cli: remove --select-chrome,--skip-autolaunch. Support CHROME_PATH env (#2659)

* --skip-autolaunch flag removed, --select-chrome flag removed
* Unused chrome-launcher/ask.ts removed
* Added support for CHROME_PATH env variable to replace LIGHTHOUSE_CHROMIUM_PATH
* CHROME_PATH env variable documented in CLI help
* Added support for CHROME_PATH on macOS

Author: arturmiz

chrome-launcher/ask.ts

@@ -9,6 +9,7 @@ const fs = require('fs');
 const path = require('path');
 const execSync = require('child_process').execSync;
 const execFileSync = require('child_process').execFileSync;
+const log = require('lighthouse-logger');
 
 const newLineRegex = /\r?\n/;
 
@@ -23,6 +24,11 @@ export function darwin() {
 
   const installations: Array<string> = [];
 
+  const customChromePath = resolveChromePath();
+  if (customChromePath) {
+    installations.push(customChromePath);
+  }
+
   execSync(
       `${LSREGISTER} -dump` +
       ' | grep -i \'google chrome\\( canary\\)\\?.app$\'' +
@@ -46,25 +52,43 @@ export function darwin() {
     {regex: /^\/Applications\/.*Chrome.app/, weight: 100},
     {regex: /^\/Applications\/.*Chrome Canary.app/, weight: 101},
     {regex: /^\/Volumes\/.*Chrome.app/, weight: -2},
-    {regex: /^\/Volumes\/.*Chrome Canary.app/, weight: -1}
+    {regex: /^\/Volumes\/.*Chrome Canary.app/, weight: -1},
+    {regex: new RegExp(process.env.LIGHTHOUSE_CHROMIUM_PATH), weight: 150},
+    {regex: new RegExp(process.env.CHROME_PATH), weight: 151}
   ];
   // clang-format on
 
   return sort(installations, priorities);
 }
 
+function resolveChromePath() {
+  if (canAccess(process.env.CHROME_PATH)) {
+    return process.env.CHROME_PATH as string;
+  }
+
+  if (canAccess(process.env.LIGHTHOUSE_CHROMIUM_PATH)) {
+    log.warn(
+        'ChromeLauncher',
+        'LIGHTHOUSE_CHROMIUM_PATH is deprecated, use CHROME_PATH env variable instead.');
+    return process.env.LIGHTHOUSE_CHROMIUM_PATH as string;
+  }
+
+  return undefined;
+}
+
 /**
  * Look for linux executables in 3 ways
- * 1. Look into LIGHTHOUSE_CHROMIUM_PATH env variable
+ * 1. Look into CHROME_PATH env variable
  * 2. Look into the directories where .desktop are saved on gnome based distro's
  * 3. Look for google-chrome-stable & google-chrome executables by using the which command
  */
 export function linux() {
   let installations: string[] = [];
 
-  // 1. Look into LIGHTHOUSE_CHROMIUM_PATH env variable
-  if (canAccess(process.env.LIGHTHOUSE_CHROMIUM_PATH)) {
-    installations.push(process.env.LIGHTHOUSE_CHROMIUM_PATH as string);
+  // 1. Look into CHROME_PATH env variable
+  const customChromePath = resolveChromePath();
+  if (customChromePath) {
+    installations.push(customChromePath);
   }
 
   // 2. Look into the directories where .desktop are saved on gnome based distro's
@@ -96,14 +120,15 @@ export function linux() {
 
   if (!installations.length) {
     throw new Error(
-        'The environment variable LIGHTHOUSE_CHROMIUM_PATH must be set to ' +
+        'The environment variable CHROME_PATH must be set to ' +
         'executable of a build of Chromium version 54.0 or later.');
   }
 
   const priorities: Priorities = [
     {regex: /chrome-wrapper$/, weight: 51}, {regex: /google-chrome-stable$/, weight: 50},
     {regex: /google-chrome$/, weight: 49},
-    {regex: new RegExp(process.env.LIGHTHOUSE_CHROMIUM_PATH), weight: 100}
+    {regex: new RegExp(process.env.LIGHTHOUSE_CHROMIUM_PATH), weight: 100},
+    {regex: new RegExp(process.env.CHROME_PATH), weight: 101}
   ];
 
   return sort(uniq(installations.filter(Boolean)), priorities);
@@ -117,8 +142,9 @@ export function win32() {
   const prefixes =
       [process.env.LOCALAPPDATA, process.env.PROGRAMFILES, process.env['PROGRAMFILES(X86)']];
 
