NodeJs Testrunner freezes / stops when setting up Express server - javascript

I'm using Node v18 with the experimental testrunner. I use express as a dev dependency for http integration tests which works fine but there is one test freezing or stopping the testrunner ( it doesn't continue )
I'm using TS but can also reproduce it with JS, the test file HttpTests.js contains
import assert from 'assert/strict';
import express from 'express';
import test from 'node:test';
test('Http', async () => {
const server = express();
server.listen(3000);
assert.ok(false);
});
Running this with the npm script "test": "node --test $(find . -name '*Tests.js')" breaks the test runner.
Any ideas what is wrong or missing?
Why am I not using the default execution model?
Since I'm using TS I had to find a way to use ts-node with the testrunner. You can find more information here
https://github.com/nodejs/node/issues/43675
So currently my TS project is using this npm script, which works fine
Reproduction
I created a minimal reproduction repository with and without TypeScript
https://github.com/matthiashermsen/reproduce-broken-test-ts
https://github.com/matthiashermsen/reproduce-broken-test-js
For reproduction purposes run mkdir reproduction && cd reproduction && npm init -y && npm install express. After that create a test directory with a file HttpTests.js containing the content as shown above. Change the package.json to
{
"name": "reproduction",
"type": "module",
"scripts": {
"test": "node --test $(find . -name '*Tests.js')"
}
}
and run the script, the testrunner should not finish.
The testrunner is still experimental
Yes I know. But there are many tests in the project that work perfectly fine. Some sample code
await t.test('subtest - saves data.', async () => {
const expectedResult = {};
const api = express();
const port = await getRandomPort();
const server = api
.use(express.json())
.post('/save', (request, response) => {
response.json(expectedResult);
})
.listen(port);
const httpDataProvider = new HttpDataProvider({ url: `http://localhost:${port}` });
const actualResult = await httpDataProvider.saveSomething();
assert.deepEqual(actualResult, expectedResult);
server.close();
});

The issue is the async activity that you start (server.listen()) but don't stop before the test errors out (by an exception thrown by assert.ok(false)).
Your second test case will probably also stall if actualResult doesn't deep-equal expectedResult because of the same issue (server.close() won't be called).
A workaround would be to always make sure the server gets closed in the end:
test('Http', async () => {
const app = express();
const server = app.listen(3000);
try {
assert.ok(false);
} finally {
server.close();
}
});
Most test frameworks provide "before/after" functionality that can be used to set up or tear down auxiliary objects before and after a test.

Related

starting docker backend from electron-vue frontend

I am building an app based on electron vue. My electron app is supposed to start its backend running from a docker container. To do this I call a bash file with the docker run command in it.
const {spawn} = require('child_process')
const dckrrn = spawn('sh', dockercall)
dckrrn.stdout.on('data', (data) => {
console.log(`stdout: ${data}`)
})
dckrrn.stderr.on('data', (data) => {
console.log(`stderr: ${data}`)
})
dckrrn.on('close', (code) => {
console.log(`child process exited with code ${code}`)
})
Everything works fine in development mode but when I try it in my packaged app it complains:
stderr: pathtobashscript.sh line 13 docker: command not found.
It seems for some reason the spawned child process is unaware of the docker installation on the system. What am I doing wrong? What is the correct way to achieve this? Should I try the execfile function? Thanks for your time!
PS:
Sorry that I cannot provide you with a reproducible example, the total app with backend is around 7gb.
PPS:
some interesting sidenotes:
which docker
returns nothing, and:
pwd
returns: /
PPPS: I tried including the docker path at the beginning of my bash script but with no success:
PATH="/usr/local/bin/docker:${PATH}"
export PATH
4PS:
I managed to get the docker running by adding shell: true to the environment. The problem I have now is that the docker folder mappings do not work anymore. So I guess I also have to make them visible to the env somehow.
const {spawn} = require('child_process')
const dckrrn = spawn('sh', dockercall, {
env: {
shell: true
}
})
solved by adding shell: true to the env:
const {spawn} = require('child_process')
const dckrrn = spawn('sh', dockercall, {
env: {
shell: true
}
})

"fetch is not found globally and no fetcher passed" when using spacejam in meteor

