feat(v2): prompt user when default port is in use

packages/docusaurus/package.json

@@ -54,6 +54,7 @@
     "core-js": "^2.6.5",
     "css-loader": "^3.4.2",
     "del": "^5.1.0",
+    "detect-port": "^1.3.0",
     "eta": "^1.1.1",
     "express": "^4.17.1",
     "fs-extra": "^8.1.0",
@@ -62,6 +63,8 @@
     "html-tags": "^3.1.0",
     "html-webpack-plugin": "^4.0.4",
     "import-fresh": "^3.2.1",
+    "inquirer": "^7.2.0",
+    "is-root": "^2.1.0",
     "lodash.has": "^4.5.2",
     "lodash.isplainobject": "^4.0.6",
     "lodash.isstring": "^4.0.1",
@@ -70,7 +73,6 @@
     "null-loader": "^3.0.0",
     "optimize-css-assets-webpack-plugin": "^5.0.3",
     "pnp-webpack-plugin": "^1.6.4",
-    "portfinder": "^1.0.25",
     "postcss-loader": "^3.0.0",
     "postcss-preset-env": "^6.7.0",
     "react-dev-utils": "^10.2.1",

packages/docusaurus/src/choosePort.ts

@@ -0,0 +1,136 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+/**
+ * This feature was heavily inspired by create-react-app and
+ * uses many of the same utility functions to implement it.
+ */
+
+import {execSync} from 'child_process';
+import detect from 'detect-port';
+import isRoot from 'is-root';
+import chalk from 'chalk';
+import inquirer from 'inquirer';
+
+const isInteractive = process.stdout.isTTY;
+
+const execOptions: object = {
+  encoding: 'utf8',
+  stdio: [
+    'pipe', // stdin (default)
+    'pipe', // stdout (default)
+    'ignore', // stderr
+  ],
+};
+
+// Clears console
+function clearConsole(): void {
+  process.stdout.write(
+    process.platform === 'win32' ? '\x1B[2J\x1B[0f' : '\x1B[2J\x1B[3J\x1B[H',
+  );
+}
+
+// Gets process id of what is on port
+function getProcessIdOnPort(port: number): string {
+  return execSync(`lsof -i:${port} -P -t -sTCP:LISTEN`, execOptions)
+    .toString()
+    .split('\n')[0]
+    .trim();
+}
+
+// Gets process command
+function getProcessCommand(processId: string): Promise<string | null> | string {
+  let command: Buffer | string = execSync(
+    `ps -o command -p ${processId} | sed -n 2p`,
+    execOptions,
+  );
+
+  command = command.toString().replace(/\n$/, '');
+
+  return command;
+}
+
+// Gets directory of a process from its process id
+function getDirectoryOfProcessById(processId: string): string {
+  return execSync(
+    `lsof -p ${processId} | awk '$4=="cwd" {for (i=9; i<=NF; i++) printf "%s ", $i}'`,
+    execOptions,
+  )
+    .toString()
+    .trim();
+}
+
+// Gets process on port
+function getProcessForPort(port: number): string | null {
+  try {
+    const processId = getProcessIdOnPort(port);
+    const directory = getDirectoryOfProcessById(processId);
+    const command = getProcessCommand(processId);
+    return (
+      chalk.cyan(command) +
+      chalk.grey(` (pid ${processId})\n`) +
+      chalk.blue('  in ') +
+      chalk.cyan(directory)
+    );
+  } catch (e) {
+    return null;
+  }
+}
+
+/**
+ * Detects if program is running on port and prompts user
+ * to choose another if port is already being used
+ */
+export default async function choosePort(
+  host: string,
+  defaultPort: number,
+): Promise<number | null> {
+  return detect(defaultPort, host).then(
+    (port) =>
+      new Promise((resolve) => {
+        if (port === defaultPort) {
+          return resolve(port);
+        }
+        const message =
+          process.platform !== 'win32' && defaultPort < 1024 && !isRoot()
+            ? `Admin permissions are required to run a server on a port below 1024.`
+            : `Something is already running on port ${defaultPort}.`;
+        if (isInteractive) {
+          clearConsole();
+          const existingProcess = getProcessForPort(defaultPort);
+          const question: any = {
+            type: 'confirm',
+            name: 'shouldChangePort',
+            message: `${chalk.yellow(
+              `${message}${
+                existingProcess ? ` Probably:\n  ${existingProcess}` : ''
+              }`,
+            )}\n\nWould you like to run the app on another port instead?`,
+            default: true,
+          };
+          inquirer.prompt(question).then((answer: any) => {
+            if (answer.shouldChangePort) {
+              resolve(port);
+            } else {
+              resolve(null);
+            }
+          });
+        } else {
+          console.log(chalk.red(message));
+          resolve(null);
+        }
+        return null;
+      }),
+    (err) => {
+      throw new Error(
+        `${chalk.red(`Could not find an open port at ${chalk.bold(host)}.`)}\n${
+          `Network error message: ${err.message}` || err
+        }\n`,
+      );
+    },
+  );
+}

packages/docusaurus/src/commands/start.ts

@@ -11,7 +11,6 @@ import chokidar from 'chokidar';
 import express from 'express';
 import HtmlWebpackPlugin from 'html-webpack-plugin';
 import path from 'path';
-import portfinder from 'portfinder';
 import openBrowser from 'react-dev-utils/openBrowser';
 import {prepareUrls} from 'react-dev-utils/WebpackDevServerUtils';
 import errorOverlayMiddleware from 'react-dev-utils/errorOverlayMiddleware';
@@ -25,14 +24,18 @@ import {StartCLIOptions} from '@docusaurus/types';
 import {CONFIG_FILE_NAME, STATIC_DIR_NAME, DEFAULT_PORT} from '../constants';
 import createClientConfig from '../webpack/client';
 import {applyConfigureWebpack} from '../webpack/utils';
+import choosePort from '../choosePort';
 
 function getHost(reqHost: string | undefined): string {
   return reqHost || 'localhost';
 }
 
