[SVLS-4422] Support metrics with timestamps when the Extension is running (#522)

SVLS-4422: support metrics with timestamps when the extension is running

Author: DylanLovesCoffee

src/metrics/listener.spec.ts

@@ -138,6 +138,51 @@ describe("MetricsListener", () => {
     expect(distributionMock).toHaveBeenCalledWith("my-metric", 10, undefined, ["tag:a", "tag:b"]);
   });
 
+  it("only sends metrics with timestamps to the API when the extension is enabled", async () => {
+    const flushScope = nock(EXTENSION_URL).post("/lambda/flush", JSON.stringify({})).reply(200);
+    mock({
+      "/opt/extensions/datadog-agent": Buffer.from([0]),
+    });
+    nock("https://api.example.com").post("/api/v1/distribution_points?api_key=api-key").reply(200, {});
+
+    const distributionMock = jest.fn();
+    (StatsDClient as any).mockImplementation(() => {
+      return {
+        distribution: distributionMock,
+        close: (callback: any) => callback(undefined),
+      };
+    });
+
+    jest.spyOn(Date, "now").mockImplementation(() => 1487076708000);
+
+    const metricTimeOneMinuteAgo = new Date(Date.now() - 60000);
+    const kms = new MockKMS("kms-api-key-decrypted");
+    const listener = new MetricsListener(kms as any, {
+      apiKey: "api-key",
+      apiKeyKMS: "",
+      enhancedMetrics: false,
+      logForwarding: false,
+      shouldRetryMetrics: false,
+      localTesting: true,
+      siteURL,
+    });
+
+    await listener.onStartInvocation({});
+    listener.sendDistributionMetricWithDate(
+      "my-metric-with-a-timestamp",
+      10,
+      metricTimeOneMinuteAgo,
+      false,
+      "tag:a",
+      "tag:b",
+    );
+    listener.sendDistributionMetric("my-metric-without-a-timestamp", 10, false, "tag:a", "tag:b");
+    await listener.onCompleteInvocation();
+    expect(flushScope.isDone()).toBeTruthy();
+    expect(nock.isDone()).toBeTruthy();
+    expect(distributionMock).toHaveBeenCalledWith("my-metric-without-a-timestamp", 10, undefined, ["tag:a", "tag:b"]);
+  });
+
   it("logs metrics when logForwarding is enabled with custom timestamp", async () => {
     const spy = jest.spyOn(process.stdout, "write");
     // jest.spyOn(Date, "now").mockImplementation(() => 1487076708000);

src/metrics/listener.ts

@@ -131,13 +131,20 @@ export class MetricsListener {
   public sendDistributionMetricWithDate(
     name: string,
     value: number,
-    metricTime: Date,
+    metricTime: Date, // TODO: Next breaking change to update to optional or 'Date | undefined'?
     forceAsync: boolean,
     ...tags: string[]
   ) {
     if (this.isExtensionRunning) {
-      this.statsDClient?.distribution(name, value, undefined, tags);
-      return;
+      const isMetricTimeValid = Date.parse(metricTime.toString()) > 0;
+      if (isMetricTimeValid) {
+        // Only create the processor to submit metrics to the API when a user provides a valid timestamp as
+        // Dogstatsd does not support timestamps for distributions.
+        this.currentProcessor = this.createProcessor(this.config, this.apiKey);
+      } else {
+        this.statsDClient?.distribution(name, value, undefined, tags);
+        return;
+      }
     }
     if (this.config.logForwarding || forceAsync) {
       writeMetricToStdout(name, value, metricTime, tags);
@@ -162,11 +169,13 @@ export class MetricsListener {
   }
 
   public sendDistributionMetric(name: string, value: number, forceAsync: boolean, ...tags: string[]) {
-    this.sendDistributionMetricWithDate(name, value, new Date(Date.now()), forceAsync, ...tags);
+    // The Extension doesn't support distribution metrics with timestamps. Use sendDistributionMetricWithDate instead.
+    const metricTime = this.isExtensionRunning ? new Date(0) : new Date(Date.now());
+    this.sendDistributionMetricWithDate(name, value, metricTime, forceAsync, ...tags);
   }
 
   private async createProcessor(config: MetricsConfig, apiKey: Promise<string>) {
-    if (!this.isExtensionRunning && !this.config.logForwarding) {
+    if (!this.config.logForwarding) {
       const { APIClient } = require("./api");
       const { Processor } = require("./processor");