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Always launch a new process for the UA service.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,134 @@ | ||
| /* | ||
| Copyright 2016 Mozilla | ||
| Licensed under the Apache License, Version 2.0 (the "License"); you may not use | ||
| this file except in compliance with the License. You may obtain a copy of the | ||
| License at http://www.apache.org/licenses/LICENSE-2.0 | ||
| Unless required by applicable law or agreed to in writing, software distributed | ||
| under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR | ||
| CONDITIONS OF ANY KIND, either express or implied. See the License for the | ||
| specific language governing permissions and limitations under the License. | ||
| */ | ||
|
|
||
| import path from 'path'; | ||
| import EventEmitter from 'events'; | ||
| import WebSocket from 'ws'; | ||
| import request from 'request'; | ||
| import { setTimeout } from 'timers'; | ||
| import childProcess from 'child_process'; | ||
| import * as endpoints from './constants/endpoints'; | ||
|
|
||
| function uaRequest(service, options) { | ||
| return new Promise((resolve, reject) => { | ||
| request[options.method.toLowerCase()]({ | ||
| url: `${endpoints.UA_SERVICE_HTTP}${service}`, | ||
| headers: { | ||
| Accept: 'application/json', | ||
| 'Content-Type': 'application/json', | ||
| }, | ||
| }, (err, response, body) => { | ||
| if (err) { | ||
| reject(err); | ||
| return; | ||
| } | ||
|
|
||
| resolve(JSON.parse(body)); | ||
| }); | ||
| }); | ||
| } | ||
|
|
||
| class UserAgent extends EventEmitter { | ||
| constructor(ws, clientCount) { | ||
| super(); | ||
|
|
||
| this.ws = ws; | ||
| this.clientCount = clientCount; | ||
|
|
||
| this.ws.on('message', (data) => { | ||
| data = JSON.parse(data); | ||
| const message = data.message; | ||
| delete data.message; | ||
| this.emit(message, data); | ||
| }); | ||
| } | ||
|
|
||
| startSession() { | ||
| return uaRequest('/session/start', { | ||
| method: 'POST', | ||
| }); | ||
| } | ||
| } | ||
|
|
||
| const timeout = (ms) => new Promise(resolve => setTimeout(resolve, ms)); | ||
|
|
||
| function startService() { | ||
| // Start a UA service | ||
| const exec = 'node'; | ||
| const args = ['server.js']; | ||
|
|
||
| console.log('Starting UA process'); | ||
| childProcess.spawn(exec, args, { | ||
| detached: true, | ||
| cwd: path.join(__dirname, '..', 'main'), | ||
| }); | ||
| } | ||
|
|
||
| function attemptConnect() { | ||
| return new Promise((resolve, reject) => { | ||
| const ws = new WebSocket(`${endpoints.UA_SERVICE_WS}`); | ||
|
|
||
| ws.on('open', () => { | ||
| console.log('Connected to UA process'); | ||
|
|
||
| // The first message should be protocol information | ||
| ws.once('message', (data) => { | ||
| data = JSON.parse(data); | ||
|
|
||
| if (data.message !== 'protocol' || data.version !== 'v1') { | ||
| console.error(`Incorrect message ${JSON.stringify(data)}`); | ||
| reject(); | ||
| return; | ||
| } | ||
| resolve(new UserAgent(ws, data.clientCount)); | ||
| }); | ||
| }); | ||
|
|
||
| ws.on('error', (e) => { | ||
| reject(e); | ||
| }); | ||
| }); | ||
| } | ||
|
|
||
| async function backoffConnect() { | ||
| let timedout = false; | ||
| const timer = setTimeout(() => timedout = true, 5000); | ||
| let delay = 200; | ||
|
|
||
| while (!timedout) { | ||
| try { | ||
| const ua = await attemptConnect(); | ||
| clearTimeout(timer); | ||
| return ua; | ||
| } catch (e) { | ||
| await timeout(delay); | ||
| delay *= 2; | ||
| } | ||
| } | ||
|
|
||
| throw new Error('Unable to connect to the UA service.'); | ||
| } | ||
|
|
||
| export default { | ||
| async connect() { | ||
| console.log('Attempting to connect'); | ||
| try { | ||
| return await attemptConnect(); | ||
| } catch (e) { | ||
| if (e.code === 'ECONNREFUSED') { | ||
| startService(); | ||
| return await backoffConnect(); | ||
| } | ||
| throw e; | ||
| } | ||
| }, | ||
| }; |
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