How to use in node properties for deployment and local usage - javascript

I've created node application which I can run locally and in the cloud
Now I want that it be done somehow smoother and cleaner ,so I try to put some property in config.json file to check if I want to deploy the app or use it locally but I need to update manually this property before I change the propose , there is a better way to do it with node ?
let runnerServer = `http://localhost:8060/service/runner/${server.address().port}`;
if (cfg.isHosted) {
blogServer = `http://${serverName}/service/runner/${server.address().port}`;
}
and in the conig.json I've the field isHosted which I change manually(true/false) if I want to deploy or not...
update
maybe I can use process.env.PORT but this is just one example that I need to use in my code , currently I've several of fork that need to konw if Im in deployment or running locally ..

One option is to use use node's in built object called process.env (https://nodejs.org/api/process.html) and use two config files per se. This approach is somewhat similar to what you are doing but may be cleaner
config.localhost.json
config.production.json
then by setting properties on this object based on environment such as process.env.NODE_ENV = 'localhost' or process.env.NODE_ENV = 'production', you could read the corresponding file to import the configurations.
var config = require('./config.production.json');
if(process.env.NODE_ENV === 'localhost')
{
config = require('./config.localhost.json');
}
So to set this environment variable when running locally on your dev box , if
OSX - then on terminal export NODE_ENV=localhost
WINDOWS - then on cmd line set NODE_ENV=localhost

An easy way to solve this, if every environment configuration can be in the repo:
config.json:
production: {
// prod config
},
staging: {
// staging config
},
devel: {
// devel config
}
config.js:
const environment = process.env['ENV'] || 'devel';
module.exports = require('./config.json')[environment];
then in your package.json you could add the following scripts:
package.json
// npm stuff
scripts {
prod: "ENV=production node index.js",
stage: "ENV=staging node index.js",
dev: "ENV=devel node index.js"
}
and with this setup, you can run each configuration with the following commands:
production: npm run prod
staging: npm run stage
devel: npm run dev

Related

Change .page URL based on environment I need to run the suite in

We have been building our automation suite using our staging environment, but are going live soon and want to be ready to tell the project where to run (staging, production).
The only difference between the sites in the environments is the URL. My question is, from start to finish, how can I set the .page URL via a CLI option?
Right now, I have created an environment config file that holds our staging and production URLS and then I call the data into my test files. This is fine for now, but I will need to create a script with an option to set the environment at runtime without having to do a manual find and replace before kicking it off.
I've looked around online and find, what I believe, to be code snippets and general instructions, but I'm not a dev at heart and go crossed eyed. If I could get an ELI5 for this, that would be awesome.
Example of what I'm doing now:
const env = require('../environment_variables.json')
fixture `blog`
.page `${env.production}`
And then I change production to staging or vice versa manually before kicking off the suite.
Since the project will run from CICD, I would like to be able to do something like this in my CLI and script:
testcafe env=production
The env value will then be set where the .page call is for every test file.
Thanks!
There are different ways of doing this. I've used environment variables successfully in this situation, so I'll share this solution since it will solve your problem.
I create config.json in the root of the project:
{
"baseUrl": {
"dev": "https://dev.com/",
"staging": "https://staging.com/",
"prod": "https://prod.com/"
}
}
Then I create two helper functions somewhere like Helpers/env.js:
import config from '../config';
function getEnv () {
return process.env.TESTCAFE_ENV;
}
function getBaseUrl () {
return config.baseUrl[getEnv()];
}
export { getEnv, getBaseUrl };
Then in my test files in Tests/:
import { getBaseUrl } from '../Helpers/env';
const baseUrl = getBaseUrl();
fixture `Test Suite`
.page(baseUrl);
And that's it. Then when I need to run tests on the dev, I execute:
$ TESTCAFE_ENV=dev testcafe
for staging:
$ TESTCAFE_ENV=staging testcafe
and for production:
$ TESTCAFE_ENV=prod testcafe
In v1.20.0 and later, TestCafe offers a way to specify the baseUrl in the test run configuration. You can use this approach along with environment variables, see the following example:
.testcaferc.js
const BASE_URL_MAP = {
dev: 'https://dev.com/',
staging: 'https://staging.com/',
prod: 'https://prod.com/'
};
module.exports = {
baseUrl: BASE_URL_MAP[process.env.TESTCAFE_ENV]
};
Alternatively, you can use different configuration files for each of the required setups using the --config-file option.

