Extract API Key from Secrets Manager when using the metrics API client (#609)

get API key secret from secrets manager

Author: DylanLovesCoffee

src/index.ts

@@ -31,6 +31,7 @@ import { SpanOptions, TracerWrapper } from "./trace/tracer-wrapper";
 export { DatadogTraceHeaders as TraceHeaders } from "./trace/context/extractor";
 export const apiKeyEnvVar = "DD_API_KEY";
 export const apiKeyKMSEnvVar = "DD_KMS_API_KEY";
+export const apiKeySecretARNEnvVar = "DD_API_KEY_SECRET_ARN";
 export const captureLambdaPayloadEnvVar = "DD_CAPTURE_LAMBDA_PAYLOAD";
 export const captureLambdaPayloadMaxDepthEnvVar = "DD_CAPTURE_LAMBDA_PAYLOAD_MAX_DEPTH";
 export const traceManagedServicesEnvVar = "DD_TRACE_MANAGED_SERVICES";
@@ -76,6 +77,7 @@ export type Config = MetricsConfig & TraceConfig & GlobalConfig;
 export const defaultConfig: Config = {
   apiKey: "",
   apiKeyKMS: "",
+  apiKeySecretARN: "",
   autoPatchHTTP: true,
   captureLambdaPayload: false,
   captureLambdaPayloadMaxDepth: 10,
@@ -344,6 +346,10 @@ function getConfig(userConfig?: Partial<Config>): Config {
     config.apiKeyKMS = getEnvValue(apiKeyKMSEnvVar, "");
   }
 
+  if (config.apiKeySecretARN === "") {
+    config.apiKeySecretARN = getEnvValue(apiKeySecretARNEnvVar, "");
+  }
+
   if (userConfig === undefined || userConfig.injectLogContext === undefined) {
     const result = getEnvValue(logInjectionEnvVar, "true").toLowerCase();
     config.injectLogContext = result === "true";

src/metrics/listener.spec.ts

@@ -9,6 +9,16 @@ import StatsDClient from "hot-shots";
 import { Context } from "aws-lambda";
 jest.mock("hot-shots");
 
+jest.mock("aws-sdk/clients/secretsmanager", () => {
+  return jest.fn().mockImplementation(() => ({
+    getSecretValue: jest.fn().mockReturnValue({
+      promise: jest.fn().mockResolvedValue({
+        SecretString: "api-key-secret",
+      }),
+    }),
+  }));
+});
+
 const siteURL = "example.com";
 
 class MockKMS {
@@ -34,6 +44,7 @@ describe("MetricsListener", () => {
     const listener = new MetricsListener(kms as any, {
       apiKey: "api-key",
       apiKeyKMS: "kms-api-key-encrypted",
+      apiKeySecretARN: "api-key-secret-arn",
       enhancedMetrics: false,
       logForwarding: false,
       shouldRetryMetrics: false,
@@ -54,6 +65,7 @@ describe("MetricsListener", () => {
     const listener = new MetricsListener(kms as any, {
       apiKey: "",
       apiKeyKMS: "kms-api-key-encrypted",
+      apiKeySecretARN: "api-key-secret-arn",
       enhancedMetrics: false,
       logForwarding: false,
       shouldRetryMetrics: false,
@@ -67,11 +79,35 @@ describe("MetricsListener", () => {
 
     expect(nock.isDone()).toBeTruthy();
   });
+
+  it("extracts the API Key from the secret manager to send a metric", async () => {
+    nock("https://api.example.com").post("/api/v1/distribution_points?api_key=api-key-secret").reply(200, {});
+
+    const kms = new MockKMS("kms-api-key-decrypted");
+    const listener = new MetricsListener(kms as any, {
+      apiKey: "",
+      apiKeyKMS: "",
+      apiKeySecretARN: "api-key-secret-arn",
+      enhancedMetrics: false,
+      logForwarding: false,
+      shouldRetryMetrics: false,
+      localTesting: false,
+      siteURL,
+    });
+
+    await listener.onStartInvocation({});
+    listener.sendDistributionMetricWithDate("my-metric", 10, new Date(), false, "tag:a", "tag:b");
+    await listener.onCompleteInvocation();
+
+    expect(nock.isDone()).toBeTruthy();
+  });
+
   it("doesn't throw an error if it can't get a valid apiKey", async () => {
     const kms = new MockKMS("kms-api-key-decrypted", new Error("The error"));
     const listener = new MetricsListener(kms as any, {
       apiKey: "",
       apiKeyKMS: "kms-api-key-encrypted",
+      apiKeySecretARN: "api-key-secret-arn",
       enhancedMetrics: false,
       logForwarding: false,
       shouldRetryMetrics: false,
@@ -91,6 +127,7 @@ describe("MetricsListener", () => {
     const listener = new MetricsListener(kms as any, {
       apiKey: "api-key",
       apiKeyKMS: "kms-api-key-encrypted",
+      apiKeySecretARN: "api-key-secret-arn",
       enhancedMetrics: false,
       logForwarding: true,
       shouldRetryMetrics: false,
@@ -124,6 +161,7 @@ describe("MetricsListener", () => {
     const listener = new MetricsListener(kms as any, {
       apiKey: "api-key",
       apiKeyKMS: "",
+      apiKeySecretARN: "api-key-secret-arn",
       enhancedMetrics: false,
       logForwarding: true,
       shouldRetryMetrics: false,
@@ -159,6 +197,7 @@ describe("MetricsListener", () => {
     const listener = new MetricsListener(kms as any, {
       apiKey: "api-key",
       apiKeyKMS: "",
+      apiKeySecretARN: "api-key-secret-arn",
       enhancedMetrics: false,
       logForwarding: false,
       shouldRetryMetrics: false,
@@ -198,6 +237,7 @@ describe("MetricsListener", () => {
     const listener = new MetricsListener(kms as any, {
       apiKey: "api-key",
       apiKeyKMS: "",
+      apiKeySecretARN: "api-key-secret-arn",
       enhancedMetrics: false,
       logForwarding: false,
       shouldRetryMetrics: false,
@@ -219,6 +259,7 @@ describe("MetricsListener", () => {
     const listener = new MetricsListener(kms as any, {
       apiKey: "api-key",
       apiKeyKMS: "kms-api-key-encrypted",
+      apiKeySecretARN: "api-key-secret-arn",
       enhancedMetrics: false,
       logForwarding: true,
       shouldRetryMetrics: false,

src/metrics/listener.ts

@@ -28,6 +28,10 @@ export interface MetricsConfig {
    * be decrypted before any metrics are sent.
    */
   apiKeyKMS: string;
+  /**
+   * An api key stored in secrets manager used to talk to the Datadog API.
+   */
+  apiKeySecretARN: string;
   /**
    * The site of the Datadog URL to send to. This should either be 'datadoghq.com', (default),
    * or 'datadoghq.eu', for customers in the eu.
@@ -215,6 +219,17 @@ export class MetricsListener {
         logError("couldn't decrypt kms api key", error as Error);
       }
     }
+
+    if (config.apiKeySecretARN !== "") {
+      try {
+        const { default: secretsClient } = await import("aws-sdk/clients/secretsmanager");
+        const secretsManager = new secretsClient();
+        const secret = await secretsManager.getSecretValue({ SecretId: config.apiKeySecretARN }).promise();
+        return secret?.SecretString ?? "";
+      } catch (error) {
+        logError("couldn't get secrets manager api key", error as Error);
+      }
+    }
     return "";
   }