @@ describe('setup exporter from env', () => {
     const sdk = new NodeSDK({
       spanProcessor,
     });
-    await sdk.start();
+    sdk.start();
     const listOfProcessors =
       sdk['_tracerProvider']!['_registeredSpanProcessors']!;
 
@@ -651,7 +653,7 @@ describe('setup exporter from env', () => {
     const sdk = new NodeSDK({
       traceExporter,
     });
-    await sdk.start();
+    sdk.start();
     const listOfProcessors =
       sdk['_tracerProvider']!['_registeredSpanProcessors']!;
 
@@ -667,7 +669,7 @@ describe('setup exporter from env', () => {
     env.OTEL_TRACES_EXPORTER = 'otlp';
     env.OTEL_EXPORTER_OTLP_TRACES_PROTOCOL = 'grpc';
     const sdk = new NodeSDK();
-    await sdk.start();
+    sdk.start();
 
     const listOfProcessors =
       sdk['_tracerProvider']!['_registeredSpanProcessors']!;
@@ -680,7 +682,7 @@ describe('setup exporter from env', () => {
   it('use noop span processor when user sets env exporter to none', async () => {
     env.OTEL_TRACES_EXPORTER = 'none';
     const sdk = new NodeSDK();
-    await sdk.start();
+    sdk.start();
 
     const listOfProcessors =
       sdk['_tracerProvider']!['_registeredSpanProcessors']!;
@@ -693,7 +695,7 @@ describe('setup exporter from env', () => {
   it('log warning that sdk will not be initalized when exporter is set to none', async () => {
     env.OTEL_TRACES_EXPORTER = 'none';
     const sdk = new NodeSDK();
-    await sdk.start();
+    sdk.start();
 
     assert.strictEqual(
       stubLoggerError.args[0][0],
@@ -704,7 +706,7 @@ describe('setup exporter from env', () => {
   it('do not use any exporters when empty value is provided for exporter', async () => {
     env.OTEL_TRACES_EXPORTER = '';
     const sdk = new NodeSDK();
-    await sdk.start();
+    sdk.start();
 
     const listOfProcessors =
       sdk['_tracerProvider']!['_registeredSpanProcessors']!;
@@ -718,7 +720,7 @@ describe('setup exporter from env', () => {
   it('use only default exporter when none value is provided with other exporters', async () => {
     env.OTEL_TRACES_EXPORTER = 'otlp,zipkin,none';
     const sdk = new NodeSDK();
-    await sdk.start();
+    sdk.start();
 
     const listOfProcessors =
       sdk['_tracerProvider']!['_registeredSpanProcessors']!;
@@ -731,7 +733,7 @@ describe('setup exporter from env', () => {
   it('log warning that only default exporter will be used since exporter list contains none with other exports ', async () => {
     env.OTEL_TRACES_EXPORTER = 'otlp,zipkin,none';
     const sdk = new NodeSDK();
-    await sdk.start();
+    sdk.start();
 
     assert.strictEqual(
       stubLoggerError.args[0][0],
@@ -742,7 +744,7 @@ describe('setup exporter from env', () => {
   it('should warn that provided exporter value is unrecognized and not able to be set up', async () => {
     env.OTEL_TRACES_EXPORTER = 'invalid';
     const sdk = new NodeSDK();
-    await sdk.start();
+    sdk.start();
 
     assert.strictEqual(
       stubLoggerError.args[0][0],
@@ -760,7 +762,7 @@ describe('setup exporter from env', () => {
     env.OTEL_TRACES_EXPORTER = 'zipkin, otlp, jaeger';
     env.OTEL_EXPORTER_OTLP_TRACES_PROTOCOL = 'grpc';
     const sdk = new NodeSDK();
-    await sdk.start();
+    sdk.start();
 
     const listOfProcessors =
       sdk['_tracerProvider']!['_registeredSpanProcessors']!;
@@ -776,7 +778,7 @@ describe('setup exporter from env', () => {
   it('use the console exporter', async () => {
     env.OTEL_TRACES_EXPORTER = 'console, otlp';
     const sdk = new NodeSDK();
-    await sdk.start();
+    sdk.start();
 
