feat: add AWS Lambda detector (#2102)

* feat: add AWS Lambda detector

* chore: document detectors

* chore: issue

Co-authored-by: Valentin Marchaud <[email protected]>

packages/opentelemetry-resource-detector-aws/README.md

@@ -27,7 +27,15 @@ const resource = await detectResources({
 const tracerProvider = new NodeTracerProvider({ resource });
 ```
 
-**Note**: Besides `awsEc2Detector` there are also the following detectors available: `awsBeanstalkDetector`, `awsEksDetector` and `awsEcsDetector`
+## Available detectors
+
+- `awsBeanstalkDetector`: Populates `service` for processes running on [AWS Elastic Beanstalk](https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/Welcome.html)
+- `awsEc2Detector`: Populates `cloud` and `host` for processes running on [Amazon EC2](https://aws.amazon.com/ec2/), including abstractions such as ECS on EC2. Notably, it does not populate anything on AWS Fargate
+- `awsEcsDetector`: Populates `container` for containers running on [Amazon ECS](https://aws.amazon.com/ecs/)
+- `awsEksDetector`: Populates `container` and `k8s.cluster_name` for containers running on [Amazon EKS](https://aws.amazon.com/eks/)
+  - `k8s.cluster_name` is not always available depending on the configuration of CloudWatch monitoring for the EKS cluster
+- `awsLambdaDetector`: Populates `faas` and `cloud` for functions running on [AWS Lambda](https://aws.amazon.com/lambda/)
+  - `faas.id` is currently not populated as it is not provided by the runtime at startup
 
 ## Useful links
 

packages/opentelemetry-resource-detector-aws/src/detectors/AwsLambdaDetector.ts

@@ -0,0 +1,58 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {
+  Detector,
+  Resource,
+  CLOUD_RESOURCE,
+  ResourceDetectionConfig,
+} from '@opentelemetry/resources';
+
+/**
+ * The AwsLambdaDetector can be used to detect if a process is running in AWS Lambda
+ * and return a {@link Resource} populated with data about the environment.
+ * Returns an empty Resource if detection fails.
+ */
+export class AwsLambdaDetector implements Detector {
+  async detect(_config?: ResourceDetectionConfig): Promise<Resource> {
+    const functionName = process.env.AWS_LAMBDA_FUNCTION_NAME;
+    if (!functionName) {
+      return Resource.empty();
+    }
+
+    const functionVersion = process.env.AWS_LAMBDA_FUNCTION_VERSION;
+    const region = process.env.AWS_REGION;
+
+    const attributes = {
+      [CLOUD_RESOURCE.PROVIDER]: 'aws',
+    };
+    if (region) {
+      attributes[CLOUD_RESOURCE.REGION] = region;
+    }
+
+    // TODO(https://github.com/open-telemetry/opentelemetry-js/issues/2123): Migrate to FAAS_RESOURCE when defined.
+    if (functionName) {
+      attributes['faas.name'] = functionName;
+    }
+    if (functionVersion) {
+      attributes['faas.version'] = functionVersion;
+    }
+
+    return new Resource(attributes);
+  }
+}
+
+export const awsLambdaDetector = new AwsLambdaDetector();

packages/opentelemetry-resource-detector-aws/src/detectors/index.ts

@@ -18,3 +18,4 @@ export * from './AwsEc2Detector';
 export * from './AwsBeanstalkDetector';
 export * from './AwsEcsDetector';
 export * from './AwsEksDetector';
+export * from './AwsLambdaDetector';

packages/opentelemetry-resource-detector-aws/test/detectors/AwsLambdaDetector.test.ts

@@ -0,0 +1,64 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import * as assert from 'assert';
+import {
+  assertCloudResource,
+  assertEmptyResource,
+} from '@opentelemetry/resources/test/util/resource-assertions';
+
+import { awsLambdaDetector } from '../../src';
+
+describe('awsLambdaDetector', () => {
+  let oldEnv: NodeJS.ProcessEnv;
+
+  beforeEach(() => {
+    oldEnv = { ...process.env };
+  });
+
+  afterEach(() => {
+    process.env = oldEnv;
+  });
+
+  describe('on lambda', () => {
+    it('fills resource', async () => {
+      process.env.AWS_LAMBDA_FUNCTION_NAME = 'name';
+      process.env.AWS_LAMBDA_FUNCTION_VERSION = 'v1';
+      process.env.AWS_REGION = 'us-east-1';
+
+      const resource = await awsLambdaDetector.detect();
+
+      assertCloudResource(resource, {
+        provider: 'aws',
+        region: 'us-east-1',
+      });
+
+      assert.strictEqual(resource.attributes['faas.name'], 'name');
+      assert.strictEqual(resource.attributes['faas.version'], 'v1');
+    });
+  });
+
+  describe('not on lambda', () => {
+    it('returns empty resource', async () => {
+      process.env.AWS_LAMBDA_FUNCTION_VERSION = 'v1';
+      process.env.AWS_REGION = 'us-east-1';
+
+      const resource = await awsLambdaDetector.detect();
+
+      assertEmptyResource(resource);
+    });
+  });
+});