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.

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