     const listOfProcessors =
       sdk['_tracerProvider']!['_registeredSpanProcessors']!;

packages/opentelemetry-resources/src/Resource.ts

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+import { diag } from '@opentelemetry/api';
 import { SemanticResourceAttributes } from '@opentelemetry/semantic-conventions';
 import { SDK_INFO } from '@opentelemetry/core';
 import { ResourceAttributes } from './types';
@@ -25,6 +26,9 @@ import { defaultServiceName } from './platform';
  */
 export class Resource {
   static readonly EMPTY = new Resource({});
+  private _attributes: ResourceAttributes;
+  private _asyncAttributesPromise: Promise<ResourceAttributes> | undefined;
+  private _asyncAttributesHaveResolved: boolean;
 
   /**
    * Returns an empty Resource
@@ -34,7 +38,7 @@ export class Resource {
   }
 
   /**
-   * Returns a Resource that indentifies the SDK in use.
+   * Returns a Resource that identifies the SDK in use.
    */
   static default(): Resource {
     return new Resource({
@@ -54,8 +58,50 @@ export class Resource {
      * information about the entity as numbers, strings or booleans
      * TODO: Consider to add check/validation on attributes.
      */
-    readonly attributes: ResourceAttributes
-  ) {}
+    attributes: ResourceAttributes,
+    asyncAttributesPromise?: Promise<ResourceAttributes>
+  ) {
+    this._attributes = attributes;
+    this._asyncAttributesHaveResolved = asyncAttributesPromise === undefined;
+    this._asyncAttributesPromise = asyncAttributesPromise?.then(
+      asyncAttributes => {
+        this._attributes = Object.assign({}, this._attributes, asyncAttributes);
+        this._asyncAttributesHaveResolved = true;
+        return asyncAttributes;
+      }
+    );
+    this._asyncAttributesPromise?.catch(err => {
+      diag.debug("The resource's async promise rejected: %s", err);
+      this._asyncAttributesHaveResolved = true;
+      return {};
+    });
+  }
+
+  get attributes(): ResourceAttributes {
+    return this._attributes;
+  }
+
+  /**
+   * Check if async attributes have resolved. This is useful to avoid awaiting
+   * waitForAsyncAttributes (which will introduce asynchronous behavior) when not necessary.
+   *
+   * @returns true if no async attributes promise was provided or if the promise has resolved
+   * and been merged together with the sync attributes.
+   */
+  asyncAttributesHaveResolved(): boolean {
+    return this._asyncAttributesHaveResolved;
+  }
+
+  /**
+   * Returns a promise that resolves when all async attributes have finished being added to
+   * this Resource's attributes. This is useful in exporters to block until resource detection
+   * has finished.
+   */
+  async waitForAsyncAttributes(): Promise<void> {
+    if (!this._asyncAttributesHaveResolved) {
+      await this._asyncAttributesPromise;
+    }
+  }
 
   /**
    * Returns a new, merged {@link Resource} by merging the current Resource
@@ -66,14 +112,28 @@ export class Resource {
    * @returns the newly merged Resource.
    */
   merge(other: Resource | null): Resource {
-    if (!other || !Object.keys(other.attributes).length) return this;
+    if (!other) return this;
 
     // SpanAttributes from resource overwrite attributes from other resource.
     const mergedAttributes = Object.assign(
       {},
       this.attributes,
       other.attributes
     );
-    return new Resource(mergedAttributes);
+
+    let mergedAsyncAttributesPromise: Promise<ResourceAttributes> | undefined;
+    if (this._asyncAttributesPromise && other._asyncAttributesPromise) {
+      mergedAsyncAttributesPromise = Promise.all([
+        this._asyncAttributesPromise.catch(() => ({})),
+        other._asyncAttributesPromise.catch(() => ({})),
+      ]).then(([thisAttributes, otherAttributes]) => {
+        return Object.assign({}, thisAttributes, otherAttributes);
+      });
+    } else {
+      mergedAsyncAttributesPromise =
+        this._asyncAttributesPromise ?? other._asyncAttributesPromise;
+    }
+
+    return new Resource(mergedAttributes, mergedAsyncAttributesPromise);
   }
 }