Load a variable from dotenv file when starting PM2

I am starting instances of my app as a package.json script with PM2 this way:
"start:pm2": "pm2 start -i max node myapp.js"
I found out that not all members in the team always want to use max as a value for instances number while developing, but prefer to use some lower value.
To not change package.json I would better let them change the value inside .env file because we already use it so that the value from it would be used as the parameter to pm2.
I know I can create a wrapper js or bash script to load the variable from .env file and pass it to pm2 but it would be better to have a solution without it.
How can I achieve this?
You can create an ecosystem.config.js file and declare your environment variables under the “env:” attribute, in your case the NODE_APP_INSTANCE can be used to set the number of instances:
module.exports = {
apps : [{
name: "MyApp",
script: "./myapp.js",
env: {
NODE_ENV: "development",
NODE_APP_INSTANCE: "max"
},
env_production: {
NODE_ENV: "production",
}
}]
}
Then call pm2 start or pm2 start /path/to/ecosystem.config.js to load an ecosystem from an other folder.
A better pattern here is to remove dotenv from your code and "require" it on the command line. This makes your code nicely transportable between any environment (including cloud-based) - which is one of the main features of environment variables.
a) code up your .env file alongside your script (e.g. app.js)
b) to run your script without pm2:
node -r dotenv/config app.js
c) in pm2.config.js:
module.exports = {
apps : [{
name : 'My Application',
script : 'app.js',
node_args : '-r dotenv/config',
...
}],
}
and then
pm2 start pm2.config.js
Note: the use of dotenv/config on the command line is one of the best practices recommended by dotenv themselves

how do I make webpack not convert process.env variables to their values during build?

I have the following in one of my project files:
const baas = process.env.DBID;
console.log('baas', baas);
If I run:
cross-env PORT=4000 NODE_ENV=production WEBPACK_CONFIG=browser_prod,server_prod webpack --colors
My server.js file looks like:
const baas = undefined;
console.log('baas', baas);
As expected. However, I want to be able to set the ID when I run the built app not when I build the app, ie:
DBID=someotherid node dist/server.js
So I need webpack to not convert const baas = process.env.DBID to it's value at build time, but rather leave it as is, so the server.js uses it's value at runtime.
How do I do this?
Note: if I manually edit the built server.js and change undefined to process.env.DBID then the run script works and the app uses the env var from run time, but I don't want to edit files after building.
You are using the wrong target.
By default, webpack builds the application to be run in the browser. This means it will mock native node functions like path fs and process
Your target is node, so there is no need to mock these.
Add this to your webpack.config.js
module.exports = {
target: 'node'
};
https://webpack.js.org/concepts/targets/#usage
What you need is process.argv not process.env:
// server.js
const baas = process.argv[0];
console.log('baas', baas);
Then:
node dist/server.js baas_value
For convenience, you can use this module https://www.npmjs.com/package/yargs
I was able to prevent Webpack from converting process.env by accessing it indirectly like this:
const processText = "process";
const _process = global[processText];
app.listen(_process.env.PORT || 2000);
You need to get process indirectly instead of env because the process variable is defined by webpack to be something like /* provided dependency */ var process = __webpack_require__(/*! process/browser */ "process/browser");

