http: fix http agent keep alive

Author: theanarkh

lib/_http_agent.js

@@ -342,7 +342,11 @@ Agent.prototype.createSocket = function createSocket(req, options, cb) {
     installListeners(this, s, options);
     cb(null, s);
   });
-
+  // When keepAlive is true, pass the related options to createConnection
+  if (this.keepAlive) {
+    options.keepAlive = this.keepAlive;
+    options.keepAliveInitialDelay = this.keepAliveMsecs;
+  }
   const newSocket = this.createConnection(options, oncreate);
   if (newSocket)
     oncreate(null, newSocket);

test/parallel/test-http-agent-keepalive.js

@@ -81,6 +81,16 @@ function second() {
   }));
 }
 
+function checkSocketKeepAlive(socket) {
+  const symbols = Object.getOwnPropertySymbols(socket);
+  for (const [_, symbol] of Object.entries(symbols)) {
+    if (symbol.toString() === "Symbol(kSetKeepAliveInitialDelay)") {
+      assert.strictEqual(socket[symbol], agent.keepAliveMsecs / 1000);
+      return;
+    }
+  }
+}
+
 function remoteClose() {
   // Mock remote server close the socket
   const req = get('/remote_close', common.mustCall((res) => {
@@ -94,6 +104,7 @@ function remoteClose() {
         assert.strictEqual(agent.sockets[name], undefined);
         assert.strictEqual(agent.freeSockets[name].length, 1);
         assert.strictEqual(agent.totalSocketCount, 1);
+        checkSocketKeepAlive(agent.freeSockets[name][0]);
         // Waiting remote server close the socket
         setTimeout(common.mustCall(() => {
           assert.strictEqual(agent.sockets[name], undefined);