Nodemon crashed when bound with gulp watch and restarted more than twice - node.js

I am trying to make my processes (webpack, nodemon-restart) work with a single gulp command. This works well enough. However, webpack builds only once if its task is tied to gulp's default task (together with nodemon), or embedded withing nodemon's gulp task.
Then I decided to tie both webpack build task and nodemon restart task to gulp's watch command and this works just the way I wanted, except that if you make changes and save them more than twice, the app nodemon crashed and prints this error in the console
"/home/nnanyielugo/Workspace/activity-calendar/node_modules/nodemon/lib/monitor/match.js:132
var rules = monitor.sort(function (a, b) {
^
TypeError: Cannot read property 'sort' of undefined"
As a solution, i tried to tie the webpack build task to the nodemon restart using the .on() method, and instead got an infinite loop of restarting an rebuilding (nodemon restarts first, webpack builds, nodemon restarts again, webpack rebuilds, and on and on).
Does anyone have a solution please?`
Here is a sample of my code `
var gulp = require('gulp'),
nodemon = require('gulp-nodemon'),
webpack = require('webpack-stream');
gulp.task('default', ['watch']);
gulp.task('webpack', function() {
return gulp.src('src/entry.js')
.pipe(webpack(require('./webpack.config.js')))
.pipe(gulp.dest('./public'));
});
gulp.task('nodemon', function () {
return nodemon({
script: 'app.js'
, ext: 'js html'
, env: { 'NODE_ENV': 'development' }
})
})
gulp.task('watch', function(){
gulp.watch(['./api/**/*.js', './server/**/*.js', './*.js'], ['webpack', 'nodemon']);
})`

I guess, your nodemon and gulp's watch task collides with each other. Either you should get ride of using nodemon and to rely upon gulp to start your application.
Or else, you can get rid of your gulp's watch task and add the relevant script in your nodemon's restart method like this,
nodemon({
// script goes here.
}).on('restart', your_reload_logic)
Hope this helps!

Related

Gulp task isn't running properly when called manually?

I have a gulp task that contains this task:
gulp.task("js", function() {
console.log('Gulp task JS run')
gulp.src('scripts/*.js')
.pipe(sourcemaps.init())
.pipe(include())
.on('error', console.log)
.pipe(sourcemaps.write('./maps'))
.pipe(gulp.dest("public/javascripts"));
});
I try to run the task from node like this:
var gulp = require('gulp');
require('../../gulpfile');
if (gulp.tasks.js) {
console.log('gulpfile contains task!');
gulp.start('js');
}
And I see "gulpfile contains task" and "Gulp task JS run" in the console, but the it it doesn't seem to actually run, the files are not updated. When running it manually from bash with "gulp js" or from the watch task, it works fine.
Is there any reason this would happen or any way I can troubleshoot it further?

Gulp Watching Creates Infinite Loop Without Changing Files

Similar to other questions, in this very watered-down snippet, running the default gulp task (via npm start which runs gulp); this snippet creates an infinite loop running the scripts task over and over. Here is the gulpfile.js (literally the whole thing at the moment):
'use strict';
const gulp = require('gulp');
// COPY SCRIPTS TO BUILD FOLDER
gulp.task('scripts', function() {
return gulp.src('./scripts/**/*.js')
.pipe(gulp.dest('build/scripts'))
});
// WATCH FILES
gulp.task('watch', function() {
gulp.watch('./scripts/**/*.js', ['scripts']);
});
// DEFAULT
gulp.task('default', ['watch']);
The extra odd thing is that whether the build folder is built anew or not, the scripts task will be executed immediately after calling npm start! And the loop begins.
In case you're curious, here is the pasted (and only) scripts object in my package.json:
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1",
"start": "gulp"
},
The only other thing in my directory is a scripts folder with an app.js and an home.js file in it. Obviously once this task is run, the build folder is created (if it wasn't already there yet) and the two aforementioned files are copied into it.
You can see I'm only looking for scripts in the root directory's first level folder called scripts, so I shouldn't have an infinite loop by referencing changes on the same set of scripts. Also, even if I'm explicit, and point to exactly one particular file with a relative path such as ./scripts/home.js this still happens.
I'm anticipating being embarrassed, but I'm utterly confused.
A few things I've picked up on which could be causing some errors.
EDIT -
Try the watch plugin npm install --save-dev gulp-watch
// Try and declare your plugins like this for now.
var gulp = require('gulp'),
watch = require('gulp-watch');
// Provide a callback, cb
gulp.task('scripts', function(cb) {
// Dont use ./ on your src as watch can have a problem with this
return gulp.src('scripts/**/*.js')
.pipe(gulp.dest('./build/scripts'), cb); // call cb and dont forget ;
});
// remove ./ on watch
gulp.task('watch', function() {
gulp.watch('scripts/**/*.js', ['scripts']);
});
gulp.task('default', ['watch']);
So that is pretty weird behaviour but this should do the trick.
The only time I use ./ within gulp is on my dest.
Also just remember that gulpfile is just a JS so remember your semicolon, etc.
I cannot guarantee the resolution here, but I had a two variables that changed when this was resolved:
I upgraded my Parallels VM application (on an Apple PowerBook) from
version 10 -> 11.
I reinstalled Windows 10 using another license for a current version
(the previous one was a licensed dev or early release version).
My code, Node version, devDependencies and versions were identical.

