usher

<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <title>JSDoc: Source: decider/tasks/accumulator.js</title> <script src="scripts/prettify/prettify.js"> </script> <script src="scripts/prettify/lang-css.js"> </script>  <link type="text/css" rel="stylesheet" href="styles/prettify-tomorrow.css"> <link type="text/css" rel="stylesheet" href="styles/jsdoc-default.css"> </head> <body> <div id="main"> <h1 class="page-title">Source: decider/tasks/accumulator.js</h1> <section> <article> <pre class="prettyprint source linenums"><code>/*! * Usher * Copyright(c) 2016 meltmedia <mike@meltmedia.com> */ 'use strict'; var util = require('util'), winston = require('winston'), _ = require('lodash'), async = require('async'), WorkflowExecution = require('../execution'), Context = require('../context'), Task = require('./task'), STATUS = require('./status'); module.exports = Accumulator; /** * The Accumulator loop executes the `fragment` until the `resultsFn` returns an empty array, * the results of each execution are then pushed into an array via the `resultsFn` for use by other tasks. * * @constructor */ function Accumulator(name, deps, fragment, resultsFn, options) { if (!(this instanceof Accumulator)) { return new Accumulator(name, deps, fragment, resultsFn, options); } Task.apply(this, Array.prototype.slice.call(arguments)); this.fragment = fragment; if (!_.isFunction(resultsFn)) { throw new Error('You must provide a function to indicate when the accumulator is complete'); } this.resultsFn = resultsFn; this.options = options || {}; } util.inherits(Accumulator, Task); Accumulator.prototype.execute = function execute(ctx, done) { var resolvedName = ctx.namespace ? ctx.namespace + '-' + this.name : this.name, input = ctx.input(this), state = ctx.lastState(this), self = this, executionContexts; // Make sure we have a state state = state ? state : { currentIndex: 0 }; function evaluateState() { executionContexts = []; for (var i = 0; i <= state.currentIndex; i++) { // Build the execution context for the current iteration // Depending on the index, this could be the first of our iterations, or // picking back up a previously run iteration var currentExecution = { execution: new WorkflowExecution(self.fragment.sequencedTasks()), context: new Context(ctx.decisionTask, self.name + '-' + i, ctx.localVariables) }; executionContexts.push(currentExecution); } // Execute every iteration we've scheduled so far to see what state they are in // Does this need to be .mapSeries? async.reduce(executionContexts, [], function (memo, item, next) { // Store the previous result for use by later iterations input._variables.previousResult = _.get(_.last(memo), 'results', null); item.context.setWorkflowInput(input); item.execution.execute(item.context, function (err) { if (err) { return next(err); } if (item.context.failed()) { return next(new Error()); } // If current execution has finished running, check to see if it resolves our 'done' state if (item.context.done()) { // Get the results of this iteration var results = self.resultsFn.call(self, item.context.results); // We are done, we can mark our task resolved if (!_.isArray(results) || results.length < 1) { memo.push({ outstanding: false, done: true, results: results }); return next(null, memo); // The results of this execution did resolve the accumulators 'done' state } else { memo.push({ outstanding: false, done: false, results: results }); return next(null, memo); // The results of this execution did NOT resolve the accumulators 'done' state } } // This execution is still outstanding memo.push({ outstanding: true, done: false, results: [] }); return next(null, memo); }); // Once the states of our current iterations are complete, we evaluate the state of our task. // From here we can still be outstanding (waiting for task to finish), resolved (all work is done), or // schedule new tasks. }, function (err, results) { if (err) { winston.log('error', 'An problem occured in the accumulator: %s, failing due to: ', resolvedName, err.stack); return done(STATUS.mask('failed')); } var isOutstanding = _.some(results, 'outstanding'), isDone = _.some(results, 'done'); if (isOutstanding && isDone) { // This should never be true, if so, we need to let someone know winston.log('error', 'Invalid state in accumulator: %s, both \'done\' and \'outstanding\' state are currently true.', resolvedName); } // Still more work to be done on existing iterations if (isOutstanding) { return done(STATUS.mask('outstanding')); } // All iterations are complete and our 'done' criteria has been meet if (isDone) { // Make sure the results are available as a single array ctx.addResult(self, _.reduce(results, function (result, item) { return result.concat(item.results); }, [])); return done(STATUS.mask('complete', 'resolved')); } // Not done yet, schedule another iteration state.currentIndex++; // Save our state ctx.saveState(self, state); // Our input can change based on our current state input = ctx.input(self); // Evaluate the newly scheduled iteration evaluateState(); }); } // Run through the current state of the accumulator and set our state and schedule any work that needs to be done evaluateState(); }; </code></pre> </article> </section> </div> <nav> <h2><a href="index.html">Index</a></h2><h3>Classes</h3><ul><li><a href="Accumulator.html">Accumulator</a></li><li><a href="ActivityPoller.html">ActivityPoller</a></li><li><a href="ActivityTask.html">ActivityTask</a></li><li><a href="DecisionPoller.html">DecisionPoller</a></li><li><a href="Fragment.html">Fragment</a></li><li><a href="Loop.html">Loop</a></li><li><a href="Usher.html">Usher</a></li><li><a href="WhileLoop.html">WhileLoop</a></li><li><a href="WorkflowVersion.html">WorkflowVersion</a></li></ul> </nav> <br clear="both"> <footer> Documentation generated by <a href="https://github.com/jsdoc3/jsdoc">JSDoc 3.3.0-alpha5</a> on Mon Sep 12 2016 14:59:00 GMT-0700 (MST) </footer> <script> prettyPrint(); </script> <script src="scripts/linenumber.js"> </script> </body> </html>