Simple Chat Room in NodeJS, expressJS and mongoDB in Docker Swarm
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let EventEmitter = require('events').EventEmitter;
let async = require('async');
let chalk = require('chalk');
// 'rule' module is required at the bottom because circular deps
// Used for task value, so better not to use
// null, since value should be unset/uninitialized
let UNDEFINED_VALUE;
const ROOT_TASK_NAME = '__rootTask__';
const POLLING_INTERVAL = 100;
// Parse any positional args attached to the task-name
function parsePrereqName(name) {
let taskArr = name.split('[');
let taskName = taskArr[0];
let taskArgs = [];
if (taskArr[1]) {
taskArgs = taskArr[1].replace(/\]$/, '');
taskArgs = taskArgs.split(',');
}
return {
name: taskName,
args: taskArgs
};
}
/**
@name jake.Task
@class
@extends EventEmitter
@description A Jake Task
@param {String} name The name of the Task
@param {Array} [prereqs] Prerequisites to be run before this task
@param {Function} [action] The action to perform for this task
@param {Object} [opts]
@param {Array} [opts.asyc=false] Perform this task asynchronously.
If you flag a task with this option, you must call the global
`complete` method inside the task's action, for execution to proceed
to the next task.
*/
class Task extends EventEmitter {
constructor(name, prereqs, action, options) {
// EventEmitter ctor takes no args
super();
if (name.indexOf(':') > -1) {
throw new Error('Task name cannot include a colon. It is used internally as namespace delimiter.');
}
let opts = options || {};
this._currentPrereqIndex = 0;
this._internal = false;
this._skipped = false;
this.name = name;
this.prereqs = prereqs;
this.action = action;
this.async = false;
this.taskStatus = Task.runStatuses.UNSTARTED;
this.description = null;
this.args = [];
this.value = UNDEFINED_VALUE;
this.concurrency = 1;
this.startTime = null;
this.endTime = null;
this.directory = null;
this.namespace = null;
// Support legacy async-flag -- if not explicitly passed or falsy, will
// be set to empty-object
if (typeof opts == 'boolean' && opts === true) {
this.async = true;
}
else {
if (opts.async) {
this.async = true;
}
if (opts.concurrency) {
this.concurrency = opts.concurrency;
}
}
//Do a test on self dependencies for this task
if(Array.isArray(this.prereqs) && this.prereqs.indexOf(this.name) !== -1) {
throw new Error("Cannot use prereq " + this.name + " as a dependency of itself");
}
}
get fullName() {
return this._getFullName();
}
_initInvocationChain() {
// Legacy global invocation chain
jake._invocationChain.push(this);
// New root chain
if (!this._invocationChain) {
this._invocationChainRoot = true;
this._invocationChain = [];
if (jake.currentRunningTask) {
jake.currentRunningTask._waitForChains = jake.currentRunningTask._waitForChains || [];
jake.currentRunningTask._waitForChains.push(this._invocationChain);
}
}
}
/**
@name jake.Task#invoke
@function
@description Runs prerequisites, then this task. If the task has already
been run, will not run the task again.
*/
invoke() {
this._initInvocationChain();
this.args = Array.prototype.slice.call(arguments);
this.reenabled = false
this.runPrereqs();
}
/**
@name jake.Task#execute
@function
@description Run only this task, without prereqs. If the task has already
been run, *will* run the task again.
*/
execute() {
this._initInvocationChain();
this.args = Array.prototype.slice.call(arguments);
this.reenable();
this.reenabled = true
this.run();
}
runPrereqs() {
if (this.prereqs && this.prereqs.length) {
if (this.concurrency > 1) {
async.eachLimit(this.prereqs, this.concurrency,
(name, cb) => {
let parsed = parsePrereqName(name);
let prereq = this.namespace.resolveTask(parsed.name) ||
jake.attemptRule(name, this.namespace, 0) ||
jake.createPlaceholderFileTask(name, this.namespace);
if (!prereq) {
throw new Error('Unknown task "' + name + '"');
}
//Test for circular invocation
if(prereq === this) {
setImmediate(function () {
cb(new Error("Cannot use prereq " + prereq.name + " as a dependency of itself"));
});
}
if (prereq.taskStatus == Task.runStatuses.DONE) {
//prereq already done, return
setImmediate(cb);
}
else {
//wait for complete before calling cb
prereq.once('_done', () => {
prereq.removeAllListeners('_done');
setImmediate(cb);
});
// Start the prereq if we are the first to encounter it
if (prereq.taskStatus === Task.runStatuses.UNSTARTED) {
prereq.taskStatus = Task.runStatuses.STARTED;
prereq.invoke.apply(prereq, parsed.args);
}
}
},
(err) => {
//async callback is called after all prereqs have run.
if (err) {
throw err;
}
else {
setImmediate(this.run.bind(this));
}
}
);
}
else {
setImmediate(this.nextPrereq.bind(this));
}
}
else {
setImmediate(this.run.bind(this));
}
}
nextPrereq() {
let self = this;
let index = this._currentPrereqIndex;
let name = this.prereqs[index];
let prereq;
let parsed;
if (name) {
parsed = parsePrereqName(name);
prereq = this.namespace.resolveTask(parsed.name) ||
jake.attemptRule(name, this.namespace, 0) ||
jake.createPlaceholderFileTask(name, this.namespace);
if (!prereq) {
throw new Error('Unknown task "' + name + '"');
}
// Do when done
if (prereq.taskStatus == Task.runStatuses.DONE) {
self.handlePrereqDone(prereq);
}
else {
prereq.once('_done', () => {
this.handlePrereqDone(prereq);
prereq.removeAllListeners('_done');
});
if (prereq.taskStatus == Task.runStatuses.UNSTARTED) {
prereq.taskStatus = Task.runStatuses.STARTED;
prereq._invocationChain = this._invocationChain;
prereq.invoke.apply(prereq, parsed.args);
}
}
}
}
/**
@name jake.Task#reenable
@function
@description Reenables a task so that it can be run again.
