core(lantern): add configuration for precomputed network analysis

lighthouse-cli/bin.js

@@ -24,15 +24,15 @@ const path = require('path');
 const commands = require('./commands/commands.js');
 const printer = require('./printer.js');
 const getFlags = require('./cli-flags.js').getFlags;
-const runLighthouse = require('./run').runLighthouse;
+const runLighthouse = require('./run.js').runLighthouse;
 const generateConfig = require('../lighthouse-core/index.js').generateConfig;
 
 const log = require('lighthouse-logger');
 const pkg = require('../package.json');
-const Sentry = require('../lighthouse-core/lib/sentry');
+const Sentry = require('../lighthouse-core/lib/sentry.js');
 
 const updateNotifier = require('update-notifier');
-const askPermission = require('./sentry-prompt').askPermission;
+const askPermission = require('./sentry-prompt.js').askPermission;
 
 /**
  * @return {boolean}
@@ -41,74 +41,85 @@ function isDev() {
   return fs.existsSync(path.join(__dirname, '../.git'));
 }
 
-// Tell user if there's a newer version of LH.
-updateNotifier({pkg}).notify();
-
-const cliFlags = getFlags();
+/**
+ * @return {Promise<LH.RunnerResult|void>}
+ */
+async function begin() {
+  // Tell user if there's a newer version of LH.
+  updateNotifier({pkg}).notify();
 
-// Process terminating command
-if (cliFlags.listAllAudits) {
-  commands.listAudits();
-}
+  const cliFlags = getFlags();
 
-// Process terminating command
-if (cliFlags.listTraceCategories) {
-  commands.listTraceCategories();
-}
+  // Process terminating command
+  if (cliFlags.listAllAudits) {
+    commands.listAudits();
+  }
 
-const url = cliFlags._[0];
-
-/** @type {LH.Config.Json|undefined} */
-let configJson;
-if (cliFlags.configPath) {
-  // Resolve the config file path relative to where cli was called.
-  cliFlags.configPath = path.resolve(process.cwd(), cliFlags.configPath);
-  configJson = /** @type {LH.Config.Json} */ (require(cliFlags.configPath));
-} else if (cliFlags.preset) {
-  if (cliFlags.preset === 'mixed-content') {
-    // The mixed-content audits require headless Chrome (https://crbug.com/764505).
-    cliFlags.chromeFlags = `${cliFlags.chromeFlags} --headless`;
+  // Process terminating command
+  if (cliFlags.listTraceCategories) {
+    commands.listTraceCategories();
   }
 
-  configJson = require(`../lighthouse-core/config/${cliFlags.preset}-config.js`);
-}
+  const url = cliFlags._[0];
+
+  /** @type {LH.Config.Json|undefined} */
+  let configJson;
+  if (cliFlags.configPath) {
+    // Resolve the config file path relative to where cli was called.
+    cliFlags.configPath = path.resolve(process.cwd(), cliFlags.configPath);
+    configJson = /** @type {LH.Config.Json} */ (require(cliFlags.configPath));
+  } else if (cliFlags.preset) {
+    if (cliFlags.preset === 'mixed-content') {
+      // The mixed-content audits require headless Chrome (https://crbug.com/764505).
+      cliFlags.chromeFlags = `${cliFlags.chromeFlags} --headless`;
+    }
+
+    configJson = require(`../lighthouse-core/config/${cliFlags.preset}-config.js`);
+  }
 
-// set logging preferences
-cliFlags.logLevel = 'info';
-if (cliFlags.verbose) {
-  cliFlags.logLevel = 'verbose';
-} else if (cliFlags.quiet) {
-  cliFlags.logLevel = 'silent';
-}
-log.setLevel(cliFlags.logLevel);
-
-if (
-  cliFlags.output.length === 1 &&
-  cliFlags.output[0] === printer.OutputMode.json &&
-  !cliFlags.outputPath
-) {
-  cliFlags.outputPath = 'stdout';
-}
+  // set logging preferences
+  cliFlags.logLevel = 'info';
+  if (cliFlags.verbose) {
+    cliFlags.logLevel = 'verbose';
+  } else if (cliFlags.quiet) {
+    cliFlags.logLevel = 'silent';
+  }
+  log.setLevel(cliFlags.logLevel);
+
+  if (
+    cliFlags.output.length === 1 &&
+    cliFlags.output[0] === printer.OutputMode.json &&
+    !cliFlags.outputPath
+  ) {
+    cliFlags.outputPath = 'stdout';
+  }
 
