Node script for running a test with WebPagetest and writing the results to InfluxDB and to file

webpagetest.js

// Imports
const WebPageTest = require("webpagetest");
const fs = require("fs");
var download = require("download-file"); // Install download-file https://www.npmjs.com/package/download-file
const Influx = require("influx"); // Download and install InfluxDB https://v2.docs.influxdata.com/v2.0/get-started/
const influx = new Influx.InfluxDB({
  host: "localhost",
  database: "webpagetest",
  port: 8086
});
module.exports = influx;

// Variables that are input from a command to run this node script, 
// e.g. 'node webpagetest.js "https://www.example.com/" example-home "3GFast" true'
let testURL = process.argv[2];
let pageName = process.argv[3];
let connectivityProfile = process.argv[4];
let mobileEmulationBool = process.argv[5];

// Paths for the file outputs
let path = "./results/";
let videoDownloadURL = "https://www.webpagetest.org/video/download.php?id=";
let filmstripURL_start =
  "https://www.webpagetest.org/video/filmstrip.php?tests=";
let filmstripURL_end =
  "-r:1-c:0&thumbSize=200&ival=500&end=visual&text=ffffff&bg=000000";

// Other variables
let testStart = new Date().toISOString();
const key = "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"; // Enter your WebPagetest API key from https://www.webpagetest.org/getkey.php
const wpt = new WebPageTest("www.webpagetest.org", key);

const testOpts = {
  emulateMobile: mobileEmulationBool,
  location: "ec2-eu-central-1", // Or set a different test location
  firstViewOnly: false,
  connectivity: connectivityProfile,
  pollResults: 5,
  video: true,
  lighthouse: true
};

const script = wpt.scriptToString([
  { navigate: testURL },
  "waitForComplete"
]);


// Run a test on WebPagetest
console.log(
  `${testStart}:\nStarting Webpagetest for ${testURL} with ${connectivityProfile} connectivity...`
);

wpt.runTest(script, testOpts, (err, result) => {
  if (err) {
    console.log("Can't run the test for some reason.");
    throw err;
  }
  let date = result.data.completed;
  let fileName = path + date + " - " + pageName + ".json";
  let testID = result.data.id;

  let stats = JSON.stringify(result.data, null, 2);

  // Metrics
  let firstView = result.data.median.firstView;
  let firstMeaningfulPaint = firstView.firstMeaningfulPaint,
    loadTime = firstView.loadTime,
    TTI = firstView["lighthouse.Performance.interactive"],
    bytesInDoc = firstView.bytesInDoc,
    requestsDoc = firstView.requestsDoc,
    fullyLoaded = firstView.fullyLoaded,
    timeToFirstByte = firstView.TTFB,
    firstContentfulPaint =
      firstView["lighthouse.Performance.first-contentful-paint"],
    wptSpeedIndex = firstView["lighthouse.Performance.speed-index"],
    bytesHTML = firstView.breakdown.html.bytes,
    bytesJS = firstView.breakdown.js.bytes,
    bytesCSS = firstView.breakdown.css.bytes,
    bytesImages = firstView.breakdown.image.bytes,
    bytesFonts = firstView.breakdown.font.bytes;

    
  // Log some metrics to console
  let metrics = [loadTime, timeToFirstByte, firstLayout, firstContentfulPaint, TTI, SpeedIndex, lastPaintedHero, firstCPUIdle];
  for (metric of metrics) {
    console.log(metric);
  }

  
  // Write data to InfluxDB
  date *= 1000000000;

  influx
    .writePoints([
      {
        measurement: "webpagetest",
        tags: {
          pageName: pageName,
          run: 1
        },
        fields: {
          timeToInteractive: TTI,
          bytesInDoc: bytesInDoc,
          fullyLoaded: fullyLoaded,
          requestsDoc: requestsDoc,
          loadTime: loadTime,
          timeToFirstByte: timeToFirstByte,
          firstContentfulPaint: firstContentfulPaint,
          performance: performance,
          speedIndex: wptSpeedIndex,
          bytesHTML: bytesHTML,
          bytesJS: bytesJS,
          bytesCSS: bytesCSS,
          bytesImages: bytesImages,
          bytesFonts: bytesFonts
        },
        timestamp: date
      }
    ])
    .then(() => {
      return influx.query(`
        select * from webpagetest
        order by time desc
        `);
    })
    .catch(err => {
      console.error(`Error creating Influx database!`);
    });


  // Save test results as JSON file
  fs.writeFile(fileName, stats, err => {
    if (err) throw err;
    console.log("Data for " + pageName + "written to file: " + fileName);
  });


  // Optionally create a video
  var videoOptions = {
    directory: path,
    filename: date + " - " + pageName + ".mp4"
  };

  wpt.createVideo(testID, testOpts, (err, data) => {
    console.log(err || data);
    let videoId = data.data.videoId;
    videoDownloadURL += videoId;

    setTimeout(function() {
      download(videoDownloadURL, videoOptions, function(err) {
        if (err) throw err;
        console.log(
          "Video download URL for " + pageName + ": " + videoDownloadURL
        );
      });
    }, 5000);

    // Optionally download the filmstrip
    var filmstripOptions = {
      directory: path,
      filename: date + " - " + pageName + ".png"
    };

    var filmstripURL = filmstripURL_start + testID + filmstripURL_end;
    download(filmstripURL, filmstripOptions, function(err) {
      if (err) throw err;
      console.log(
        "Filmstrip download URL for " + pageName + ": " + filmstripURL
      );
    });
  });
  
});