*/
reenable(deep) {
let prereqs;
let prereq;
this._skipped = false;
this.taskStatus = Task.runStatuses.UNSTARTED;
this.value = UNDEFINED_VALUE;
if (deep && this.prereqs) {
prereqs = this.prereqs;
for (let i = 0, ii = prereqs.length; i < ii; i++) {
prereq = jake.Task[prereqs[i]];
if (prereq) {
prereq.reenable(deep);
}
}
}
}
handlePrereqDone(prereq) {
this._currentPrereqIndex++;
if (this._currentPrereqIndex < this.prereqs.length) {
setImmediate(this.nextPrereq.bind(this));
}
else {
setImmediate(this.run.bind(this));
}
}
isNeeded() {
let needed = true;
if (this.taskStatus == Task.runStatuses.DONE) {
needed = false;
}
return needed;
}
run() {
let val, previous;
let hasAction = typeof this.action == 'function';
if (!this.isNeeded()) {
this.emit('skip');
this.emit('_done');
}
else {
if (this._invocationChain.length) {
previous = this._invocationChain[this._invocationChain.length - 1];
// If this task is repeating and its previous is equal to this, don't check its status because it was set to UNSTARTED by the reenable() method
if (!(this.reenabled && previous == this)) {
if (previous.taskStatus != Task.runStatuses.DONE) {
let now = (new Date()).getTime();
if (now - this.startTime > jake._taskTimeout) {
return jake.fail(`Timed out waiting for task: ${previous.name} with status of ${previous.taskStatus}`);
}
setTimeout(this.run.bind(this), POLLING_INTERVAL);
return;
}
}
}
if (!(this.reenabled && previous == this)) {
this._invocationChain.push(this);
}
if (!(this._internal || jake.program.opts.quiet)) {
console.log("Starting '" + chalk.green(this.fullName) + "'...");
}
this.startTime = (new Date()).getTime();
this.emit('start');
jake.currentRunningTask = this;
if (hasAction) {
try {
if (this.directory) {
process.chdir(this.directory);
}
val = this.action.apply(this, this.args);
if (typeof val == 'object' && typeof val.then == 'function') {
this.async = true;
val.then(
(result) => {
setImmediate(() => {
this.complete(result);
});
},
(err) => {
setImmediate(() => {
this.errorOut(err);
});
});
}
}
catch (err) {
this.errorOut(err);
return; // Bail out, not complete
}
}
if (!(hasAction && this.async)) {
setImmediate(() => {
this.complete(val);
});
}
}
}
errorOut(err) {
this.taskStatus = Task.runStatuses.ERROR;
this._invocationChain.chainStatus = Task.runStatuses.ERROR;
this.emit('error', err);
}
complete(val) {
if (Array.isArray(this._waitForChains)) {
let stillWaiting = this._waitForChains.some((chain) => {
return !(chain.chainStatus == Task.runStatuses.DONE ||
chain.chainStatus == Task.runStatuses.ERROR);
});
if (stillWaiting) {
let now = (new Date()).getTime();
let elapsed = now - this.startTime;
if (elapsed > jake._taskTimeout) {
return jake.fail(`Timed out waiting for task: ${this.name} with status of ${this.taskStatus}. Elapsed: ${elapsed}`);
}
setTimeout(() => {
this.complete(val);
}, POLLING_INTERVAL);
return;
}
}
jake._invocationChain.splice(jake._invocationChain.indexOf(this), 1);
if (this._invocationChainRoot) {
this._invocationChain.chainStatus = Task.runStatuses.DONE;
}
this._currentPrereqIndex = 0;
// If 'complete' getting called because task has been
// run already, value will not be passed -- leave in place
if (!this._skipped) {
this.taskStatus = Task.runStatuses.DONE;
this.value = val;
this.emit('complete', this.value);
this.emit('_done');
this.endTime = (new Date()).getTime();
let taskTime = this.endTime - this.startTime;
if (!(this._internal || jake.program.opts.quiet)) {
console.log("Finished '" + chalk.green(this.fullName) + "' after " + chalk.magenta(taskTime + ' ms'));
}
}
}
_getFullName() {
let ns = this.namespace;
let path = (ns && ns.path) || '';
path = (path && path.split(':')) || [];
if (this.namespace !== jake.defaultNamespace) {
path.push(this.namespace.name);
}
path.push(this.name);
return path.join(':');
}
static getBaseNamespacePath(fullName) {
return fullName.split(':').slice(0, -1).join(':');
}
static getBaseTaskName(fullName) {
return fullName.split(':').pop();
}
}
Task.runStatuses = {
UNSTARTED: 'unstarted',
DONE: 'done',
STARTED: 'started',
ERROR: 'error'
};
Task.ROOT_TASK_NAME = ROOT_TASK_NAME;
exports.Task = Task;
// Required here because circular deps
require('../rule');