gulp-nodemon watcher does not work

i'm developing a websocket server, I tried to restart the server with nodemon as soon as i change it. However it appears that this is not working for me.
gulp.task('startWebsocketServer', function() {
return nodemon({
script: './server/websocket/server.js',
watch: ['./server/websocket/**/*.js']
});
});
Does anyone have an idea what i did wrong here?
nodemon is on version 1.9.2 and nodejs on 4.2.6.
gulp-nodemon inherits its options from nodemon. Concerning the watch option the docs say this:
By default nodemon will traverse sub-directories, so there's no need in explicitly including sub-directories. [...] Don't use unix globbing to pass multiple directories, e.g --watch ./lib/*, it won't work
So can't and don't need to use a globstar ** in your watch option. Simply specifying the directory should suffice:
gulp.task('startWebsocketServer', function() {
return nodemon({
script: './server/websocket/server.js',
watch: ['./server/websocket']
});
});

gulp with nodemon, watch for file changes, "app crashed - waiting for file changes before starting"

I'm trying to automate a simple gulp task to run/debug node, watch for file changes, and restart node if any files change. Most popular recipes I've seen for this use gulp-nodemon, but when a file change event occurs, (gulp-) nodemon crashes:
[nodemon] app crashed - waiting for file changes before starting...
The crashing happens inconsistently, so sometimes I have to manually send a SIGINT to stop the node process (which kind of defeats the purpose of nodemon).
I want to be able to run a gulp task that can watch files, run or debug node. How can this be accomplished without nodemon crashing?
It's not fancy, but the following should accomplish what you want.
'use strict'
const gulp = require('gulp');
const spawn = require('child_process').spawn;
gulp.task('debug', function() {
let child = spawn("node", ["debug", "./server.js"], { stdio: 'inherit' });
gulp.watch([__dirname + "/*.js", '!gulpfile.js'], function(event) {
console.log(`File %s was %s.`, event.path, event.type);
if (child) {
child.kill();
child = spawn("node", ["debug", "./server.js"], { stdio: 'inherit' });
}
});
});
This assumes you're watching for changes to any js files in __dirname except for your gulpfile.

Gulp + Webpack or JUST Webpack?

