feat: add waitForInspectableTarget option (fix #145)

README.md

@@ -77,6 +77,11 @@ npm install chrome-launcher
   // Default: 50
   maxConnectionRetries: number;
 
+  // (optional) Interval in ms, which defines whether and how long an inspectable target should be awaited.
+  // `0` means that list of inspectable targets will not be requested and awaited.
+  // Default: 0
+  waitForInspectableTarget: number;
+
   // (optional) A dict of environmental key value pairs to pass to the spawned chrome process.
   envVars: {[key: string]: string};
 };

package.json

@@ -25,6 +25,8 @@
     "is-wsl": "^2.1.0",
     "lighthouse-logger": "^1.0.0",
     "mkdirp": "0.5.1",
+    "phin": "^3.4.1",
+    "povtor": "^1.1.0",
     "rimraf": "^2.6.1"
   },
   "version": "0.13.0",

src/chrome-launcher.ts

@@ -8,6 +8,8 @@
 import * as childProcess from 'child_process';
 import * as fs from 'fs';
 import * as net from 'net';
+import * as phin from 'phin';
+import {retry} from 'povtor';
 import * as rimraf from 'rimraf';
 import * as chromeFinder from './chrome-finder';
 import {getRandomPort} from './random-port';
@@ -40,6 +42,7 @@ export interface Options {
   ignoreDefaultFlags?: boolean;
   connectionPollInterval?: number;
   maxConnectionRetries?: number;
+  waitForInspectableTarget?: number;
   envVars?: {[key: string]: string|undefined};
 }
 
@@ -112,6 +115,7 @@ class Launcher {
   private requestedPort?: number;
   private connectionPollInterval: number;
   private maxConnectionRetries: number;
+  private waitForInspectableTarget: number;
   private fs: typeof fs;
   private rimraf: RimrafModule;
   private spawn: typeof childProcess.spawn;
@@ -122,6 +126,7 @@ class Launcher {
   userDataDir?: string;
   port?: number;
   pid?: number;
+  getTargetRetryTimeout: number = 500;
 
   constructor(private opts: Options = {}, moduleOverrides: ModuleOverrides = {}) {
     this.fs = moduleOverrides.fs || fs;
@@ -138,6 +143,7 @@ class Launcher {
     this.ignoreDefaultFlags = defaults(this.opts.ignoreDefaultFlags, false);
     this.connectionPollInterval = defaults(this.opts.connectionPollInterval, 500);
     this.maxConnectionRetries = defaults(this.opts.maxConnectionRetries, 50);
+    this.waitForInspectableTarget = defaults(this.opts.waitForInspectableTarget, 0);
     this.envVars = defaults(opts.envVars, Object.assign({}, process.env));
 
     if (typeof this.opts.userDataDir === 'boolean') {
@@ -278,8 +284,26 @@ class Launcher {
     }
   }
 
+  getTargetList() {
+    return phin({
+      url: `http://127.0.0.1:${this.port}/json/list`,
+      parse: 'json'
+    });
+  }
+
+  waitForTarget() {
+    return retry({
+      action: this.getTargetList,
+      actionContext: this,
+      retryOnError: true,
+      retryTest: (response: phin.IResponse) => !response || !Array.isArray(response.body) || !response.body.length,
+      retryTimeout: this.getTargetRetryTimeout,
+      timeLimit: this.waitForInspectableTarget
+    }).promise;
+  }
+
   // resolves if ready, rejects otherwise
-  private isDebuggerReady(): Promise<{}> {
+  isDebuggerReady(): Promise<{}> {
     return new Promise((resolve, reject) => {
       const client = net.createConnection(this.port!);
       client.once('error', err => {
@@ -312,7 +336,21 @@ class Launcher {
         launcher.isDebuggerReady()
             .then(() => {
               log.log('ChromeLauncher', waitStatus + `${log.greenify(log.tick)}`);
-              resolve();
+              if (launcher.waitForInspectableTarget > 0) {
+                log.log('ChromeLauncher', 'Waiting for an inspectable target...');
+                launcher.waitForTarget()
+                  .then((response: phin.IResponse) => {
+                    log.log('ChromeLauncher', 'Received target list: %O', response.body);
+                    resolve(response.body);
+                  })
+                  .catch((reason: unknown) => {
+                    log.error('ChromeLauncher', `Cannot get target list. Reason: ${reason}`);
+                    reject(reason);
+                  });
+              }
+              else {
+                resolve();
+              }
             })
             .catch(err => {
               if (retries > launcher.maxConnectionRetries) {

