core(lhr): expose environment info

lighthouse-core/gather/driver.js

@@ -107,6 +107,13 @@ class Driver {
     return this.evaluateAsync('navigator.userAgent');
   }
 
+  /**
+   * @return {Promise<number>}
+   */
+  getBenchmarkIndex() {
+    return this.evaluateAsync(`(${pageFunctions.ultradumbBenchmark.toString()})()`);
+  }
+
   /**
    * @return {Promise<void>}
    */

lighthouse-core/gather/gather-runner.js

@@ -374,7 +374,9 @@ class GatherRunner {
     return {
       fetchTime: (new Date()).toJSON(),
       LighthouseRunWarnings: [],
-      UserAgent: await options.driver.getUserAgent(),
+      HostUserAgent: await options.driver.getUserAgent(),
+      NetworkUserAgent: '', // updated later
+      BenchmarkIndex: await options.driver.getBenchmarkIndex(),
       traces: {},
       devtoolsLogs: {},
       settings: options.settings,
@@ -420,6 +422,16 @@ class GatherRunner {
         // Save devtoolsLog, but networkRecords are discarded and not added onto artifacts.
         baseArtifacts.devtoolsLogs[passConfig.passName] = passData.devtoolsLog;
 
+        const userAgentEntry = passData.devtoolsLog.find(entry =>
+          entry.method === 'Network.requestWillBeSent' &&
+          !!entry.params.request.headers['User-Agent']
+        );
+
+        if (userAgentEntry && !baseArtifacts.NetworkUserAgent) {
+          // @ts-ignore - guaranteed to exist by the find above
+          baseArtifacts.NetworkUserAgent = userAgentEntry.params.request.headers['User-Agent'];
+        }
+
         // If requested by config, save pass's trace.
         if (passData.trace) {
           baseArtifacts.traces[passConfig.passName] = passData.trace;

lighthouse-core/lib/page-functions.js

@@ -57,7 +57,6 @@ function registerPerformanceObserverInPage() {
   window.____lhPerformanceObserver = observer;
 }
 
-
 /**
  * Used by _waitForCPUIdle and executed in the context of the page, returns time since last long task.
  */
@@ -114,7 +113,35 @@ function getElementsInDocument(selector) {
 function getOuterHTMLSnippet(element) {
   const reOpeningTag = /^.*?>/;
   const match = element.outerHTML.match(reOpeningTag);
-  return match && match[0] || '';
+  return (match && match[0]) || '';
+}
+
+/**
+ * Computes a memory/CPU performance benchmark index to determine rough device class.
+ * @see https://docs.google.com/spreadsheets/d/1E0gZwKsxegudkjJl8Fki_sOwHKpqgXwt8aBAfuUaB8A/edit?usp=sharing
+ *
+ * The benchmark creates a string of length 100,000 in a loop.
+ * The returned index is the number of numbers per second the string can be created.
+ *
+ *  - 750+ is a desktop-class device, iPhone X, etc
+ *  - 300+ is a high-end Android phone, Galaxy S8, low-end Chromebook, etc
+ *  - 75+ is a mid-tier Android phone, Nexus 5X, etc
+ *  - <75 is a budget Android phone, Alcatel Ideal, Galaxy J2, etc
+ */
+/* istanbul ignore next */
+function ultradumbBenchmark() {
+  const start = Date.now();
+  let iterations = 0;
+
+  while (Date.now() - start < 500) {
+    let s = ''; // eslint-disable-line no-unused-vars
+    for (let j = 0; j < 100000; j++) s += 'a';
+
+    iterations++;
+  }
+
+  const durationInSeconds = (Date.now() - start) / 1000;
+  return iterations / durationInSeconds;
 }
 
 module.exports = {
@@ -123,4 +150,5 @@ module.exports = {
   checkTimeSinceLastLongTask,
   getElementsInDocument,
   getOuterHTMLSnippet,
+  ultradumbBenchmark,
 };

lighthouse-core/report/html/renderer/report-renderer.js

@@ -115,8 +115,14 @@ class ReportRenderer {
       {name: 'URL', description: report.finalUrl},
       {name: 'Fetch time', description: Util.formatDateTime(report.fetchTime)},
       ...envValues,
-      {name: 'User agent', description: report.userAgent},
+      {name: 'User agent (host)', description: report.userAgent},
+      {name: 'User agent (network)', description: report.environment &&
+        report.environment.networkUserAgent},
+      {name: 'CPU/Memory Power', description: report.environment &&
+        report.environment.benchmarkIndex.toFixed(0)},
     ].forEach(runtime => {
+      if (!runtime.description) return;
+
       const item = this._dom.cloneTemplate('#tmpl-lh-env__items', env);
       this._dom.find('.lh-env__name', item).textContent = `${runtime.name}:`;
       this._dom.find('.lh-env__description', item).textContent = runtime.description;