I see people using gulp with webpack. But then I read webpack can replace gulp? I'm completely confused here...can someone explain?
UPDATE
in the end I started with gulp. I was new to modern front-end and just wanted to get up and running quick. Now that I've got my feet quite wet after more than a year, I'm ready to move to webpack. I suggest the same route for people who start off in the same shoes. Not saying you can't try webpack but just sayin if it seems complicated start with gulp first...nothing wrong with that.
If you don't want gulp, yes there's grunt but you could also just specify commands in your package.json and call them from the command-line without a task runner just to get up and running initially. For example:
"scripts": {
"babel": "babel src -d build",
"browserify": "browserify build/client/app.js -o dist/client/scripts/app.bundle.js",
"build": "npm run clean && npm run babel && npm run prepare && npm run browserify",
"clean": "rm -rf build && rm -rf dist",
"copy:server": "cp build/server.js dist/server.js",
"copy:index": "cp src/client/index.html dist/client/index.html",
"copy": "npm run copy:server && npm run copy:index",
"prepare": "mkdir -p dist/client/scripts/ && npm run copy",
"start": "node dist/server"
},
This answer might help. Task Runners (Gulp, Grunt, etc) and Bundlers (Webpack, Browserify). Why use together?
...and here's an example of using webpack from within a gulp task. This goes a step further and assumes that your webpack config is written in es6.
var gulp = require('gulp');
var webpack = require('webpack');
var gutil = require('gutil');
var babel = require('babel/register');
var config = require(path.join('../..', 'webpack.config.es6.js'));
gulp.task('webpack-es6-test', function(done){
webpack(config).run(onBuild(done));
});
function onBuild(done) {
return function(err, stats) {
if (err) {
gutil.log('Error', err);
if (done) {
done();
}
} else {
Object.keys(stats.compilation.assets).forEach(function(key) {
gutil.log('Webpack: output ', gutil.colors.green(key));
});
gutil.log('Webpack: ', gutil.colors.blue('finished ', stats.compilation.name));
if (done) {
done();
}
}
}
}
I think you'll find that as your app gets more complicated, you might want to use gulp with a webpack task as per example above. This allows you to do a few more interesting things in your build that webpack loaders and plugins really don't do, ie. creating output directories, starting servers, etc. Well, to be succinct, webpack actually can do those things, but you might find them limited for your long term needs. One of the biggest advantages you get from gulp -> webpack is that you can customize your webpack config for different environments and have gulp do the right task for the right time. Its really up to you, but there's nothing wrong with running webpack from gulp, in fact there's some pretty interesting examples of how to do it. The example above is basically from jlongster.
NPM scripts can do the same as gulp, but in about 50x less code. In fact, with no code at all, only command line arguments.
For example, the use case you described where you want to have different code for different environments.
With Webpack + NPM Scripts, it's this easy:
"prebuild:dev": "npm run clean:wwwroot",
"build:dev": "cross-env NODE_ENV=development webpack --config config/webpack.development.js --hot --profile --progress --colors --display-cached",
"postbuild:dev": "npm run copy:index.html && npm run rename:index.html",
"prebuild:production": "npm run clean:wwwroot",
"build:production": "cross-env NODE_ENV=production webpack --config config/webpack.production.js --profile --progress --colors --display-cached --bail",
"postbuild:production": "npm run copy:index.html && npm run rename:index.html",
"clean:wwwroot": "rimraf -- wwwroot/*",
"copy:index.html": "ncp wwwroot/index.html Views/Shared",
"rename:index.html": "cd ../PowerShell && elevate.exe -c renamer --find \"index.html\" --replace \"_Layout.cshtml\" \"../MyProject/Views/Shared/*\"",
Now you simply maintain two webpack config scripts, one for development mode, webpack.development.js, and one for production mode, webpack.production.js. I also utilize a webpack.common.js which houses webpack config shared on all environments, and use webpackMerge to merge them.
Because of the coolness of NPM scripts, it allows for easy chaining, similar to how gulp does Streams/pipes.
In the example above, to build for developement, you simply go to your command line and execute npm run build:dev.
NPM would first run prebuild:dev,
Then build:dev,
And finally postbuild:dev.
The pre and post prefixes tell NPM which order to execute in.
If you notice, with Webpack + NPM scripts, you can run a native programs, such as rimraf, instead of a gulp-wrapper for a native program such as gulp-rimraf. You can also run native Windows .exe files as I did here with elevate.exe or native *nix files on Linux or Mac.