How to run a shell command from Grunt task function

I'm trying to move some icons in my app directory based on a function i have inside my Gruntfile.js. Would it be possible to do something like this? I've tried the following (going into dev or staging folder and copying all files to the previous directory), but coudn't get it to work. Thanks in advance.
grunt.registerTask('setAppIcon', 'Task that sets the app icon', function(environment) {
if (environment.toLowerCase() == "development") {
grunt.task.run(['exec:command:cd app/lib/extras/res/icon/ios/dev && cp -a . ../']);
} else if (environment.toLowerCase() == "staging") {
grunt.task.run(['exec:command:cd app/lib/extras/res/icon/ios/staging && cp -a . ../']);
}
});
Yes, it's possible to achieve your requirement, however, when you invoke the grunt.task.run command inside your function (i.e. custom task) you need to provide a reference to a task to run.
If you define a separate Target, (Let's call call them copy_dev and copy_staging - as shown in the example below), for each cd ... && cp ... command in the grunt-exec Task it should work successfully.
Gruntfile.js
The following Gruntfile.js gist shows how this can be achieved:
module.exports = function (grunt) {
grunt.loadNpmTasks('grunt-exec');
grunt.initConfig({
exec: {
copy_dev: {
cmd: 'cd app/lib/extras/res/icon/ios/dev && cp -a . ../'
},
copy_staging: {
cmd: 'cd app/lib/extras/res/icon/ios/staging && cp -a . ../'
}
}
});
grunt.registerTask('setAppIcon', 'Task that sets the app icon', function() {
var environment = process.env.NODE_ENV;
// Exit early if NODE_ENV variable has not been set.
if (!environment) {
grunt.log.writeln(
'\"setAppIcon\"" task failed - NODE_ENV has not been set.'['yellow']
)
return
}
if (environment.toLowerCase() == "development") {
grunt.task.run('exec:copy_dev');
grunt.log.writeln('>> Copying icons from \"dev\"...')
} else if (environment.toLowerCase() == "staging") {
grunt.task.run('exec:copy_staging');
grunt.log.writeln('>> Copying icons from \"staging\"...')
}
});
grunt.registerTask('default', [ 'setAppIcon' ]);
};
Additional notes
Inside the custom task/function named setAppIcon we obtain the current node environment using nodes builtin process.env
When running $ grunt via your CLI (using the gist shown above), and assuming your process.env.NODE_ENV variable has not been set, or it has possibly been unset by running $ unset NODE_ENV, you will see the following message:
"setAppIcon"" task failed - NODE_ENV has not been set.
However, if the process.env.NODE_ENV variable has been set to either development or staging the files will be copied as expected.
For example running either of the following via your CLI will work successfully:
$ export NODE_ENV=development && grunt
or
$ export NODE_ENV=staging && grunt
You will also see either of the following messages logged to the console:
>> Copying icons from "dev"...
or
>> Copying icons from "staging"...
After process.env.NODE_ENV has been set to either development or staging then just running $ grunt via your CLI, will copy files according to which environment is set.

How to auto-reload files in Node.js?

