#491: adding compression to metrics API

src/index.spec.ts

@@ -10,6 +10,7 @@ import { PassThrough } from "stream";
 import { DatadogTraceHeaders } from "./trace/context/extractor";
 import { SpanContextWrapper } from "./trace/span-context-wrapper";
 import { TraceSource } from "./trace/trace-context-service";
+import { inflateSync } from "zlib";
 
 jest.mock("./metrics/enhanced-metrics");
 
@@ -141,7 +142,11 @@ describe("datadog", () => {
     process.env[apiKeyVar] = apiKey;
 
     nock("https://api.datadoghq.com")
-      .post(`/api/v1/distribution_points?api_key=${apiKey}`, (request: any) => request.series[0].metric === "my-dist")
+      .post(
+        `/api/v1/distribution_points?api_key=${apiKey}`,
+        (request: any) =>
+          JSON.parse(inflateSync(Buffer.from(request, "hex")).toString()).series[0].metric === "my-dist",
+      )
       .reply(200, {});
 
     const wrapped = datadog(
@@ -163,7 +168,11 @@ describe("datadog", () => {
     const apiKey = "101112";
 
     nock("https://api.datadoghq.com")
-      .post(`/api/v1/distribution_points?api_key=${apiKey}`, (request: any) => request.series[0].metric === "my-dist")
+      .post(
+        `/api/v1/distribution_points?api_key=${apiKey}`,
+        (request: any) =>
+          JSON.parse(inflateSync(Buffer.from(request, "hex")).toString()).series[0].metric === "my-dist",
+      )
       .reply(200, {});
 
     const wrapped = datadog(
@@ -185,7 +194,11 @@ describe("datadog", () => {
     process.env[siteEnvVar] = site;
 
     nock("https://api.datadoghq.com")
-      .post(`/api/v1/distribution_points?api_key=${apiKey}`, (request: any) => request.series[0].metric === "my-dist")
+      .post(
+        `/api/v1/distribution_points?api_key=${apiKey}`,
+        (request: any) =>
+          JSON.parse(inflateSync(Buffer.from(request, "hex")).toString()).series[0].metric === "my-dist",
+      )
       .reply(200, {});
 
     const wrapped = datadog(
@@ -207,7 +220,11 @@ describe("datadog", () => {
     process.env[siteEnvVar] = site;
 
     nock("https://api.datadoghq.com")
-      .post(`/api/v1/distribution_points?api_key=${apiKey}`, (request: any) => request.series[0].metric === "my-dist")
+      .post(
+        `/api/v1/distribution_points?api_key=${apiKey}`,
+        (request: any) =>
+          JSON.parse(inflateSync(Buffer.from(request, "hex")).toString()).series[0].metric === "my-dist",
+      )
       .reply(200, {});
 
     const wrapped = datadog(

src/metrics/api.spec.ts

@@ -2,6 +2,7 @@ import nock from "nock";
 
 import { APIClient } from "./api";
 import { APIMetric } from "./model";
+import { deflateSync } from "zlib";
 
 const baseAPIURL = "https://www.example.com";
 
@@ -31,7 +32,9 @@ describe("APIClient", () => {
     ];
 
     const scope = nock(baseAPIURL)
-      .post("/api/v1/distribution_points?api_key=api_key", JSON.stringify({ series: input }))
+      .post("/api/v1/distribution_points?api_key=api_key", deflateSync(JSON.stringify({ series: input })), {
+        reqheaders: { "content-encoding": "deflate" },
+      })
       .reply(200);
     const client = new APIClient("api_key", baseAPIURL);
 
@@ -41,7 +44,9 @@ describe("APIClient", () => {
 
   it("throws an authentication error on authentication failure", async () => {
     const scope = nock(baseAPIURL)
-      .post("/api/v1/distribution_points?api_key=bad_api_key", JSON.stringify({ series: [] }))
+      .post("/api/v1/distribution_points?api_key=bad_api_key", deflateSync(JSON.stringify({ series: [] })), {
+        reqheaders: { "content-encoding": "deflate" },
+      })
       .reply(403);
     const client = new APIClient("bad_api_key", baseAPIURL);
     await expect(client.sendMetrics([])).rejects.toMatchInlineSnapshot(`"HTTP error code: 403"`);
@@ -50,7 +55,9 @@ describe("APIClient", () => {
 
   it("throws an error on connection error failure", async () => {
     const scope = nock(baseAPIURL)
-      .post("/api/v1/distribution_points?api_key=api_key", JSON.stringify({ series: [] }))
+      .post("/api/v1/distribution_points?api_key=api_key", deflateSync(JSON.stringify({ series: [] })), {
+        reqheaders: { "content-encoding": "deflate" },
+      })
       .replyWithError("Connection closed");
     const client = new APIClient("api_key", baseAPIURL);
     await expect(client.sendMetrics([])).rejects.toMatchInlineSnapshot(`"Connection closed"`);

src/metrics/api.ts

@@ -18,7 +18,7 @@ export class APIClient implements Client {
   constructor(private apiKey: string, private baseAPIURL: string) {}
 
   public async sendMetrics(metrics: APIMetric[]): Promise<void> {
-    const result = await post(this.getUrl("api/v1/distribution_points"), { series: metrics });
+    const result = await post(this.getUrl("api/v1/distribution_points"), { series: metrics }, {}, true);
     if (result.success) {
       return;
     }

src/metrics/listener.spec.ts

@@ -1,4 +1,3 @@
-import { AWSError, KMS, Request } from "aws-sdk";
 import nock from "nock";
 import mock from "mock-fs";
 

src/utils/request.ts

@@ -2,16 +2,31 @@ import https, { RequestOptions } from "https";
 import http from "http";
 import { URL } from "url";
 import { logDebug } from "./log";
+import { deflateSync } from "zlib";
 
 type RequestResult = {
   success: boolean;
   statusCode?: number;
   errorMessage?: string;
 };
 
-export function post<T>(url: URL, body: T, options?: Partial<RequestOptions>): Promise<RequestResult> {
+export function post<T>(
+  url: URL,
+  body: T,
+  options?: Partial<RequestOptions>,
+  compressPayload?: boolean,
+): Promise<RequestResult> {
   const bodyJSON = JSON.stringify(body);
-  const buffer = Buffer.from(bodyJSON);
+  let buffer = Buffer.from(bodyJSON);
+
+  if (compressPayload) {
+    // Adding compression header
+    options = options || {}; // Define options object if not already defined
+    options.headers = { ...options.headers, "Content-Encoding": "deflate" };
+
+    buffer = deflateSync(buffer);
+  }
+
   logDebug(`sending payload with body ${bodyJSON}`);
   const requestOptions: RequestOptions = {
     headers: { "content-type": "application/json" },