Forward upgrade from secondary server to primary

lib/server.js

@@ -132,6 +132,7 @@ function multipleBindings (mainServer, httpHandler, serverOpts, listenOptions, o
 
         const secondaryServer = getServerInstance(serverOpts, httpHandler)
         const closeSecondary = () => { secondaryServer.close(() => {}) }
+        secondaryServer.on('upgrade', mainServer.emit.bind(mainServer, 'upgrade'))
         mainServer.on('unref', closeSecondary)
         mainServer.on('close', closeSecondary)
         mainServer.on('error', closeSecondary)

test/upgrade.test.js

@@ -0,0 +1,53 @@
+'use strict'
+
+const { test, skip } = require('tap')
+const { lookup } = require('dns').promises
+const Fastify = require('..')
+const { connect } = require('net')
+const { once } = require('events')
+
+async function setup () {
+  const results = await lookup('localhost', { all: true })
+  if (results.length === 1) {
+    skip('requires both IPv4 and IPv6')
+    return
+  }
+
+  test('upgrade to both servers', async t => {
+    t.plan(2)
+    const app = Fastify()
+    app.server.on('upgrade', (req, socket, head) => {
+      t.pass(`upgrade event ${JSON.stringify(socket.address())}`)
+      socket.end()
+    })
+    app.get('/', (req, res) => {
+    })
+    await app.listen()
+    t.teardown(app.close.bind(app))
+
+    {
+      const client = connect(app.server.address().port, '127.0.0.1')
+      client.write('GET / HTTP/1.1\r\n')
+      client.write('Upgrade: websocket\r\n')
+      client.write('Connection: Upgrade\r\n')
+      client.write('Sec-WebSocket-Key: x3JJHMbDL1EzLkh9GBhXDw==\r\n')
+      client.write('Sec-WebSocket-Protocol: com.xxx.service.v1\r\n')
+      client.write('Sec-WebSocket-Version: 13\r\n\r\n')
+      client.write('\r\n\r\n')
+      await once(client, 'close')
+    }
+
+    {
+      const client = connect(app.server.address().port, '::1')
+      client.write('GET / HTTP/1.1\r\n')
+      client.write('Upgrade: websocket\r\n')
+      client.write('Connection: Upgrade\r\n')
+      client.write('Sec-WebSocket-Key: x3JJHMbDL1EzLkh9GBhXDw==\r\n')
+      client.write('Sec-WebSocket-Protocol: com.xxx.service.v1\r\n')
+      client.write('Sec-WebSocket-Version: 13\r\n\r\n')
+      await once(client, 'close')
+    }
+  })
+}
+
+setup()