Any ideas on how I could implement an auto-reload of files in Node.js? I'm tired of restarting the server every time I change a file.
Apparently Node.js' require() function does not reload files if they already have been required, so I need to do something like this:
var sys = require('sys'),
http = require('http'),
posix = require('posix'),
json = require('./json');
var script_name = '/some/path/to/app.js';
this.app = require('./app').app;
process.watchFile(script_name, function(curr, prev){
posix.cat(script_name).addCallback(function(content){
process.compile( content, script_name );
});
});
http.createServer(this.app).listen( 8080 );
And in the app.js file I have:
var file = require('./file');
this.app = function(req, res) {
file.serveFile( req, res, 'file.js');
}
But this also isn't working - I get an error in the process.compile() statement saying that 'require' is not defined. process.compile is evaling the app.js, but has no clue about the node.js globals.
A good, up to date alternative to supervisor is nodemon:
Monitor for any changes in your node.js application and automatically restart the server - perfect for development
To use nodemon with version of Node without npx (v8.1 and below, not advised):
$ npm install nodemon -g
$ nodemon app.js
Or to use nodemon with versions of Node with npx bundled in (v8.2+):
$ npm install nodemon
$ npx nodemon app.js
Or as devDependency in with an npm script in package.json:
"scripts": {
"start": "nodemon app.js"
},
"devDependencies": {
"nodemon": "..."
}
node-supervisor is awesome
usage to restart on save for old Node versions (not advised):
npm install supervisor -g
supervisor app.js
usage to restart on save for Node versions that come with npx:
npm install supervisor
npx supervisor app.js
or directly call supervisor in an npm script:
"scripts": {
"start": "supervisor app.js"
}
i found a simple way:
delete require.cache['/home/shimin/test2.js']
If somebody still comes to this question and wants to solve it using only the standard modules I made a simple example:
var process = require('process');
var cp = require('child_process');
var fs = require('fs');
var server = cp.fork('server.js');
console.log('Server started');
fs.watchFile('server.js', function (event, filename) {
server.kill();
console.log('Server stopped');
server = cp.fork('server.js');
console.log('Server started');
});
process.on('SIGINT', function () {
server.kill();
fs.unwatchFile('server.js');
process.exit();
});
This example is only for one file (server.js), but can be adapted to multiple files using an array of files, a for loop to get all file names, or by watching a directory:
fs.watch('./', function (event, filename) { // sub directory changes are not seen
console.log(`restart server`);
server.kill();
server = cp.fork('server.js');
})
This code was made for Node.js 0.8 API, it is not adapted for some specific needs but will work in some simple apps.
UPDATE:
This functional is implemented in my module simpleR, GitHub repo
nodemon came up first in a google search, and it seems to do the trick:
npm install nodemon -g
cd whatever_dir_holds_my_app
nodemon app.js
nodemon is a great one. I just add more parameters for debugging and watching options.
package.json
"scripts": {
"dev": "cross-env NODE_ENV=development nodemon --watch server --inspect ./server/server.js"
}
The command: nodemon --watch server --inspect ./server/server.js
Whereas:
--watch server Restart the app when changing .js, .mjs, .coffee, .litcoffee, and .json files in the server folder (included subfolders).
--inspect Enable remote debug.
./server/server.js The entry point.
Then add the following config to launch.json (VS Code) and start debugging anytime.
{
"type": "node",
"request": "attach",
"name": "Attach",
"protocol": "inspector",
"port": 9229
}
Note that it's better to install nodemon as dev dependency of project. So your team members don't need to install it or remember the command arguments, they just npm run dev and start hacking.
See more on nodemon docs: https://github.com/remy/nodemon#monitoring-multiple-directories
Nodemon has been the go to for restarting server for file changes for long time. Now with Node.js 19 they have introduced a --watch flag, which does the same [experimental]. Docs
node --watch index.js
node-dev works great. npm install node-dev
It even gives a desktop notification when the server is reloaded and will give success or errors on the message.
start your app on command line with:
node-dev app.js
There is Node-Supervisor that you can install by
npm install supervisor
see http://github.com/isaacs/node-supervisor
You can use nodemon from NPM.
And if you are using Express generator then you can using this command inside your project folder:
nodemon npm start
or using Debug mode
DEBUG=yourapp:* nodemon npm start
you can also run directly
nodemon your-app-file.js
Hope this help.
There was a recent (2009) thread about this subject on the node.js mailing list. The short answer is no, it's currently not possible auto-reload required files, but several people have developed patches that add this feature.
With Node.js 19 you can monitor file changes with the --watch option. After a file is changed, the process is restarted automatically, reflecting new changes.
node --watch server.js
yet another solution for this problem is using forever
Another useful capability of Forever is that it can optionally restart
your application when any source files have changed. This frees you
from having to manually restart each time you add a feature or fix a
bug. To start Forever in this mode, use the -w flag:
