Ask User to use new port if in Use

lib/utils/develop.js

@@ -1,5 +1,6 @@
 /* @flow weak */
 require('node-cjsx').transform()
+import detect from 'detect-port'
 import Hapi from 'hapi'
 import Boom from 'boom'
 import React from 'react'
@@ -13,13 +14,20 @@ import WebpackPlugin from 'hapi-webpack-plugin'
 import opn from 'opn'
 import fs from 'fs'
 import glob from 'glob'
+import rl from 'readline'
+
+const rlInterface = rl.createInterface({
+  input: process.stdin,
+  output: process.stdout,
+})
 
 import globPages from './glob-pages'
 import webpackConfig from './webpack.config'
 const debug = require('debug')('gatsby:application')
 
-module.exports = (program) => {
+function startServer (program, launchPort) {
   const directory = program.directory
+  const serverPort = launchPort || program.port
 
   // Load pages for the site.
   return globPages(directory, (err, pages) => {
@@ -46,11 +54,11 @@ module.exports = (program) => {
       const HTML = factory()
       debug('Configuring develop server')
 
-      // Setup and start Hapi to serve html + static files + webpack-hot-middleware.
       const server = new Hapi.Server()
+
       server.connection({
         host: program.host,
-        port: program.port,
+        port: serverPort,
       })
 
       server.route({
@@ -82,7 +90,7 @@ module.exports = (program) => {
         path: '/{path*}',
         handler: {
           directory: {
-            path: `${directory}/pages`,
+            path: `${program.directory}/pages`,
             listing: false,
             index: false,
           },
@@ -96,7 +104,7 @@ module.exports = (program) => {
         const parsed = parsePath(request.path)
         const page = _.find(pages, (p) => p.path === (`${parsed.dirname}/`))
 
-        let absolutePath = `${directory}/pages`
+        let absolutePath = `${program.directory}/pages`
         let path
         if (page) {
           path = `/${parsePath(page.requirePath).dirname}/${parsed.basename}`
@@ -145,7 +153,7 @@ module.exports = (program) => {
         },
       }
 
-      server.register({
+      return server.register({
         register: WebpackPlugin,
         options: {
           compiler,
@@ -161,20 +169,13 @@ module.exports = (program) => {
         server.start((e) => {
           if (e) {
             if (e.code === 'EADDRINUSE') {
-              const finder = require('process-finder')
-              finder.find({ elevate: false, port: program.port }, (startErr, pids) => {
-                const msg =
-`We were unable to start Gatsby on port ${program.port} as there's already a process
-listening on that port (PID: ${pids[0]}). You can either use a different port
-(e.g. gatsby develop --port ${parseInt(program.port, 10) + 1}) or stop the process already listening
-on your desired port.`
-                console.log(msg)
-                process.exit()
-              })
+              // eslint-disable-next-line max-len
+              console.log(`Unable to start Gatsby on port ${serverPort} as there's already a process listing on that port.`)
             } else {
               console.log(e)
-              process.exit()
             }
+
+            process.exit()
           } else {
             if (program.open) {
               opn(server.info.uri)
@@ -186,3 +187,28 @@ on your desired port.`
     })
   })
 }
+
+module.exports = (program) => {
+  detect(program.port, (err, _port) => {
+    if (err) {
+      console.error(err)
+      process.exit()
+    }
+
+    if (program.port !== _port) {
+      // eslint-disable-next-line max-len
+      const question = `Something is already running at port ${program.port} \nWould you like to run the app at another port instead? [Y/n] `
+
+      return rlInterface.question(question, (answer) => {
+        let launchPort = program.port
+        if (answer.length === 0 || answer.match(/^yes|y$/i)) {
+          launchPort = _port
+        }
+
+        return startServer(program, launchPort)
+      })
+    }
+
+    return startServer(program)
+  })
+}

lib/utils/serve-build.js

@@ -1,21 +1,26 @@
 /* @flow weak */
+import detect from 'detect-port'
 import Hapi from 'hapi'
 import opn from 'opn'
+import rl from 'readline'
+
+const rlInterface = rl.createInterface({
+  input: process.stdin,
+  output: process.stdout,
+})
 
 const debug = require('debug')('gatsby:application')
 
-module.exports = (program) => {
+function startServer (program, launchPort) {
   const directory = program.directory
+  const serverPort = launchPort || program.port
 
   debug('Serving /public')
-
-  // Setup and start Hapi to static files.
-
   const server = new Hapi.Server()
 
   server.connection({
     host: program.host,
-    port: program.port,
+    port: serverPort,
   })
 
   server.route({
@@ -34,19 +39,13 @@ module.exports = (program) => {
   server.start((e) => {
     if (e) {
       if (e.code === 'EADDRINUSE') {
-        const finder = require('process-finder')
-        finder.find({ elevate: false, port: program.port }, (startErr, pids) => {
-          const msg =
-`We were unable to start Gatsby on port ${program.port} as there's already a process
-listening on that port (PID: ${pids[0]}). You can either use a different port
-(e.g. gatsby serve-build --port ${parseInt(program.port, 10) + 1}) or stop the process
-already listening on your desired port.`
-          console.log(msg)
-          process.exit()
-        })
+        // eslint-disable-next-line max-len
+        console.log(`Unable to start Gatsby on port ${serverPort} as there's already a process listing on that port.`)
       } else {
         console.log(e)
       }
+
+      process.exit()
     } else {
       if (program.open) {
         opn(server.info.uri)
@@ -55,3 +54,28 @@ already listening on your desired port.`
     }
   })
 }
+
+module.exports = (program) => {
+  detect(program.port, (err, _port) => {
+    if (err) {
+      console.error(err)
+      process.exit()
+    }
+
+    if (program.port !== _port) {
+      // eslint-disable-next-line max-len
+      const question = `Something is already running at port ${program.port} \nWould you like to run the app at another port instead? [Y/n] `
+
+      return rlInterface.question(question, (answer) => {
+        let launchPort = program.port
+        if (answer.length === 0 || answer.match(/^yes|y$/i)) {
+          launchPort = _port
+        }
+
+        return startServer(program, launchPort)
+      })
+    }
+
+    return startServer(program)
+  })
+}

package.json

@@ -26,6 +26,7 @@
     "commander": "^2.9.0",
     "css-loader": "^0.23.1",
     "debug": "^2.2.0",
+    "detect-port": "^1.0.0",
     "extract-text-webpack-plugin": "^1.0.1",
     "file-loader": "^0.9.0",
     "front-matter": "^2.1.0",
@@ -58,7 +59,6 @@
     "postcss-import": "^8.1.2",
     "postcss-loader": "^0.9.1",
     "postcss-reporter": "^1.4.1",
-    "process-finder": "^1.0.0",
     "raw-loader": "^0.5.1",
     "react": "^15.3.0",
     "react-document-title": "^2.0.1",