Try doing the same thing with gulp. You'll have to wait for someone to come along and write a gulp-wrapper for the native program you want to use. In addition, you'll likely need to write convoluted code like this: (taken straight from angular2-seed repo)
Gulp Development code
import * as gulp from 'gulp';
import * as gulpLoadPlugins from 'gulp-load-plugins';
import * as merge from 'merge-stream';
import * as util from 'gulp-util';
import { join/*, sep, relative*/ } from 'path';
import { APP_DEST, APP_SRC, /*PROJECT_ROOT, */TOOLS_DIR, TYPED_COMPILE_INTERVAL } from '../../config';
import { makeTsProject, templateLocals } from '../../utils';
const plugins = <any>gulpLoadPlugins();
let typedBuildCounter = TYPED_COMPILE_INTERVAL; // Always start with the typed build.
/**
* Executes the build process, transpiling the TypeScript files (except the spec and e2e-spec files) for the development
* environment.
*/
export = () => {
let tsProject: any;
let typings = gulp.src([
'typings/index.d.ts',
TOOLS_DIR + '/manual_typings/**/*.d.ts'
]);
let src = [
join(APP_SRC, '**/*.ts'),
'!' + join(APP_SRC, '**/*.spec.ts'),
'!' + join(APP_SRC, '**/*.e2e-spec.ts')
];
let projectFiles = gulp.src(src);
let result: any;
let isFullCompile = true;
// Only do a typed build every X builds, otherwise do a typeless build to speed things up
if (typedBuildCounter < TYPED_COMPILE_INTERVAL) {
isFullCompile = false;
tsProject = makeTsProject({isolatedModules: true});
projectFiles = projectFiles.pipe(plugins.cached());
util.log('Performing typeless TypeScript compile.');
} else {
tsProject = makeTsProject();
projectFiles = merge(typings, projectFiles);
}
result = projectFiles
.pipe(plugins.plumber())
.pipe(plugins.sourcemaps.init())
.pipe(plugins.typescript(tsProject))
.on('error', () => {
typedBuildCounter = TYPED_COMPILE_INTERVAL;
});
if (isFullCompile) {
typedBuildCounter = 0;
} else {
typedBuildCounter++;
}
return result.js
.pipe(plugins.sourcemaps.write())
// Use for debugging with Webstorm/IntelliJ
// https://github.com/mgechev/angular2-seed/issues/1220
// .pipe(plugins.sourcemaps.write('.', {
// includeContent: false,
// sourceRoot: (file: any) =>
// relative(file.path, PROJECT_ROOT + '/' + APP_SRC).replace(sep, '/') + '/' + APP_SRC
// }))
.pipe(plugins.template(templateLocals()))
.pipe(gulp.dest(APP_DEST));
};
Gulp Production code
import * as gulp from 'gulp';
import * as gulpLoadPlugins from 'gulp-load-plugins';
import { join } from 'path';
import { TMP_DIR, TOOLS_DIR } from '../../config';
import { makeTsProject, templateLocals } from '../../utils';
const plugins = <any>gulpLoadPlugins();
const INLINE_OPTIONS = {
base: TMP_DIR,
useRelativePaths: true,
removeLineBreaks: true
};
/**
* Executes the build process, transpiling the TypeScript files for the production environment.
*/
export = () => {
let tsProject = makeTsProject();
let src = [
'typings/index.d.ts',
TOOLS_DIR + '/manual_typings/**/*.d.ts',
join(TMP_DIR, '**/*.ts')
];
let result = gulp.src(src)
.pipe(plugins.plumber())
.pipe(plugins.inlineNg2Template(INLINE_OPTIONS))
.pipe(plugins.typescript(tsProject))
.once('error', function () {
this.once('finish', () => process.exit(1));
});
return result.js
.pipe(plugins.template(templateLocals()))
.pipe(gulp.dest(TMP_DIR));
};
The actual gulp code is much more complicated that this, as this is only 2 of the several dozen gulp files in the repo.
So, which one is easier to you?
In my opinion, NPM scripts far surpasses gulp and grunt, in both effectiveness and ease of use, and all front-end developers should consider using it in their workflow because it is a major time saver.
UPDATE
There is one scenario I've encountered where I wanted to use Gulp in combination with NPM scripts and Webpack.
When I need to do remote debugging on an iPad or Android device for example, I need to start up extra servers. In the past I ran all the servers as separate processes, from within IntelliJ IDEA (Or Webstorm) that is easy with the "Compound" Run Configuration. But if I need to stop and restart them, it was tedious to have to close 5 different server tabs, plus the output was spread across the different windows.
One of the benefits of gulp is that is can chain all the output from separate independent processes into one console window, which becomes the parent of all the child servers.
So I created a very simple gulp task that just runs my NPM scripts or the commands directly, so all the output appears in one window, and I can easily end all 5 servers at once by closing the gulp task window.
Gulp.js
/**
* Gulp / Node utilities
*/
var gulp = require('gulp-help')(require('gulp'));
var utils = require('gulp-util');
var log = utils.log;
var con = utils.colors;
/**
* Basic workflow plugins
*/
var shell = require('gulp-shell'); // run command line from shell
var browserSync = require('browser-sync');
/**
* Performance testing plugins
*/
var ngrok = require('ngrok');
// Variables
var serverToProxy1 = "localhost:5000";
var finalPort1 = 8000;
