PWMetrics

Progressive web metrics at your fingertipz. 💅

CLI tool and lib to gather performance metrics via Lighthouse.

Documentation on these metrics in the works. If you hit bugs in the metrics collection, report at Lighthouse issues. How to use article

Install

$ yarn global add pwmetrics
# or
$ yarn add --dev pwmetrics

CLI Usage

$ pwmetrics <url> <flags>

pwmetrics http://example.com/

# --runs=n     Does n runs (eg. 3, 5), and reports the median run's numbers.
#              Median run selected by run with the median TTI.
pwmetrics http://example.com/ --runs=3

# --json       Reports json details to stdout.
pwmetrics http://example.com/ --json

# returns...
# {runs: [{
#   "timings": [
#     {
#       "name": "First Contentful Paint",
#       "value": 289.642
#     },
#     {
#       "name": "First Meaningful Paint",
#       "value": 289.6
#     },
#     ...

# --output-path       File path to save results.
pwmetrics http://example.com/ --output-path='pathToFile/file.json'

# --config        Provide configuration (defaults to `package.json`). See _Defining config_ below.
pwmetrics --config=pwmetrics-config.js

# --submit       Submit results to Google Sheets. See _Defining submit_ below.
pwmetrics --submit

# --upload       Upload Lighthouse traces to Google Drive. See _Defining upload_ below.
pwmetrics --upload

# --view       View Lighthouse traces, which were uploaded to Google Drive, in DevTools. See _Defining view_ below.
pwmetrics --view

##
## CLI options useful for CI
##

# --expectations  Assert metrics results against provides values. See _Defining expectations_ below.
pwmetrics --expectations

# --fail-on-error  Exit PWMetrics with an error status code after the first unfilled expectation.
pwmetrics --fail-on-error

Defining config

# run pwmetrics with config in package.json
pwmetrics --config

package.json

...
  "pwmetrics": {
    "url": "http://example.com/",
    // other configuration options
  }
...

# run pwmetrics with config in pwmetrics-config.js
pwmetrics --config=pwmetrics-config.js

pwmetrics-config.js

module.exports = {
  url: 'http://example.com/',
   // other configuration options. Read _All available configuration options_
}

All available configuration options

pwmetrics-config.js

const METRICS = require('pwmetrics/lib/metrics');

module.exports = {
  url: 'http://example.com/',
  flags: { // AKA feature flags
    runs: 3, // number or runs
    submit: true, // turn on submitting to Google Sheets
    upload: true, // turn on uploading to Google Drive
    view: true, // open uploaded traces to Google Drive in DevTools
    expectations: true, // turn on assertion metrics results against provides values
    json: true, // not required, set to true if you want json output
    outputPath: 'stdout', // not required, only needed if you have specified json output, can be "stdout" or a path
    chromePath: '/Applications/Google\ Chrome\ Canary.app/Contents/MacOS/Google\ Chrome\ Canary', //optional path to specific Chrome location
    chromeFlags: '', // custom flags to pass to Chrome. For a full list of flags, see http://peter.sh/experiments/chromium-command-line-switches/.
    // Note: pwmetrics supports all flags from Lighthouse
    showOutput: true, // not required, set to false for pwmetrics not output any console.log messages
    failOnError: false // not required, set to true if you want to fail the process on expectations errors
  },
  expectations: {
    // these expectations values are examples, for your cases set your own
    // it's not required to use all metrics, you can use just a few of them
    // Read _Available metrics_ where all keys are defined
    [METRICS.TTFCP]: {
      warn: '>=1500',
      error: '>=2000'
    },
    [METRICS.TTFMP]: {
      warn: '>=2000',
      error: '>=3000'
    },
    [METRICS.TTI]: {
      ...
    },
    [METRICS.TTFCPUIDLE]: {
      ...
    },
    [METRICS.SI]: {
      ...
    },
  },
  sheets: {
    type: 'GOOGLE_SHEETS', // sheets service type. Available types: GOOGLE_SHEETS
    options: {
      spreadsheetId: 'sheet_id',
      tableName: 'data',
      uploadMedian: false // not required, set to true if you want to upload only the median run
    }
  },
  clientSecret: {
    // Data object. Can be get
    // either
    // by (using everything in step 1 here)[https://developers.google.com/sheets/api/quickstart/nodejs#step_1_turn_on_the_api_name]
    //
    // example format:
    //
    // installed: {
    //   client_id: "sample_client_id",
    //   project_id: "sample_project_id",
    //   auth_uri: "https://accounts.google.com/o/oauth2/auth",
    //   token_uri: "https://accounts.google.com/o/oauth2/token",
    //   auth_provider_x509_cert_url: "https://www.googleapis.com/oauth2/v1/certs",
    //   client_secret: "sample_client_secret",
    //   redirect_uris: [
    //     "url",
    //     "http://localhost"
    //   ]
    // }
    //
    // or
    // by (using everything in step 1 here)[https://developers.google.com/drive/v3/web/quickstart/nodejs]
  }
}