test/chrome-launcher-test.ts

@@ -183,4 +183,126 @@ describe('Launcher', () => {
     const chromeInstance = new Launcher({chromePath: ''});
     chromeInstance.launch().catch(() => done());
   });
+
+  describe('waitForTarget method', () => {
+    function getChromeInstance(targetList: unknown, waitForInspectableTarget?: number) {
+      const chromeInstance = new Launcher({waitForInspectableTarget: typeof waitForInspectableTarget === 'number' ? waitForInspectableTarget : 100});
+      const getTargetListStub = stub(chromeInstance, 'getTargetList').returns(Promise.resolve(targetList));
+
+      return {
+        chromeInstance,
+        getTargetListStub
+      };
+    }
+
+    it('returns promise that is resolved with the same value as promise returned by getTargetList method', () => {
+      const response = {
+        body: ['test', 'list']
+      };
+      const {chromeInstance, getTargetListStub} = getChromeInstance(response);
+
+      return chromeInstance.waitForTarget().then((result) => {
+        assert.ok(getTargetListStub.calledOnce);
+        assert.strictEqual(result, response);
+      });
+    });
+
+    it('returns promise that is resolved with the same value as promise returned by getTargetList method after interval specified in waitForInspectableTarget option', () => {
+      const response = {
+        body: []
+      };
+      const waitTime = 90;
+      const {chromeInstance, getTargetListStub} = getChromeInstance(response, waitTime);
+      chromeInstance.getTargetRetryTimeout = 50;
+      const startTime = new Date().getTime();
+
+      return chromeInstance.waitForTarget().then((result) => {
+        assert.ok(getTargetListStub.callCount === 3);
+        assert.ok(new Date().getTime() - startTime > waitTime);
+        assert.strictEqual(result, response);
+      });
+    });
+
+    it('returns promise that is rejected with the same value as promise returned by getTargetList method after interval specified in waitForInspectableTarget option', () => {
+      const reason = 'No target';
+      const waitTime = 100;
+      const {chromeInstance, getTargetListStub} = getChromeInstance(Promise.reject(reason), waitTime);
+      chromeInstance.getTargetRetryTimeout = 40;
+      const startTime = new Date().getTime();
+
+      return chromeInstance.waitForTarget().catch((result) => {
+        assert.ok(getTargetListStub.callCount === 4);
+        assert.ok(new Date().getTime() - startTime > waitTime);
+        assert.strictEqual(result, reason);
+      });
+    });
+  });
+
+  describe('waitForInspectableTarget option', () => {
+    function getChromeInstance(options?: Options) {
+      const chromeInstance = new Launcher(options);
+      stub(chromeInstance, 'isDebuggerReady').returns(Promise.resolve());
+
+      return chromeInstance;
+    }
+
+    it('waitUntilReady does not call waitForTarget method when the option is not set', () => {
+      const chromeInstance = getChromeInstance();
+      const waitForTargetSpy = spy(chromeInstance, 'waitForTarget');
+
+      return chromeInstance.waitUntilReady().then(() => {
+        assert.ok(waitForTargetSpy.notCalled);
+      });
+    });
+
+    it('waitUntilReady does not call waitForTarget method when 0 is set for the option', () => {
+      const chromeInstance = getChromeInstance({waitForInspectableTarget: 0});
+      const waitForTargetSpy = spy(chromeInstance, 'waitForTarget');
+
+      return chromeInstance.waitUntilReady().then(() => {
+        assert.ok(waitForTargetSpy.notCalled);
+      });
+    });
+
+    it('waitUntilReady does not call waitForTarget method when negative value is set for the option', () => {
+      const chromeInstance = getChromeInstance({waitForInspectableTarget: -1});
+      const waitForTargetSpy = spy(chromeInstance, 'waitForTarget');
+
+      return chromeInstance.waitUntilReady().then(() => {
+        assert.ok(waitForTargetSpy.notCalled);
+      });
+    });
+
+    it('waitUntilReady calls waitForTarget method when the option is set', () => {
+      const chromeInstance = getChromeInstance({waitForInspectableTarget: 1000});
+      const response = {
+        body: [{
+          description: '',
+          devtoolsFrontendUrl: '/devtools/inspector.html?ws=127.0.0.1:54321/devtools/page/1C2C62A45591F2DECB9CC50E7C3B1FA5',
+          id: '1C2C62A45591F2DECB9CC50E7C3B1FA5',
+          title: '',
+          type: 'page',
+          url: 'about:blank',
+          webSocketDebuggerUrl: 'ws://127.0.0.1:54321/devtools/page/1C2C62A45591F2DECB9CC50E7C3B1FA5'
+        }]
+      };
+      const waitForTargetStub = stub(chromeInstance, 'waitForTarget').returns(Promise.resolve(response));
+
+      return chromeInstance.waitUntilReady().then((result) => {
+        assert.ok(waitForTargetStub.calledOnce);
+        assert.deepEqual(result, response.body);
+      });
+    });
+
+    it('waitUntilReady rejects when waitForTarget method returns rejected promise', () => {
+      const chromeInstance = getChromeInstance({waitForInspectableTarget: 1});
+      const reason = 'No targets';
+      const waitForTargetStub = stub(chromeInstance, 'waitForTarget').returns(Promise.reject(reason));
+
+      return chromeInstance.waitUntilReady().catch((result) => {
+        assert.ok(waitForTargetStub.calledOnce);
+        assert.strictEqual(result, reason);
+      });
+    });
+  });
 });

