From 7bdb2745392810ca2b5cfe2007c8ddfd013f6f44 Mon Sep 17 00:00:00 2001
From: Anuraag Agrawal <aanuraag@amazon.co.jp>
Date: Mon, 12 Apr 2021 15:40:31 +0900
Subject: [PATCH] feat: add AWS Lambda detector

---
 .../src/detectors/AwsLambdaDetector.ts        | 58 +++++++++++++++++
 .../src/detectors/index.ts                    |  1 +
 .../test/detectors/AwsLambdaDetector.test.ts  | 64 +++++++++++++++++++
 3 files changed, 123 insertions(+)
 create mode 100644 packages/opentelemetry-resource-detector-aws/src/detectors/AwsLambdaDetector.ts
 create mode 100644 packages/opentelemetry-resource-detector-aws/test/detectors/AwsLambdaDetector.test.ts

diff --git a/packages/opentelemetry-resource-detector-aws/src/detectors/AwsLambdaDetector.ts b/packages/opentelemetry-resource-detector-aws/src/detectors/AwsLambdaDetector.ts
new file mode 100644
index 0000000000..0f42442398
--- /dev/null
+++ b/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(anuraaga): 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();
diff --git a/packages/opentelemetry-resource-detector-aws/src/detectors/index.ts b/packages/opentelemetry-resource-detector-aws/src/detectors/index.ts
index e873f14e89..b475e4a208 100644
--- a/packages/opentelemetry-resource-detector-aws/src/detectors/index.ts
+++ b/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';
diff --git a/packages/opentelemetry-resource-detector-aws/test/detectors/AwsLambdaDetector.test.ts b/packages/opentelemetry-resource-detector-aws/test/detectors/AwsLambdaDetector.test.ts
new file mode 100644
index 0000000000..0487a0b708
--- /dev/null
+++ b/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);
+    });
+  });
+});