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refactor of gather-runner to clarify lifecycle
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@brendankenny
brendankenny committed Aug 17, 2016
1 parent 2a4d99c commit 8c5e7d1
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Showing 4 changed files with 146 additions and 122 deletions.
196 changes: 102 additions & 94 deletions lighthouse-core/gather/gather-runner.js
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,35 @@
const log = require('../lib/log.js');
const Audit = require('../audits/audit');

/**
* Class that drives browser to load the page and runs gatherer lifecycle hooks.
* Execution sequence when GatherRunner.run() is called:
*
* 1. Setup
* A. driver.connect()
* B. GatherRunner.setupDriver()
* i. beginEmulation
* ii. cleanAndDisableBrowserCaches
* iii. forceUpdateServiceWorkers
*
* 2. For each pass in the config:
* A. GatherRunner.beforePass()
* i. all gatherer's beforePass()
* B. GatherRunner.pass()
* i. GatherRunner.loadPage()
* a. navigate to about:blank
* b. beginTrace & beginNetworkCollect (if requested)
* c. navigate to options.url (and wait for onload)
* ii. all gatherer's pass()
* C. GatherRunner.afterPass()
* i. endTrace & endNetworkCollect (if requested)
* ii. all gatherer's afterPass()
*
* 3. Teardown
* A. reloadForCleanStateIfNeeded
* B. driver.disconnect()
* C. collect all artifacts and return them
*/
class GatherRunner {
static loadPage(driver, options) {
// Since a Page.reload command does not let a service worker take over, we
Expand All @@ -27,46 +56,34 @@ class GatherRunner {
return driver.gotoURL('about:blank')
// Wait a bit for about:blank to "take hold" before switching back to the page.
.then(_ => new Promise((resolve, reject) => setTimeout(resolve, 300)))
// Begin tracing and network recording if required.
.then(_ => options.config.trace && driver.beginTrace())
.then(_ => options.config.network && driver.beginNetworkCollect())
// Navigate.
.then(_ => driver.gotoURL(options.url, {
waitForLoad: true,
disableJavaScript: !!options.disableJavaScript
}));
}

static setupDriver(driver, gatherers, options) {
static setupDriver(driver, options) {
log.log('status', 'Initializing…');
return new Promise((resolve, reject) => {
// Enable emulation.
if (options.flags.mobile) {
return resolve(driver.beginEmulation());
}

// noop if no mobile emulation
resolve();
}).then(_ => {
return driver.cleanAndDisableBrowserCaches();
}).then(_ => {
// Force SWs to update on load.
return driver.forceUpdateServiceWorkers();
});
}

static setupPass(options) {
const driver = options.driver;
const config = options.config;
let pass = Promise.resolve();

if (config.trace) {
pass = pass.then(_ => driver.beginTrace());
}

if (config.network) {
pass = pass.then(_ => driver.beginNetworkCollect());
}

return pass;
// Enable emulation if required.
return Promise.resolve(options.flags.mobile && driver.beginEmulation())
.then(_ => {
return driver.cleanAndDisableBrowserCaches();
}).then(_ => {
// Force SWs to update on load.
return driver.forceUpdateServiceWorkers();
});
}

/**
* Calls beforePass() on gatherers before navigation and before tracing has
* started (if requested).
* @param {!Object} options
* @return {!Promise}
*/
static beforePass(options) {
const config = options.config;
const gatherers = config.gatherers;
Expand All @@ -78,18 +95,24 @@ class GatherRunner {
}, Promise.resolve());
}

/**
* Navigates to requested URL and then runs pass() on gatherers while trace
* (if requested) is still being recorded.
* @param {!Object} options
* @return {!Promise}
*/
static pass(options) {
const driver = options.driver;
const config = options.config;
const gatherers = config.gatherers;
const gatherernames = gatherers.map(g => g.name).join(', ');
let pass = Promise.resolve();

if (config.loadPage) {
pass = pass.then(_ => {
const status = 'Loading page & waiting for onload';
const gatherernames = gatherers.map(g => g.name).join(', ');
log.log('status', status, gatherernames);
return this.loadPage(driver, options).then(_ => {
return GatherRunner.loadPage(driver, options).then(_ => {
log.log('statusEnd', status);
});
});
Expand All @@ -100,99 +123,85 @@ class GatherRunner {
}, pass);
}