-async function getPort(reqPort: string | undefined): Promise<number> {
+async function getPort(
+  reqPort: string | undefined,
+  host: string,
+): Promise<number | null> {
   const basePort = reqPort ? parseInt(reqPort, 10) : DEFAULT_PORT;
-  const port = await portfinder.getPortPromise({port: basePort});
+  const port = await choosePort(host, basePort);
   return port;
 }
 
@@ -78,8 +81,14 @@ export default async function start(
   );
 
   const protocol: string = process.env.HTTPS === 'true' ? 'https' : 'http';
-  const port: number = await getPort(cliOptions.port);
+
   const host: string = getHost(cliOptions.host);
+  const port: number | null = await getPort(cliOptions.port, host);
+
+  if (port === null) {
+    process.exit();
+  }
+
   const {baseUrl, headTags, preBodyTags, postBodyTags} = props;
   const urls = prepareUrls(protocol, host, port);
   const openUrl = normalizeUrl([urls.localUrlForBrowser, baseUrl]);

yarn.lock

@@ -2839,7 +2839,7 @@
   version "17.1.2"
   resolved "https://registry.yarnpkg.com/@types/hapi__joi/-/hapi__joi-17.1.2.tgz#f547d45b5d33677d1807ec217aeee832dc7e6334"
   integrity sha512-2S6+hBISRQ5Ca6/9zfQi7zPueWMGyZxox6xicqJuW1/aC/6ambLyh+gDqY5fi8JBuHmGKMHldSfEpIXJtTmGKQ==
-  
+
 "@types/history@*":
   version "4.7.6"
   resolved "https://registry.yarnpkg.com/@types/history/-/history-4.7.6.tgz#ed8fc802c45b8e8f54419c2d054e55c9ea344356"
@@ -6615,6 +6615,14 @@ [email protected]:
     address "^1.0.1"
     debug "^2.6.0"
 
+detect-port@^1.3.0:
+  version "1.3.0"
+  resolved "https://registry.yarnpkg.com/detect-port/-/detect-port-1.3.0.tgz#d9c40e9accadd4df5cac6a782aefd014d573d1f1"
+  integrity sha512-E+B1gzkl2gqxt1IhUzwjrxBKRqx1UzC3WLONHinn8S3T6lwV/agVCyitiFOsGJ/eYuEUBvD71MZHy3Pv1G9doQ==
+  dependencies:
+    address "^1.0.1"
+    debug "^2.6.0"
+
 dezalgo@^1.0.0:
   version "1.0.3"
   resolved "https://registry.yarnpkg.com/dezalgo/-/dezalgo-1.0.3.tgz#7f742de066fc748bc8db820569dddce49bf0d456"
@@ -9743,6 +9751,25 @@ inquirer@^7.1.0:
     strip-ansi "^6.0.0"
     through "^2.3.6"
 
+inquirer@^7.2.0:
+  version "7.2.0"
+  resolved "https://registry.yarnpkg.com/inquirer/-/inquirer-7.2.0.tgz#63ce99d823090de7eb420e4bb05e6f3449aa389a"
+  integrity sha512-E0c4rPwr9ByePfNlTIB8z51kK1s2n6jrHuJeEHENl/sbq2G/S1auvibgEwNR4uSyiU+PiYHqSwsgGiXjG8p5ZQ==
+  dependencies:
+    ansi-escapes "^4.2.1"
+    chalk "^3.0.0"
+    cli-cursor "^3.1.0"
+    cli-width "^2.0.0"
+    external-editor "^3.0.3"
+    figures "^3.0.0"
+    lodash "^4.17.15"
+    mute-stream "0.0.8"
+    run-async "^2.4.0"
+    rxjs "^6.5.3"
+    string-width "^4.1.0"
+    strip-ansi "^6.0.0"
+    through "^2.3.6"
+
 internal-ip@^4.3.0:
   version "4.3.0"
   resolved "https://registry.yarnpkg.com/internal-ip/-/internal-ip-4.3.0.tgz#845452baad9d2ca3b69c635a137acb9a0dad0907"
@@ -10206,7 +10233,7 @@ is-retry-allowed@^1.0.0, is-retry-allowed@^1.1.0:
   resolved "https://registry.yarnpkg.com/is-retry-allowed/-/is-retry-allowed-1.2.0.tgz#d778488bd0a4666a3be8a1482b9f2baafedea8b4"
   integrity sha512-RUbUeKwvm3XG2VYamhJL1xFktgjvPzL0Hq8C+6yrWIswDy3BIXGqCxhxkc30N9jqK311gVU137K8Ei55/zVJRg==
 
-[email protected]:
+[email protected], is-root@^2.1.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/is-root/-/is-root-2.1.0.tgz#809e18129cf1129644302a4f8544035d51984a9c"
   integrity sha512-AGOriNp96vNBd3HtU+RzFEc75FfR5ymiYv8E553I71SCeXBiMsVDUtdio1OEFvrPyLIQ9tVR5RxXIFe5PUFjMg==