-if (cliFlags.extraHeaders) {
-  // TODO: LH.Flags.extraHeaders is actually a string at this point, but needs to be
-  // copied over to LH.Settings.extraHeaders, which is LH.Crdp.Network.Headers. Force
-  // the conversion here, but long term either the CLI flag or the setting should have
-  // a different name.
-  // @ts-ignore
-  let extraHeadersStr = /** @type {string} */ (cliFlags.extraHeaders);
-  // If not a JSON object, assume it's a path to a JSON file.
-  if (extraHeadersStr.substr(0, 1) !== '{') {
-    extraHeadersStr = fs.readFileSync(extraHeadersStr, 'utf-8');
+  if (cliFlags.extraHeaders) {
+    // TODO: LH.Flags.extraHeaders is actually a string at this point, but needs to be
+    // copied over to LH.Settings.extraHeaders, which is LH.Crdp.Network.Headers. Force
+    // the conversion here, but long term either the CLI flag or the setting should have
+    // a different name.
+    // @ts-ignore
+    let extraHeadersStr = /** @type {string} */ (cliFlags.extraHeaders);
+    // If not a JSON object, assume it's a path to a JSON file.
+    if (extraHeadersStr.substr(0, 1) !== '{') {
+      extraHeadersStr = fs.readFileSync(extraHeadersStr, 'utf-8');
+    }
+
+    cliFlags.extraHeaders = JSON.parse(extraHeadersStr);
   }
 
-  cliFlags.extraHeaders = JSON.parse(extraHeadersStr);
-}
+  if (cliFlags.precomputedLanternDataPath) {
+    const lanternDataStr = fs.readFileSync(cliFlags.precomputedLanternDataPath, 'utf8');
+    /** @type {LH.PrecomputedLanternData} */
+    const data = JSON.parse(lanternDataStr);
+    if (!data.additionalRttByOrigin || !data.serverResponseTimeByOrigin) {
+      throw new Error('Invalid precomputed lantern data file');
+    }
+
+    cliFlags.precomputedLanternData = data;
+  }
 
-/**
- * @return {Promise<LH.RunnerResult|void>}
- */
-async function begin() {
   if (cliFlags.printConfig) {
     const config = generateConfig(configJson, cliFlags);
     process.stdout.write(config.getPrintString());

lighthouse-cli/cli-flags.js

@@ -97,6 +97,8 @@ function getFlags(manualArgv) {
         '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',
         'extra-headers': 'Set extra HTTP Headers to pass with request',
+        'precomputed-lantern-data-path': 'Path to the file where lantern simulation data should be read from, overwriting the lantern observed estimates for RTT and server latency.',
+        'lantern-data-output-path': 'Path to the file where lantern simulation data should be written to, can be used in a future run with the `precomputed-lantern-data-path` flag.',
         'only-audits': 'Only run the specified audits',
         'only-categories': 'Only run the specified categories',
         'skip-audits': 'Run everything except these audits',
@@ -133,6 +135,8 @@ function getFlags(manualArgv) {
       .array('skipAudits')
       .array('output')
       .string('extraHeaders')
+      .string('precomputedLanternDataPath')
+      .string('lanternDataOutputPath')
 
       // default values
       .default('chrome-flags', '')

lighthouse-cli/index.js

@@ -6,4 +6,7 @@
  */
 'use strict';
 
-require('./bin.js').begin();
+require('./bin.js').begin().catch(err => {
+  process.stderr.write(err.stack);
+  process.exit(1);
+});

lighthouse-cli/run.js

@@ -9,14 +9,14 @@
 
 const path = require('path');
 
-const Printer = require('./printer');
+const Printer = require('./printer.js');
 const ChromeLauncher = require('chrome-launcher');
 
 const yargsParser = require('yargs-parser');
-const lighthouse = require('../lighthouse-core');
+const lighthouse = require('../lighthouse-core/index.js');
 const log = require('lighthouse-logger');
-const getFilenamePrefix = require('../lighthouse-core/lib/file-namer').getFilenamePrefix;
-const assetSaver = require('../lighthouse-core/lib/asset-saver');
+const getFilenamePrefix = require('../lighthouse-core/lib/file-namer.js').getFilenamePrefix;
+const assetSaver = require('../lighthouse-core/lib/asset-saver.js');
 
 const opn = require('opn');
 
@@ -120,6 +120,11 @@ function handleError(err) {
 async function saveResults(runnerResult, flags) {
   const cwd = process.cwd();
 
+  if (flags.lanternDataOutputPath) {
+    const devtoolsLog = runnerResult.artifacts.devtoolsLogs.defaultPass;
+    await assetSaver.saveLanternNetworkData(devtoolsLog, flags.lanternDataOutputPath);
+  }
+
   const shouldSaveResults = flags.auditMode || (flags.gatherMode === flags.auditMode);
   if (!shouldSaveResults) return;
   const {lhr, artifacts, report} = runnerResult;

lighthouse-cli/test/cli/__snapshots__/index-test.js.snap

@@ -1213,6 +1213,7 @@ Object {
     "output": Array [
       "html",
     ],
+    "precomputedLanternData": null,
     "skipAudits": null,
     "throttling": Object {
       "cpuSlowdownMultiplier": 4,
@@ -1342,6 +1343,7 @@ Object {
     "output": Array [
       "json",
     ],
+    "precomputedLanternData": null,
     "skipAudits": null,
     "throttling": Object {
       "cpuSlowdownMultiplier": 4,