// When the user enters "gulp" on the command line, the default task will automatically be called. This default task below, will run all other tasks automatically.
// Default task
gulp.task('default', function (cb) {
console.log('Starting dev servers!...');
gulp.start(
'devserver:jit',
'nodemon',
'browsersync',
'ios_webkit_debug_proxy'
'ngrok-url',
// 'vorlon',
// 'remotedebug_ios_webkit_adapter'
);
});
gulp.task('nodemon', shell.task('cd ../backend-nodejs && npm run nodemon'));
gulp.task('devserver:jit', shell.task('npm run devserver:jit'));
gulp.task('ios_webkit_debug_proxy', shell.task('npm run ios-webkit-debug-proxy'));
gulp.task('browsersync', shell.task(`browser-sync start --proxy ${serverToProxy1} --port ${finalPort1} --no-open`));
gulp.task('ngrok-url', function (cb) {
return ngrok.connect(finalPort1, function (err, url) {
site = url;
log(con.cyan('ngrok'), '- serving your site from', con.yellow(site));
cb();
});
});
// gulp.task('vorlon', shell.task('vorlon'));
// gulp.task('remotedebug_ios_webkit_adapter', shell.task('remotedebug_ios_webkit_adapter'));
Still quite a bit of code just to run 5 tasks, in my opinion, but it works for the purpose. One caveate is that gulp-shell doesn't seem to run some commands correctly, such as ios-webkit-debug-proxy. So I had to create an NPM Script that just executes the same command, and then it works.
So I primarily use NPM Scripts for all my tasks, but occasionally when I need to run a bunch of servers at once, I'll fire up my Gulp task to help out. Pick the right tool for the right job.
UPDATE 2
I now use a script called concurrently which does the same thing as the gulp task above. It runs multiple CLI scripts in parallel and pipes them all to the same console window, and its very simple to use. Once again, no code required (well, the code is inside the node_module for concurrently, but you don't have to concern yourself with that)
// NOTE: If you need to run a command with spaces in it, you need to use
// double quotes, and they must be escaped (at least on windows).
// It doesn't seem to work with single quotes.
"run:all": "concurrently \"npm run devserver\" nodemon browsersync ios_webkit_debug_proxy ngrok-url"
This runs all 5 scripts in parallel piped out to one terminal. Awesome! So that this point, I rarely use gulp, since there are so many cli scripts to do the same tasks with no code.
I suggest you read these articles which compare them in depth.
How to Use NPM as a Build Tool
Why we should stop using Grunt & Gulp
Why I Left Gulp and Grunt for NPM Scripts
I used both options in my different projects.
Here is one boilerplate that I put together using gulp with webpack - https://github.com/iroy2000/react-reflux-boilerplate-with-webpack.
I have some other project used only webpack with npm tasks.
And they both works totally fine. And I think it burns down to is how complicated your task is, and how much control you want to have in your configuration.
For example, if you tasks is simple, let's say dev, build, test ... etc ( which is very standard ), you are totally fine with just simple webpack with npm tasks.
But if you have very complicated workflow and you want to have more control of your configuration ( because it is coding ), you could go for gulp route.
But from my experience, webpack ecosystem provides more than enough plugins and loaders that I will need, and so I love using the bare minimum approach unless there is something you can only do in gulp. And also, it will make your configuration easier if you have one less thing in your system.
And a lot of times, nowadays, I see people actually replacing gulp and browsify all together with webpack alone.
The concepts of Gulp and Webpack are quite different. You tell Gulp how to put front-end code together step-by-step, but you tell Webpack what you want through a config file.
Here is a short article (5 min read) I wrote explaining my understanding of the differences: https://medium.com/#Maokai/compile-the-front-end-from-gulp-to-webpack-c45671ad87fe
Our company moved from Gulp to Webpack in the past year. Although it took some time, we figured out how to move all we did in Gulp to Webpack. So to us, everything we did in Gulp we can also do through Webpack, but not the other way around.
As of today, I'd suggest just use Webpack and avoid the mixture of Gulp and Webpack so you and your team do not need to learn and maintain both, especially because they are requiring very different mindsets.
Honestly I think the best is to use both.
Webpack for all javascript related.
Gulp for all css related.
I still have to find a decent solution for packaging css with webpack, and so far I am happy using gulp for css and webpack for javascript.
I also use npm scripts as #Tetradev as described. Especially since I am using Visual Studio, and while NPM Task runner is pretty reliable Webpack Task Runner is pretty buggy.

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