lighthouse-core/runner.js

@@ -122,7 +122,12 @@ class Runner {
 
       /** @type {LH.Result} */
       const lhr = {
-        userAgent: artifacts.UserAgent,
+        userAgent: artifacts.HostUserAgent,
+        environment: {
+          networkUserAgent: artifacts.NetworkUserAgent,
+          hostUserAgent: artifacts.HostUserAgent,
+          benchmarkIndex: artifacts.BenchmarkIndex,
+        },
         lighthouseVersion,
         fetchTime: artifacts.fetchTime,
         requestedUrl: requestedUrl,

lighthouse-core/test/gather/fake-driver.js

@@ -9,6 +9,9 @@ module.exports = {
   getUserAgent() {
     return Promise.resolve('Fake user agent');
   },
+  getBenchmarkIndex() {
+    return Promise.resolve(125.2);
+  },
   connect() {
     return Promise.resolve();
   },

lighthouse-core/test/gather/gather-runner-test.js

@@ -106,16 +106,37 @@ describe('GatherRunner', function() {
     });
   });
 
-  it('collects user agent as an artifact', () => {
+  it('collects benchmark as an artifact', async () => {
     const url = 'https://example.com';
     const driver = fakeDriver;
     const config = new Config({});
     const settings = {};
     const options = {url, driver, config, settings};
 
-    return GatherRunner.run([], options).then(results => {
-      assert.equal(results.UserAgent, 'Fake user agent', 'did not find expected user agent string');
-    });
+    const results = await GatherRunner.run([], options);
+    expect(Number.isFinite(results.BenchmarkIndex)).toBeTruthy();
+  });
+
+  it('collects host user agent as an artifact', async () => {
+    const url = 'https://example.com';
+    const driver = fakeDriver;
+    const config = new Config({});
+    const settings = {};
+    const options = {url, driver, config, settings};
+
+    const results = await GatherRunner.run([], options);
+    expect(results.HostUserAgent).toEqual('Fake user agent');
+  });
+
+  it('collects network user agent as an artifact', async () => {
+    const url = 'https://example.com';
+    const driver = fakeDriver;
+    const config = new Config({passes: [{}]});
+    const settings = {};
+    const options = {url, driver, config, settings};
+
+    const results = await GatherRunner.run(config.passes, options);
+    expect(results.NetworkUserAgent).toContain('Mozilla');
   });
 
   it('collects requested and final URLs as an artifact', () => {

lighthouse-core/test/results/artifacts/artifacts.json

@@ -1,6 +1,8 @@
 {
   "LighthouseRunWarnings": [],
-  "UserAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3358.0 Safari/537.36",
+  "BenchmarkIndex": 1000,
+  "HostUserAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3358.0 Safari/537.36",
+  "NetworkUserAgent": "Mozilla/5.0 (Linux; Android 6.0.1; Nexus 5 Build/MRA58N) AppleWebKit/537.36(KHTML, like Gecko) Chrome/66.0.3359.30 Mobile Safari/537.36",
   "fetchTime": "2018-03-13T00:55:45.840Z",
   "URL": {
     "requestedUrl": "http://localhost:10200/dobetterweb/dbw_tester.html",

lighthouse-core/test/results/sample_v2.json

@@ -1,5 +1,10 @@
 {
   "userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3358.0 Safari/537.36",
+  "environment": {
+    "networkUserAgent": "Mozilla/5.0 (Linux; Android 6.0.1; Nexus 5 Build/MRA58N) AppleWebKit/537.36(KHTML, like Gecko) Chrome/66.0.3359.30 Mobile Safari/537.36",
+    "hostUserAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3358.0 Safari/537.36",
+    "benchmarkIndex": 1000
+  },
   "lighthouseVersion": "3.0.3",
   "fetchTime": "2018-03-13T00:55:45.840Z",
   "requestedUrl": "http://localhost:10200/dobetterweb/dbw_tester.html",

typings/artifacts.d.ts

@@ -23,8 +23,12 @@ declare global {
       fetchTime: string;
       /** A set of warnings about unexpected things encountered while loading and testing the page. */
       LighthouseRunWarnings: string[];
-      /** The user agent string of the version of Chrome that was used by Lighthouse. */
-      UserAgent: string;
+      /** The user agent string of the version of Chrome used. */
+      HostUserAgent: string;
+      /** The user agent string that Lighthouse used to load the page. */
+      NetworkUserAgent: string;
+      /** The benchmark index that indicates rough device class. */
+      BenchmarkIndex: number;
       /** A set of page-load traces, keyed by passName. */
       traces: {[passName: string]: Trace};
       /** A set of DevTools debugger protocol records, keyed by passName. */

typings/lhr.d.ts

@@ -16,6 +16,12 @@ declare global {
       [varName: string]: string;
     }
 
+    export interface Environment {
+      hostUserAgent: string;
+      networkUserAgent: string;
+      benchmarkIndex: number;
+    }
+
     /**
      * The full output of a Lighthouse run.
      */
@@ -43,6 +49,8 @@ declare global {
       runWarnings: string[];
       /** The User-Agent string of the browser used run Lighthouse for these results. */
       userAgent: string;
+      /** Information about the environment in which Lighthouse was run. */
+      environment: Environment;
       /** Execution timings for the Lighthouse run */
       timing: {total: number, [t: string]: number};
       /** The record of all formatted string locations in the LHR and their corresponding source values. */