/**
* Ends tracing and collects trace data (if requested for this pass), and runs
* afterPass() on gatherers with trace data passed in. Promise resolves with
* object containing trace and network data.
* @param {!Object} options
* @return {!Promise}
*/
static afterPass(options) {
const driver = options.driver;
const config = options.config;
const gatherers = config.gatherers;
const loadData = {traces: {}};
let pass = Promise.resolve();
let traceName = Audit.DEFAULT_TRACE;
if (config.traceName) {
traceName = config.traceName;
}

if (config.trace) {
pass = pass.then(_ => {
log.log('status', 'Retrieving trace');
return driver.endTrace().then(traceContents => {
// Before Chrome 54.0.2816 (codereview.chromium.org/2161583004),
// traceContents was an array of trace events. After this point,
// traceContents is an object with a traceEvents property. Normalize
// to new format.
if (Array.isArray(traceContents)) {
traceContents = {
traceEvents: traceContents
};
}

loadData.traces[traceName] = traceContents;
loadData.traceEvents = traceContents.traceEvents;
log.verbose('statusEnd', 'Retrieving trace');
});
return driver.endTrace();
}).then(traceContents => {
// Before Chrome 54.0.2816 (codereview.chromium.org/2161583004),
// traceContents was an array of trace events. After this point,
// traceContents is an object with a traceEvents property. Normalize
// to new format.
if (Array.isArray(traceContents)) {
traceContents = {
traceEvents: traceContents
};
}

const traceName = config.traceName || Audit.DEFAULT_TRACE;
loadData.traces[traceName] = traceContents;
loadData.traceEvents = traceContents.traceEvents;
log.verbose('statusEnd', 'Retrieving trace');
});
}

if (config.network) {
const status = 'Retrieving network records';
pass = pass.then(_ => {
const status = 'Retrieving network records';
log.log('status', status);
return driver.endNetworkCollect().then(networkRecords => {
loadData.networkRecords = networkRecords;
log.verbose('statusEnd', status);
});
return driver.endNetworkCollect();
}).then(networkRecords => {
loadData.networkRecords = networkRecords;
log.verbose('statusEnd', status);
});
}

return gatherers
.reduce((chain, gatherer) => {
return chain.then(_ => {
const status = `Retrieving: ${gatherer.name}`;
log.log('status', status);
return Promise.resolve(gatherer.afterPass(options, loadData)).then(ret => {
log.verbose('statusEnd', status);
return ret;
});
});
}, pass)
.then(_ => loadData);
pass = gatherers.reduce((chain, gatherer) => {
const status = `Retrieving: ${gatherer.name}`;
return chain.then(_ => {
log.log('status', status);
return gatherer.afterPass(options, loadData);
}).then(ret => {
log.verbose('statusEnd', status);
return ret;
});
}, pass);

// Resolve on loadData.
return pass.then(_ => loadData);
}

static run(passes, options) {
const driver = options.driver;
const tracingData = {traces: {}};

if (typeof options.url !== 'string' || options.url.length === 0) {
return Promise.reject(new Error('You must provide a url to the driver'));
}

if (typeof options.flags === 'undefined') {
options.flags = {};
}

// Default mobile emulation and page loading to true.
// The extension will switch these off initially.
if (typeof options.flags.mobile === 'undefined') {
options.flags.mobile = true;
}

if (typeof options.flags.loadPage === 'undefined') {
options.flags.loadPage = true;
}

passes = this.instantiateGatherers(passes);
passes = GatherRunner.instantiateGatherers(passes);

return driver.connect()
.then(_ => this.setupDriver(driver, 1, options))
.then(_ => GatherRunner.setupDriver(driver, options))

// Run each pass
.then(_ => {
return passes.reduce((chain, config) => {
const runOptions = Object.assign({}, options, {config});
return chain
.then(_ => this.setupPass(runOptions))
.then(_ => this.beforePass(runOptions))
.then(_ => this.pass(runOptions))
.then(_ => this.afterPass(runOptions))
.then(_ => GatherRunner.beforePass(runOptions))
.then(_ => GatherRunner.pass(runOptions))
.then(_ => GatherRunner.afterPass(runOptions))
.then(loadData => {
// Merge pass trace and network data into tracingData.
config.trace && Object.assign(tracingData.traces, loadData.traces);
Expand All @@ -207,7 +216,6 @@ class GatherRunner {
log.log('status', 'Disconnecting from browser...');
driver.disconnect();
});
return undefined;
})
.then(_ => {
// Collate all the gatherer results.
Expand Down
17 changes: 17 additions & 0 deletions lighthouse-core/runner.js
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,23 @@ const path = require('path');

class Runner {
static run(driver, opts) {
// Clean opts input.
if (typeof opts.url !== 'string' || opts.url.length === 0) {
return Promise.reject(new Error('You must provide a url to the driver'));
}

opts.flags = opts.flags || {};

// Default mobile emulation and page loading to true.
// The extension will switch these off initially.
if (typeof opts.flags.mobile === 'undefined') {
opts.flags.mobile = true;
}

if (typeof opts.flags.loadPage === 'undefined') {
opts.flags.loadPage = true;
}

const config = opts.config;

// Check that there are passes & audits...
Expand Down
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