http: add diagnostic channel http.client.request.created

PR-URL: #55586Fixes: #55352
Reviewed-By: Paolo Insogna <paolo@cowtech.it>
Reviewed-By: Jake Yuesong Li <jake.yuesong@gmail.com>
Reviewed-By: theanarkh <theratliter@gmail.com>

Author: marco-ippolito

doc/api/diagnostics_channel.md

@@ -1123,6 +1123,13 @@ independently.
 
 #### HTTP
 
+`http.client.request.created`
+
+*`request` {http.ClientRequest}
+
+Emitted when client creates a request object.
+Unlike `http.client.request.start`, this event is emitted before the request has been sent.
+
 `http.client.request.start`
 
 *`request` {http.ClientRequest}

lib/_http_client.js

@@ -89,6 +89,7 @@ const {
 constkClientRequestStatistics=Symbol('ClientRequestStatistics');
 
 constdc=require('diagnostics_channel');
+constonClientRequestCreatedChannel=dc.channel('http.client.request.created');
 constonClientRequestStartChannel=dc.channel('http.client.request.start');
 constonClientRequestErrorChannel=dc.channel('http.client.request.error');
 constonClientResponseFinishChannel=dc.channel('http.client.response.finish');
@@ -373,6 +374,11 @@ function ClientRequest(input, options, cb) {
 this.onSocket(net.createConnection(opts));
 }
 }
+if(onClientRequestCreatedChannel.hasSubscribers){
+onClientRequestCreatedChannel.publish({
+request: this,
+});
+}
 }
 ObjectSetPrototypeOf(ClientRequest.prototype,OutgoingMessage.prototype);
 ObjectSetPrototypeOf(ClientRequest,OutgoingMessage);

test/parallel/test-diagnostic-channel-http-request-created.js

@@ -0,0 +1,39 @@
+'use strict';
+constcommon=require('../common');
+constassert=require('assert');
+consthttp=require('http');
+constdc=require('diagnostics_channel');
+
+constisHTTPServer=(server)=>serverinstanceofhttp.Server;
+constisOutgoingMessage=(object)=>objectinstanceofhttp.OutgoingMessage;
+
+dc.subscribe('http.client.request.created',common.mustCall(({ request })=>{
+assert.strictEqual(request.getHeader('foo'),'bar');
+assert.strictEqual(request.getHeader('baz'),undefined);
+assert.strictEqual(isOutgoingMessage(request),true);
+assert.strictEqual(isHTTPServer(server),true);
+}));
+
+dc.subscribe('http.client.request.start',common.mustCall(({ request })=>{
+assert.strictEqual(request.getHeader('foo'),'bar');
+assert.strictEqual(request.getHeader('baz'),'bar');
+assert.strictEqual(isOutgoingMessage(request),true);
+}));
+
+constserver=http.createServer(common.mustCall((_,res)=>{
+res.end('done');
+}));
+
+server.listen(async()=>{
+const{ port }=server.address();
+constreq=http.request({
+ port,
+headers: {
+'foo': 'bar',
+}
+},common.mustCall(()=>{
+server.close();
+}));
+req.setHeader('baz','bar');
+req.end();
+});

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

@@ -53,6 +53,11 @@ dc.subscribe('http.server.response.finish', common.mustCall(({
 assert.strictEqual(isHTTPServer(server),true);
 }));
 
+dc.subscribe('http.client.request.created',common.mustCall(({ request })=>{
+assert.strictEqual(isOutgoingMessage(request),true);
+assert.strictEqual(isHTTPServer(server),true);
+},2));
+
 constserver=http.createServer(common.mustCall((req,res)=>{
 res.end('done');
 }));