Defining expectations

Recipes for using with CI

# run pwmetrics with config in package.json
pwmetrics --expectations

package.json

...
  "pwmetrics": {
    "url": "http://example.com/",
    "expectations": {
      ...
    }
  }
...

# run pwmetrics with config in pwmetrics-config.js
pwmetrics --expectations --config=pwmetrics-config.js

Defining submit

Submit results to Google Sheets

Instructions:

• Copy this spreadsheet.
• Copy the ID of the spreadsheet into the config as value of sheets.options.spreadsheetId property.
• Setup Google Developer project and get credentials. (everything in step 1 here)
• Take a client_secret and put it into the config as value of clientSecret property.

# run pwmetrics with config in package.json
pwmetrics --submit

# run pwmetrics with config in pwmetrics-config.js
pwmetrics --submit --config=pwmetrics-config.js

pwmetrics-config.js

module.exports = {
  'url': 'http://example.com/',
  'sheets': {
    ...
  },
  'clientSecret': {
    ...
  }
}

Defining upload

Upload Lighthouse traces to Google Drive

Instructions:

• Setup Google Developer project and get credentials. (everything in step 1 here)
• Take a client_secret and put it into the config as value of clientSecret property.

# run pwmetrics with config in package.json
pwmetrics --upload

# run pwmetrics with config in pwmetrics-config.js
pwmetrics --upload --config=pwmetrics-config.js

pwmetrics-config.js

module.exports = {
  'url': 'http://example.com/',
  'clientSecret': {
    ...
  }
}

View Lighthouse traces in timeline-viewer

Show Lighthouse traces in timeline-viewer.

Required to use upload flag

timeline-viewer - Shareable URLs for your Chrome DevTools Timeline traces.

# run pwmetrics with config in package.json
pwmetrics --upload --view

# run pwmetrics with config in your-own-file.js
pwmetrics --upload --view --config=your-own-file.js

pwmetrics-config.js

module.exports = {
  'url': 'http://example.com/',
  'clientSecret': {
    ...
  }
}

Available metrics:

All metrics now are stored in separate constant object located in pwmetrics/lib/metrics/metrics;

// lib/metrics/metrics.ts
{
  METRICS: {
    TTFCP: 'firstContentfulPaint',
    TTFMP: 'firstMeaningfulPaint',
    TTFCPUIDLE: 'firstCPUIdle',
    TTI: 'interactive',
    SI: 'speedIndex'
  }
}

Read article Performance metrics. What’s this all about? which is decoding this metrics.

API

const PWMetrics = require('pwmetrics');

const options = {
  flags: {
    runs: 3, // number or runs
    submit: true, // turn on submitting to Google Sheets
    upload: true, // turn on uploading to Google Drive
    view: true, // open uploaded traces to Google Drive in DevTools
    expectations: true, // turn on assertation metrics results against provides values
    chromeFlags: '--headless' // run in headless Chrome
  }
};

const pwMetrics = new PWMetrics('http://example.com/', options); // _All available configuration options_ can be used as `options`
pwMetrics.start(); // returns Promise

Options

Option	Type	Default	Description
flags*	Object	{ runs: 1, submit: false, upload: false, view: false, expectations: false, disableCpuThrottling: false, chromeFlags: '' }	Feature flags
expectations	Object	{}	See Defining expectations above.
sheets	Object	{}	See Defining submit above.
clientSecret	Object	{}	Client secrete data generated by Google API console. To setup Google Developer project and get credentials apply everything in step 1 here.

^*pwmetrics supports all flags from Lighthouse. See here for the complete list.

Recipes

• gulp

License

Apache 2.0. Google Inc.