yarn.lock

@@ -87,6 +87,11 @@ camelcase@^5.0.0:
   resolved "https://registry.yarnpkg.com/camelcase/-/camelcase-5.3.1.tgz#e3c9b31569e106811df242f715725a1f4c494320"
   integrity sha512-L28STB170nwWS63UjtlEOE3dldQApaJXZkOI1uMFfzf3rRuPegHaHesyee+YxQ+W6SvRDQV6UrdOdRiR153wJg==
 
+centra@^2.2.1:
+  version "2.4.0"
+  resolved "https://registry.yarnpkg.com/centra/-/centra-2.4.0.tgz#53846f97db27705e9f90c46e0f824f6eb697e2d1"
+  integrity sha512-AWmF3EHNe/noJHviynZOrdnUuQzT5AMgl9nJPXGvnzGXrI2ZvNDrEcdqskc4EtQwt2Q1IggXb0OXy7zZ1Xvvew==
+
 chalk@^2.0.1:
   version "2.4.2"
   resolved "https://registry.yarnpkg.com/chalk/-/chalk-2.4.2.tgz#cd42541677a54333cf541a49108c1432b44c9424"
@@ -518,6 +523,18 @@ path-to-regexp@^1.7.0:
   dependencies:
     isarray "0.0.1"
 
+phin@^3.4.1:
+  version "3.4.1"
+  resolved "https://registry.yarnpkg.com/phin/-/phin-3.4.1.tgz#b023d14fa86fc6e4b40b6d0dfd5fe478c9c1bbb8"
+  integrity sha512-NkBCNRPxeyrgaPlWx4DHTAdca3s2LkvIBiiG6RoSbykcOtW/pA/7rUP/67FPIinvbo7h+HENST/vJ17LdRNUdw==
+  dependencies:
+    centra "^2.2.1"
+
+povtor@^1.1.0:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/povtor/-/povtor-1.1.0.tgz#bebe6618c0bcd0df55bd9f6dd2bebebb4d15c5a5"
+  integrity sha512-gUhd8L9iC4rSipLzx3mCInjusheig56wDrQLiwi5DH5FuumXJE0fEtvZNuheDqjXgMxARLoCz2erqOaa6Trgiw==
+
 require-directory@^2.1.1:
   version "2.1.1"
   resolved "https://registry.yarnpkg.com/require-directory/-/require-directory-2.1.1.tgz#8c64ad5fd30dab1c976e2344ffe7f792a6a6df42"