forever -w start server.js
Here is a blog post about Hot Reloading for Node. It provides a github Node branch that you can use to replace your installation of Node to enable Hot Reloading.
From the blog:
var requestHandler = require('./myRequestHandler');
process.watchFile('./myRequestHandler', function () {
module.unCacheModule('./myRequestHandler');
requestHandler = require('./myRequestHandler');
}
var reqHandlerClosure = function (req, res) {
requestHandler.handle(req, res);
}
http.createServer(reqHandlerClosure).listen(8000);
Now, any time you modify myRequestHandler.js, the above code will no­tice and re­place the local re­questHandler with the new code. Any ex­ist­ing re­quests will con­tin­ue to use the old code, while any new in­com­ing re­quests will use the new code. All with­out shut­ting down the serv­er, bounc­ing any re­quests, pre­ma­ture­ly killing any re­quests, or even re­ly­ing on an in­tel­li­gent load bal­ancer.
I am working on making a rather tiny node "thing" that is able to load/unload modules at-will (so, i.e. you could be able to restart part of your application without bringing the whole app down).
I am incorporating a (very stupid) dependency management, so that if you want to stop a module, all the modules that depends on that will be stopped too.
So far so good, but then I stumbled into the issue of how to reload a module. Apparently, one could just remove the module from the "require" cache and have the job done. Since I'm not keen to change directly the node source code, I came up with a very hacky-hack that is: search in the stack trace the last call to the "require" function, grab a reference to it's "cache" field and..well, delete the reference to the node:
var args = arguments
while(!args['1'] || !args['1'].cache) {
args = args.callee.caller.arguments
}
var cache = args['1'].cache
util.log('remove cache ' + moduleFullpathAndExt)
delete( cache[ moduleFullpathAndExt ] )
Even easier, actually:
var deleteCache = function(moduleFullpathAndExt) {
delete( require.cache[ moduleFullpathAndExt ] )
}
Apparently, this works just fine. I have absolutely no idea of what that arguments["1"] means, but it's doing its job. I believe that the node guys will implement a reload facility someday, so I guess that for now this solution is acceptable too.
(btw. my "thing" will be here: https://github.com/cheng81/wirez , go there in a couple of weeks and you should see what I'm talking about)
solution at:
http://github.com/shimondoodkin/node-hot-reload
notice that you have to take care by yourself of the references used.
that means if you did : var x=require('foo'); y=x;z=x.bar; and hot reloaded
it.
it means you have to replace the references stored in x, y and z. in the hot reaload callback function.
some people confuse hot reload with auto restart
my nodejs-autorestart module also has upstart integration to enable auto start on boot.
if you have a small app auto restart is fine, but when you have a large app hot reload is more suitable. simply because hot reload is faster.
Also I like my node-inflow module.
Here's a low tech method for use in Windows. Put this in a batch file called serve.bat:
#echo off
:serve
start /wait node.exe %*
goto :serve
Now instead of running node app.js from your cmd shell, run serve app.js.
This will open a new shell window running the server. The batch file will block (because of the /wait) until you close the shell window, at which point the original cmd shell will ask "Terminate batch job (Y/N)?" If you answer "N" then the server will be relaunched.
Each time you want to restart the server, close the server window and answer "N" in the cmd shell.
my app structure:
NodeAPP (folder)
|-- app (folder)
|-- all other file is here
|-- node_modules (folder)
|-- package.json
|-- server.js (my server file)
first install reload with this command:
npm install [-g] [--save-dev] reload
then change package.json:
"scripts": {
"start": "nodemon -e css,ejs,js,json --watch app"
}
now you must use reload in your server file:
var express = require('express');
var reload = require('reload');
var app = express();
app.set('port', process.env.PORT || 3000);
var server = app.listen(app.get('port'), function() {
console.log( 'server is running on port ' + app.get('port'));
});
reload(server, app);
and for last change, end of your response send this script:
<script src="/reload/reload.js"></script>
now start your app with this code:
npm start
You can do it with browser-refresh. Your node app restarts automatically, your result page in browser also refreshes automatically. Downside is that you have to put js snippet on generated page. Here's the repo for the working example.
const http = require('http');
const hostname = 'localhost';
const port = 3000;
const server = http.createServer((req, res) => {
res.statusCode = 200;
res.setHeader('Content-Type', 'text/html; charset=UTF-8');
res.write('Simple refresh!');
res.write(`<script src=${process.env.BROWSER_REFRESH_URL}></script>`);
res.end();
})
server.listen(port, hostname, () => {
console.log(`Server running at http://${hostname}:${port}/`);
if (process.send) {
process.send({ event: 'online', url: `http://${hostname}:${port}/` })
}
});
Not necessary to use nodemon or other tools like that. Just use capabilities of your IDE.
Probably best one is IntelliJ WebStorm with hot reload feature (automatic server and browser reload) for node.js.
I have tried pm2 : installation is easy and easy to use too; the result is satisfying. However, we have to take care of which edition of pm2 that we want. pm 2 runtime is the free edition, whereas pm2 plus and pm2 enterprise are not free.