-  if (canAccess(process.env.LIGHTHOUSE_CHROMIUM_PATH)) {
-    installations.push(process.env.LIGHTHOUSE_CHROMIUM_PATH);
+  const customChromePath = resolveChromePath();
+  if (customChromePath) {
+    installations.push(customChromePath);
   }
 
   prefixes.forEach(prefix => suffixes.forEach(suffix => {

chrome-launcher/chrome-finder.ts

@@ -12,9 +12,9 @@ const Driver = require('../lighthouse-core/gather/driver.js');
 import {GetValidOutputOptions, OutputMode} from './printer';
 
 export interface Flags {
-  skipAutolaunch: boolean, port: number, selectChrome: boolean, chromeFlags: string, output: any,
-      outputPath: string, interactive: boolean, saveArtifacts: boolean, saveAssets: boolean,
-      view: boolean, maxWaitForLoad: number, logLevel: string
+  port: number, chromeFlags: string, output: any, outputPath: string, interactive: boolean,
+      saveArtifacts: boolean, saveAssets: boolean, view: boolean, maxWaitForLoad: number,
+      logLevel: string
 }
 
 export function getFlags(manualArgv?: string) {
@@ -71,14 +71,15 @@ export function getFlags(manualArgv?: string) {
             'Additional categories to capture with the trace (comma-delimited).',
         'config-path': 'The path to the config JSON.',
         'chrome-flags':
-            'Custom flags to pass to Chrome (space-delimited). For a full list of flags, see http://peter.sh/experiments/chromium-command-line-switches/.',
+            `Custom flags to pass to Chrome (space-delimited). For a full list of flags, see http://peter.sh/experiments/chromium-command-line-switches/.
+
+            Environment variables:
+            CHROME_PATH: Explicit path of intended Chrome binary. If set must point to an executable of a build of Chromium version 54.0 or later. By default, any detected Chrome Canary or Chrome (stable) will be launched.
+            `,
         'perf': 'Use a performance-test-only configuration',
         'port': 'The port to use for the debugging protocol. Use 0 for a random port',
         'max-wait-for-load':
             'The timeout (in milliseconds) to wait before the page is considered done loading and the run should continue. WARNING: Very high values can lead to large traces and instability',
-        'skip-autolaunch': 'Skip autolaunch of Chrome when already running instance is not found',
-        'select-chrome':
-            'Interactively choose version of Chrome to use when multiple installations are found',
         'interactive': 'Open Lighthouse in interactive mode'
       })
 
@@ -97,8 +98,7 @@ Example: --output-path=./lighthouse-results.html`,
       .boolean([
         'disable-storage-reset', 'disable-device-emulation', 'disable-cpu-throttling',
         'disable-network-throttling', 'save-assets', 'save-artifacts', 'list-all-audits',
-        'list-trace-categories', 'perf', 'view', 'skip-autolaunch', 'select-chrome', 'verbose',
-        'quiet', 'help', 'interactive'
+        'list-trace-categories', 'perf', 'view', 'verbose', 'quiet', 'help', 'interactive'
       ])
       .choices('output', GetValidOutputOptions())
 

lighthouse-cli/cli-flags.ts

@@ -29,8 +29,7 @@ interface LighthouseError extends Error {
 
 /**
  * Attempts to connect to an instance of Chrome with an open remote-debugging
- * port. If none is found and the `skipAutolaunch` flag is not true, launches
- * a debuggable instance.
+ * port. If none is found, launches a debuggable instance.
  */
 async function getDebuggableChrome(flags: Flags) {
   return await launch(
@@ -39,9 +38,6 @@ async function getDebuggableChrome(flags: Flags) {
 
 function showConnectionError() {
   console.error('Unable to connect to Chrome');
-  console.error(
-      'If you\'re using lighthouse with --skip-autolaunch, ' +
-      'make sure you\'re running some other Chrome with a debugger.');
   process.exit(_RUNTIME_ERROR_CODE);
 }
 

lighthouse-cli/run.ts

@@ -77,8 +77,6 @@ Options:
   --disable-device-emulation    Disable Nexus 5X emulation                                                                                 [boolean]
   --disable-cpu-throttling      Disable CPU throttling                                                                    [boolean] [default: false]
   --disable-network-throttling  Disable network throttling                                                                                 [boolean]
-  --skip-autolaunch             Skip autolaunch of Chrome when already running instance is not found                                       [boolean]
-  --select-chrome               Interactively choose version of Chrome to use when multiple installations are found                        [boolean]
   --interactive                 Open Lighthouse in interactive mode                                                                        [boolean]
 
 Examples: