move process files into processes folder
This commit is contained in:
Iuri Matias
Pascal Precht
parent
d459a83d28
commit
326defc2f4
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@ -0,0 +1,55 @@
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const uuid = require('uuid/v1');
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const constants = require('../constants');
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class Events {
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/**
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* Constructs an event wrapper for processes.
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* Handles sending an event message to the parent process and waiting for its response
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* No need to create an instance of eventsWrapper for your own process, just extend ProcessWrapper
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* Then, you an use `this.events.[on|request]` with the usual parameters you would use
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*/
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constructor() {
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this.subscribedEvents = {};
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this.listenToParentProcess();
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}
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listenToParentProcess() {
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process.on('message', (msg) => {
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if (!msg.event || msg.event !== constants.process.events.response) {
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return;
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}
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if (!this.subscribedEvents[msg.eventId]) {
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return;
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}
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this.subscribedEvents[msg.eventId](msg.result);
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});
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}
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sendEvent() {
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const eventType = arguments[0];
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const requestName = arguments[1];
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let args = [].slice.call(arguments, 2);
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const eventId = uuid();
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this.subscribedEvents[eventId] = args[args.length - 1];
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args = args.splice(0, args.length - 2);
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process.send({
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event: eventType,
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requestName,
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args,
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eventId: eventId
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});
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}
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on() {
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this.sendEvent(constants.process.events.on, ...arguments);
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}
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request() {
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this.sendEvent(constants.process.events.request, ...arguments);
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}
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}
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module.exports = Events;
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@ -0,0 +1,218 @@
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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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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 = path.basename(options.modulePath);
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this.process = child_process.fork(options.modulePath);
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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.subscriptions = {};
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this._subscribeToMessages();
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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.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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// Translates logs from the child process to the logger
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_handleLog(msg) {
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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(msg.message));
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}
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this.logger.debug(utils.normalizeInput(msg.message));
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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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@ -0,0 +1,93 @@
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const constants = require('../constants');
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const Events = require('./eventsWrapper');
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// Override process.chdir so that we have a partial-implementation PWD for Windows
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const realChdir = process.chdir;
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process.chdir = (...args) => {
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if (!process.env.PWD) {
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process.env.PWD = process.cwd();
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}
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realChdir(...args);
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};
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class ProcessWrapper {
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/**
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* Class from which process extend. Should not be instantiated alone.
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* Manages the log interception so that all console.* get sent back to the parent process
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* Also creates an Events instance. To use it, just do `this.events.[on|request]`
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*
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* @param {Options} _options Nothing for now
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*/
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constructor(_options) {
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this.interceptLogs();
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this.events = new Events();
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this.pingParent();
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}
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// Ping parent to see if it is still alive. Otherwise, let's die
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pingParent() {
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const self = this;
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self.retries = 0;
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function error() {
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if (self.retries > 2) {
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self.kill();
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process.exit();
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}
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self.retries++;
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}
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setInterval(() => {
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try {
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let result = self.send({action: 'ping'});
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if (!result) {
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return error();
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}
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self.retries = 0;
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} catch (e) {
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error();
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}
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}, 500);
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}
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interceptLogs() {
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const context = {};
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context.console = console;
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context.console.log = this._log.bind(this, 'log');
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context.console.warn = this._log.bind(this, 'warn');
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context.console.error = this._log.bind(this, 'error');
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context.console.info = this._log.bind(this, 'info');
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context.console.debug = this._log.bind(this, 'debug');
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context.console.trace = this._log.bind(this, 'trace');
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context.console.dir = this._log.bind(this, 'dir');
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}
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_log(type, ...messages) {
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const isHardSource = messages.some(message => {
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return (typeof message === 'string' && message.indexOf('hardsource') > -1);
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});
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if (isHardSource) {
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return;
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}
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this.send({result: constants.process.log, message: messages, type});
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}
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send() {
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if (!process.connected) {
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return false;
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}
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return process.send(...arguments);
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}
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kill() {
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// Should be implemented by derived class
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console.log('Process killed');
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}
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}
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process.on('exit', () => {
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process.exit(0);
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});
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module.exports = ProcessWrapper;
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