291 lines
8.5 KiB
JavaScript
291 lines
8.5 KiB
JavaScript
const child_process = require('child_process');
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const constants = require('../../constants');
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const path = require('path');
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const utils = require('../../utils/utils');
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let processCount = 1;
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class ProcessLauncher {
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/**
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* Constructor of ProcessLauncher. Forks the module and sets up the message handling
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* @param {Object} options Options tp start the process
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* * modulePath {String} Absolute path to the module to fork
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* * logger {Object} Logger
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* * events {Function} Events Emitter instance
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* @return {ProcessLauncher} The ProcessLauncher instance
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*/
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constructor(options) {
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this.name = options.name || path.basename(options.modulePath);
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if (this._isDebug()) {
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const childOptions = {stdio: 'pipe', execArgv: ['--inspect-brk=' + (60000 + processCount)]};
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processCount++;
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this.process = child_process.fork(options.modulePath, [], childOptions);
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} else {
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this.process = child_process.fork(options.modulePath);
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}
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this.logger = options.logger;
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this.events = options.events;
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this.silent = options.silent;
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this.exitCallback = options.exitCallback;
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this.embark = options.embark;
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this.logs = [];
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this.subscriptions = {};
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this._subscribeToMessages();
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if (this.embark) {
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this._registerAsPlugin();
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}
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}
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_isDebug() {
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const argvString= process.execArgv.join();
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return argvString.includes('--debug') || argvString.includes('--inspect');
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}
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// Subscribes to messages from the child process and delegates to the right methods
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_subscribeToMessages() {
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const self = this;
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this.process.on('message', (msg) => {
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if (msg.error) {
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self.logger.error(msg.error);
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}
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if (msg.result === constants.process.log) {
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return self._handleLog(msg);
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}
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if (msg.event) {
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return self._handleEvent(msg);
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}
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self._checkSubscriptions(msg);
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});
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this.process.on('exit', (code) => {
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if (self.exitCallback) {
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return self.exitCallback(code);
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}
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if (code) {
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this.logger.info(`Child Process ${this.name} exited with code ${code}`);
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}
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});
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}
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_registerAsPlugin() {
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const self = this;
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const apiRoute = '/embark-api/process-logs/' + self.name;
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self.embark.registerAPICall(
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'ws',
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apiRoute,
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(ws, _req) => {
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self.events.on('process-log-' + self.name, function(id, log) {
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ws.send(JSON.stringify(Object.assign(log, {id})), () => {});
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});
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}
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);
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self.embark.registerAPICall(
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'get',
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apiRoute,
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(_req, res) => {
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let limit = parseInt(req.query.limit, 10);
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if(!Number.isInteger(limit)) limit = 0;
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const result = self.logs.map((log, id) => Object.assign(log, {id})).slice(limit);
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res.send(JSON.stringify(result));
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}
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);
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}
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// Translates logs from the child process to the logger
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_handleLog(msg) {
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// Sometimes messages come in with line breaks, so we need to break them up accordingly.
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let processedMessages = [];
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// Ensure that `msg.message` is an array, so we process this consistently. Sometimes it
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// is an Array, sometimes it is a string.