As for Strongloop, my installation failed or was not complete, so I couldn't use it.
If your talking about server side NodeJS hot-reloading, lets say you wish to have an Javascript file on the server which has an express route described and you want this Javascript file to hot reload rather than the server re-starting on file change then razzle can do that.
An example of this is basic-server
https://github.com/jaredpalmer/razzle/tree/master/examples/basic-server
The file https://github.com/jaredpalmer/razzle/blob/master/examples/basic-server/src/server.js will hot-reload if it is changed and saved, the server does not re-start.
This means you can program a REST server which can hot-reload using this razzle.
it's quite simple to just do this yourself without any dependency... the built in file watcher have matured enough that it dose not sucks as much as before
you don't need any complicated child process to spawn/kill & pipe std to in/out... you just need a simple web worker, that's all! A web Worker is also what i would have used in browsers too... so stick to web techniques! worker will also log to the console
import { watch } from 'node:fs/promises'
import { Worker } from 'node:worker_threads'
let worker = new Worker('./app.js')
async function reloadOnChange (dir) {
const watcher = watch(dir, { recursive: true })
for await (const change of watcher) {
if (change.filename.endsWith('.js')) {
worker.terminate()
worker = new Worker('./app.js')
}
}
}
// All the folder to watch for
['./src', './lib', './test'].map(reloadOnChange)
this might not be the best solution where you use anything else other than javascript and do not depend on some build process.
Use this:
function reload_config(file) {
if (!(this instanceof reload_config))
return new reload_config(file);
var self = this;
self.path = path.resolve(file);
fs.watchFile(file, function(curr, prev) {
delete require.cache[self.path];
_.extend(self, require(file));
});
_.extend(self, require(file));
}
All you have to do now is:
var config = reload_config("./config");
And config will automatically get reloaded :)
loaddir is my solution for quick loading of a directory, recursively.
can return
{ 'path/to/file': 'fileContents...' }
or
{ path: { to: { file: 'fileContents'} } }
It has callback which will be called when the file is changed.
It handles situations where files are large enough that watch gets called before they're done writing.
I've been using it in projects for a year or so, and just recently added promises to it.
Help me battle test it!
https://github.com/danschumann/loaddir
You can use auto-reload to reload the module without shutdown the server.
install
npm install auto-reload
example
data.json
{ "name" : "Alan" }
test.js
var fs = require('fs');
var reload = require('auto-reload');
var data = reload('./data', 3000); // reload every 3 secs
// print data every sec
setInterval(function() {
console.log(data);
}, 1000);
// update data.json every 3 secs
setInterval(function() {
var data = '{ "name":"' + Math.random() + '" }';
fs.writeFile('./data.json', data);
}, 3000);
Result:
{ name: 'Alan' }
{ name: 'Alan' }
{ name: 'Alan' }
{ name: 'Alan' }
{ name: 'Alan' }
{ name: '0.8272748321760446' }
{ name: '0.8272748321760446' }
{ name: '0.8272748321760446' }
{ name: '0.07935990858823061' }
{ name: '0.07935990858823061' }
{ name: '0.07935990858823061' }
{ name: '0.20851597073487937' }
{ name: '0.20851597073487937' }
{ name: '0.20851597073487937' }
another simple solution is to use fs.readFile instead of using require
you can save a text file contaning a json object, and create a interval on the server to reload this object.
pros:
no need to use external libs
relevant for production (reloading config file on change)
easy to implement
cons:
you can't reload a module - just a json containing key-value data
For people using Vagrant and PHPStorm, file watcher is a faster approach
disable immediate sync of the files so you run the command only on save then create a scope for the *.js files and working directories and add this command
vagrant ssh -c "/var/www/gadelkareem.com/forever.sh restart"
where forever.sh is like
#!/bin/bash
cd /var/www/gadelkareem.com/ && forever $1 -l /var/www/gadelkareem.com/.tmp/log/forever.log -a app.js
I recently came to this question because the usual suspects were not working with linked packages. If you're like me and are taking advantage of npm link during development to effectively work on a project that is made up of many packages, it's important that changes that occur in dependencies trigger a reload as well.
After having tried node-mon and pm2, even following their instructions for additionally watching the node_modules folder, they still did not pick up changes. Although there are some custom solutions in the answers here, for something like this, a separate package is cleaner. I came across node-dev today and it works perfectly without any options or configuration.
From the Readme:
In contrast to tools like supervisor or nodemon it doesn't scan the filesystem for files to be watched. Instead it hooks into Node's require() function to watch only the files that have been actually required.
const cleanCache = (moduleId) => {
const module = require.cache[moduleId];
if (!module) {
return;
}
// 1. clean parent
if (module.parent) {
module.parent.children.splice(module.parent.children.indexOf(module), 1);
}
// 2. clean self
require.cache[moduleId] = null;
};

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