http: export diagnostics channel for http

doc/api/http.md

@@ -3605,6 +3605,64 @@ try {
 }
 ```
 
+## `http.diagnosticsChannel`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+* `onClientRequestStart`
+* `onClientResponseFinish`
+* `onHTTPRequestStart`
+* `onHTTPResponseFinish`
+
+Examples:
+
+```js
+'use strict';
+
+const http = require('http');
+
+http.diagnosticsChannel.onClientRequestStart.subscribe(({ request }) => {
+});
+
+http.diagnosticsChannel.onClientResponseFinish.subscribe(({ request, response }) => {
+
+});
+
+http.diagnosticsChannel.onHTTPRequestStart.subscribe(({
+  request,
+  response,
+  socket,
+  server,
+}) => {
+
+});
+
+http.diagnosticsChannel.onHTTPResponseFinish.subscribe(({
+  request,
+  response,
+  socket,
+  server,
+}) => {
+
+});
+
+const server = http.createServer((req, res) => {
+  res.end('done');
+});
+
+server.listen(() => {
+  const { port } = server.address();
+  http.get(`http://localhost:${port}`, (res) => {
+    res.resume();
+    res.on('end', () => {
+      server.close();
+    });
+  });
+});
+```
+
 [RFC 8187]: https://www.rfc-editor.org/rfc/rfc8187.txt
 [`'checkContinue'`]: #event-checkcontinue
 [`'finish'`]: #event-finish

lib/_http_client.js

@@ -90,6 +90,10 @@ const {
 
 const kClientRequestStatistics = Symbol('ClientRequestStatistics');
 
+const dc = require('diagnostics_channel');
+const onClientRequestStartChannel = dc.channel('http.client.request.start');
+const onClientResponseFinishChannel = dc.channel('http.client.response.finish');
+
 const { addAbortSignal, finished } = require('stream');
 
 let debug = require('internal/util/debuglog').debuglog('http', (fn) => {
@@ -367,6 +371,11 @@ ClientRequest.prototype._finish = function _finish() {
       },
     });
   }
+  if (onClientRequestStartChannel.hasSubscribers) {
+    onClientRequestStartChannel.publish({
+      request: this,
+    });
+  }
 };
 
 ClientRequest.prototype._implicitHeader = function _implicitHeader() {
@@ -645,6 +654,12 @@ function parserOnIncomingClient(res, shouldKeepAlive) {
       },
     });
   }
+  if (onClientResponseFinishChannel.hasSubscribers) {
+    onClientResponseFinishChannel.publish({
+      request: req,
+      response: res,
+    });
+  }
   req.res = res;
   res.req = req;
 
@@ -927,5 +942,7 @@ ClientRequest.prototype.clearTimeout = function clearTimeout(cb) {
 };
 
 module.exports = {
-  ClientRequest
+  ClientRequest,
+  onClientRequestStartChannel,
+  onClientResponseFinishChannel,
 };

lib/_http_server.js

@@ -1080,5 +1080,7 @@ module.exports = {
   setupConnectionsTracking,
   storeHTTPOptions,
   _connectionListener: connectionListener,
-  kServerResponse
+  kServerResponse,
+  onRequestStartChannel,
+  onResponseFinishChannel,
 };

lib/http.js

@@ -28,7 +28,11 @@ const {
 } = primordials;
 
 const httpAgent = require('_http_agent');
-const { ClientRequest } = require('_http_client');
+const {
+  ClientRequest,
+  onClientRequestStartChannel,
+  onClientResponseFinishChannel,
+} = require('_http_client');
 const { methods } = require('_http_common');
 const { IncomingMessage } = require('_http_incoming');
 const {
@@ -40,7 +44,9 @@ const {
   _connectionListener,
   STATUS_CODES,
   Server,
-  ServerResponse
+  ServerResponse,
+  onRequestStartChannel,
+  onResponseFinishChannel,
 } = require('_http_server');
 let maxHeaderSize;
 
@@ -123,7 +129,13 @@ module.exports = {
   validateHeaderName,
   validateHeaderValue,
   get,
-  request
+  request,
+  diagnosticsChannel: {
+    onClientRequestStart: onClientRequestStartChannel,
+    onClientResponseFinish: onClientResponseFinishChannel,
+    onHTTPRequestStart: onRequestStartChannel,
+    onHTTPResponseFinish: onResponseFinishChannel,
+  },
 };
 
 ObjectDefineProperty(module.exports, 'maxHeaderSize', {

test/parallel/test-diagnostics-channel-http.js

@@ -0,0 +1,51 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const http = require('http');
+
+http.diagnosticsChannel.onClientRequestStart.subscribe(common.mustCall(({ request }) => {
+  assert.strictEqual(typeof request, 'object');
+}));
+
+http.diagnosticsChannel.onClientResponseFinish.subscribe(common.mustCall(({ request, response }) => {
+  assert.strictEqual(typeof request, 'object');
+  assert.strictEqual(typeof response, 'object');
+}));
+
+http.diagnosticsChannel.onHTTPRequestStart.subscribe(common.mustCall(({
+  request,
+  response,
+  socket,
+  server,
+}) => {
+  assert.strictEqual(typeof request, 'object');
+  assert.strictEqual(typeof response, 'object');
+  assert.strictEqual(typeof socket, 'object');
+  assert.strictEqual(typeof server, 'object');
+}));
+
+http.diagnosticsChannel.onHTTPResponseFinish.subscribe(common.mustCall(({
+  request,
+  response,
+  socket,
+  server,
+}) => {
+  assert.strictEqual(typeof request, 'object');
+  assert.strictEqual(typeof response, 'object');
+  assert.strictEqual(typeof socket, 'object');
+  assert.strictEqual(typeof server, 'object');
+}));
+
+const server = http.createServer(common.mustCall((req, res) => {
+  res.end('done');
+}));
+
+server.listen(() => {
+  const { port } = server.address();
+  http.get(`http://localhost:${port}`, (res) => {
+    res.resume();
+    res.on('end', () => {
+      server.close();
+    });
+  });
+});