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if(typeof msg.message === 'string') {
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processedMessages = [msg.message];
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} else {
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msg.message.forEach(message => {
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let lines = message.split("\n");
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lines.forEach(line => processedMessages.push(line));
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});
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}
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const timestamp = new Date().getTime();
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processedMessages.forEach((message) => {
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const log = {
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msg: message,
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msg_clear: message.stripColors,
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logLevel: msg.logLevel,
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name: this.name,
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timestamp
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};
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const id = this.logs.push(log) - 1;
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this.events.emit(`process-log-${this.name}`, id, log);
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if (this.silent && msg.type !== 'error') {
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return;
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}
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if (this.logger[msg.type]) {
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return this.logger[msg.type](utils.normalizeInput(message));
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}
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this.logger.debug(utils.normalizeInput(message));
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});
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}
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// Handle event calls from the child process
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_handleEvent(msg) {
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const self = this;
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if (!self.events[msg.event]) {
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self.logger.warn('Unknown event method called: ' + msg.event);
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return;
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}
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if (!msg.args || !Array.isArray(msg.args)) {
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msg.args = [];
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}
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// Add callback in the args
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msg.args.push((result) => {
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self.process.send({
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event: constants.process.events.response,
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result,
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eventId: msg.eventId
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});
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});
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self.events[msg.event](msg.requestName, ...msg.args);
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}
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// Looks at the subscriptions to see if there is a callback to call
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_checkSubscriptions(msg) {
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const messageKeys = Object.keys(msg);
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const subscriptionsKeys = Object.keys(this.subscriptions);
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let subscriptionsForKey;
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let messageKey;
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// Find if the message contains a key that we are subscribed to
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messageKeys.some(_messageKey => {
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return subscriptionsKeys.some(subscriptionKey => {
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if (_messageKey === subscriptionKey) {
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subscriptionsForKey = this.subscriptions[subscriptionKey];
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messageKey = _messageKey;
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return true;
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}
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return false;
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});
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});
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if (subscriptionsForKey) {
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// Find if we are subscribed to one of the values
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let subsIndex = [];
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const subscriptionsForValue = subscriptionsForKey.filter((sub, index) => {
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if (msg[messageKey] === sub.value) {
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subsIndex.push(index);
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return true;
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}
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return false;
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});
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if (subscriptionsForValue.length) {
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// We are subscribed to that message, call the callback
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subscriptionsForValue.forEach((subscription, index) => {
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subscription.callback(msg);
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if (subscription.once) {
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// Called only once, we can remove it
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subscription = null;
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this.subscriptions[messageKey].splice(subsIndex[index], 1);
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}
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});
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}
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}
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}
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/**
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* Subscribe to a message using a key-value pair
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* @param {String} key Message key to subscribe to
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* @param {String} value Value that the above key must have for the callback to be called
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* @param {Function} callback callback(response)
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* @return {void}
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*/
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on(key, value, callback) {
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if (this.subscriptions[key]) {
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this.subscriptions[key].push({value, callback});
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return;
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}
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this.subscriptions[key] = [{value, callback}];
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}
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/**
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* Same as .on, but only triggers once
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* @param {String} key Message key to subscribe to
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* @param {String} value Value that the above key must have for the callback to be called
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* @param {Function} callback callback(response)
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* @return {void}
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*/
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once(key, value, callback) {
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const obj = {value, callback, once: true};
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if (this.subscriptions[key]) {
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this.subscriptions[key].push(obj);
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return;
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}
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this.subscriptions[key] = [obj];
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}
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/**
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* Unsubscribes from a previously subscribed key-value pair (or key if no value)
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* @param {String} key Message key to unsubscribe
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* @param {String} value [Optional] Value of the key to unsubscribe
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* If there is no value, unsubscribes from all the values of that key
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* @return {void}
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*/
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unsubscribeTo(key, value) {
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if (!value) {
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this.subscriptions[key] = [];
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}
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if (this.subscriptions[key]) {
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this.subscriptions[key].filter((val, index) => {
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if (val.value === value) {
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this.subscriptions[key].splice(index, 1);
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}
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});
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}
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}
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/**
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* Unsubscribes from all subscriptions
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* @return {void}
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*/
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unsubscribeToAll() {
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this.subscriptions = {};
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}
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/**
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* Sends a message to the child process. Same as ChildProcess.send()
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* @params {Object} message Message to send
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* For other parameters, see:
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* https://nodejs.org/api/child_process.html#child_process_subprocess_send_message_sendhandle_options_callback
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* @return {void}
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*/
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send() {
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if (!this.process.connected) {
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return false;
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}
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return this.process.send(...arguments);
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}
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/**
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* Disconnects the child process. It will exit on its own
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* @return {void}
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*/
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disconnect() {
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this.process.disconnect();
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}
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/**
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* Kills the child process
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* https://nodejs.org/api/child_process.html#child_process_subprocess_kill_signal
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* @return {void}
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*/
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kill() {
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this.process.kill(...arguments);
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}
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}
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module.exports = ProcessLauncher;
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