Promise Profiler

This repo will profile your code by giving the execution time of all promises in a json without disturbing the production level code.

Documentation

• The documentation can be found here.

Installation

• Install bluebird-promise-profiler as dev dependency

   npm i --save-dev bluebird-promise-profiler
  

• Please upgrade to the latest version for bug free experience.

• Version >= 1.3.0 of this package works for all node versions.

Usage

• We will implement routes and model for two function multiply and square (the working examples can be seen in ./examples of this repository).

• File: ./routes/route.js

   'use strict';
   
   const Promise = require('bluebird');
   const Model = require('../models/Model');
   
   /**
    * Route for calling square function in ../models/Model.js
    * @param num
    * @returns {Promise}
    */
   const squareRoute = function squareRoute (num) {
   
   	return Model.square(num)
   		// the function name 'squarePromise' will be one of the key in output of the profiler whose value would be around 1000 milliseconds
   		.then(function squarePromise (result) {
   
   			return {result};
   
   		});
   };
   
   const squareAndMultiplyRoute = function squareAndMultiply (num1, num2) {
   
   	return Promise.join(Model.multiply(num1, num2), Model.square(num1))
   		// the function name 'spreadFunction' will be one of the key in output of the profiler whose value would be around 2000 milliseconds
   		.spread(function spreadFunction (multiplyResult, squareResult) {
   			return {multiplyResult, squareResult};
   		});
   
   };
   
   module.exports = {
   	squareRoute: squareRoute,
   	squareAndMultiplyRoute: squareAndMultiplyRoute
   };
   

• File: ./models/Model.js

   'use strict';
   
   const Promise = require('bluebird');
   
   /**
    * Makes a delay of one second and returns back a promise which multiplies the two numbers.
    * @param num1
    * @param num2
    * @returns {bluebird} Returns back a promise which multiplies the two numbers.
    */
   const multiply = function multiply (num1, num2) {
   
   	return new Promise (function (resolve, reject) {
   
   		setTimeout(function promise1Timeout () {
   			resolve(num1 * num2);
   		}, 1000);
   
   	});
   
   };
   
   /**
    * Makes delay of one second and then calls multiply which further makes a delay of one second, so total delay is two seconds.
    * @param num1
    * @returns {bluebird} Returns back a promise which multiplies the given number.
    */
   const square = function square (num1) {
   
   	return new Promise (function (resolve, reject) {
   
   		setTimeout(function promise1Timeout () {
   
   			multiply(num1, num1)
   				// the function name 'multiplyPromise' will be one of the key in output of the profiler whose value would be around 1000 milliseconds
   				.then(function multiplyPromise (result) {
   					resolve(result);
   				});
   
   		}, 1000);
   
   	});
   
   };
   
   module.exports = {
   	square: square,
   	multiply: multiply
   };
   

• The above are the files for routes and model respectively for squaring and multiplying numbers.

• The multiply function in models causes a delay of one second and returns the output, therefore total time taken by square function is one seconds

• The square function also makes a delay of one second and then calls the multiply function, therefore total time taken by square function is two seconds.

• So now we need to profile this, without touching the code, now we make a temporary file called profiler.js

• profiler.js

   'use strict';
   // to run this file type 'node profiler' in the terminal
  
   const route = require('./routes/route');
   
   const promiseProfiler = require('bluebird-promise-profiler');
   promiseProfiler.startProfiling();
   
   //call square route
   route.squareRoute(5).then((res) => {
   
   	// { result: 25 }
   	console.log(res);
   
   	// { multiplyPromise: 1004.3564850000002, squarePromise: 2009.1301549999998 }
   	console.log(promiseProfiler.getProfilerResult());
   
   	// reset profiler result to analyze other route
   	promiseProfiler.resetProfiler();
   
   	// call squareAndMultiply route
   	route.squareAndMultiplyRoute(4, 5).then((result) => {
   
   		// { multiplyResult: 20, squareResult: 16 }
   		console.log(result);
   
   		// note there is a multiplyPromise included in this response as square function internally calls multiply function
   		// { multiplyPromise: 1004.7086040000004, spreadFunction: 2008.4984540000005 }
   		console.log(promiseProfiler.getProfilerResult());
   
   		// stop the profiler once the profiling is done
   		promiseProfiler.stopProfiling();
   	});
   
   });
   

• Profiling would be done according to the function names given in .then() and .spread() functions.

• Anonymous functions given inside .then() or .spread() will not be profiled. So please do give names into those functions.

Examples

• Steps to run examples in this repo:

   npm run-script examples
  

Tests

• Test without code coverage

   npm test
  

• Test with code coverage

   npm run-script test-with-coverage