I'm writing unit tests to check my api. Before I merged my git test branch with my dev branch everything was fine, but then I started to get this error:
App running at: http://localhost:4096/
spacejam: meteor is ready
spacejam: spawning phantomjs
phantomjs: Running tests at http://localhost:4096/local using test-in-console
phantomjs: Error: fetch is not found globally and no fetcher passed, to fix pass a fetch for
your environment like https://www.npmjs.com/package/unfetch.
For example:
import fetch from 'unfetch';
import { createHttpLink } from 'apollo-link-http';
const link = createHttpLink({ uri: '/graphql', fetch: fetch });
Here's a part of my api.test.js file:
describe('GraphQL API for users', () => {
before(() => {
StubCollections.add([Meteor.users]);
StubCollections.stub();
});
after(() => {
StubCollections.restore();
});
it('should do the work', () => {
const x = 'hello';
expect(x).to.be.a('string');
});
});
The funniest thing is that I don't even have graphql in my tests (although, I use it in my meteor package)
Unfortunately, I didn't to find enough information (apart from apollo-link-http docs that has examples, but still puzzles me). I did try to use that example, but it didn't help and I still get the same error
I got the same error importing a npm module doing graphql queries into my React application. The app was compiling but tests were failing since window.fetch is not available in the Node.js runtime.
I solved the problem by installing node-fetch https://www.npmjs.com/package/node-fetch and adding the following declarations to jest.config.js:
const fetch = require('node-fetch')
global.fetch = fetch
global.window = global
global.Headers = fetch.Headers
global.Request = fetch.Request
global.Response = fetch.Response
global.location = { hostname: '' }
Doing so we instruct Jest on how to handle window.fetch when it executes frontend code in the Node.js runtime.
If you're using nodejs do the following:
Install node-fetch
npm install --save node-fetch
Add the line below to index.js:
global.fetch = require('node-fetch');
The problem is this: fetch is defined when you are in the browser, and is available as fetch, or even window.fetch
In the server it is not defined, and either needs to be imported explicity, or a polyfill like https://www.npmjs.com/package/unfetch (as suggested in the error message) needs to be imported by your test code to make the problem go away.

What is the difference to run React server-side rendering locally and on real NodeJS server (IBM Bluemix)

I created a simple react app with serverside rendering using this workshop git as a base with my minor changes.
So when I run locally NODE_ENV=server node server.js it works fine. But my attempts to deploy this app on a trial of Bluemix the Nodejs server failed. Here's a log :
Here is my server.js code:
require('babel-register')
const express = require('express')
const React = require('react')
const ReactDOMServer = require('react-dom/server')
const ReactRouter = require('react-router')
const StaticRouter = ReactRouter.StaticRouter
const _ = require('lodash')
const fs = require('fs')
const PORT = 5050
const baseTemplate = fs.readFileSync('./index.html')
const template = _.template(baseTemplate)
const App = require('./js/App').default
const server = express()
server.use('/_public', express.static('./_public'))
server.use((req, res) => {
const context = {}
const body = ReactDOMServer.renderToString(
React.createElement(StaticRouter, {location: req.url,
context: context},
React.createElement(App))
)
res.write(template({body: body}))
res.end()
})
console.log('listening on port', PORT)
server.listen(PORT)
P.S. It's obvious that it doesn't understand ES6 syntax in js/App.js, but on my local server it works.
By default NODE_ENV=production but according to Bluemix docs I created a file in .profile.d directory
node_env.sh code:
export NODE_ENV=server;
But I'm not sure if this file changes node_env.
I'm hoping someone more knowledgeable than me can offer a better solution, but here is what I did to make your app work. There is probably a better answer.
Assuming that you do NOT want to run in production mode...
1) server.js: Listen to the port as set in the PORT env var.
server.listen(process.env.PORT || PORT)
2) package.json: Add start command in scripts
"start": "babel-node server.js --presets es2015,stage-2"
3) Get babel-cli
npm install --save-dev babel-cli
npm install --save-dev babel-preset-es2015 babel-preset-stage-2
4) Create a manifest.yml to set CF properties
applications:
- name: rvennam-node-react
memory: 1G
disk_quota: 2G
env:
NPM_CONFIG_PRODUCTION: false
NODE_ENV: dev
5) remove eslint dependencies from devDependencies in package.json (there was a mismatch)
Again, this is assuming you want to run on Bluemix under dev mode. If you wanted production on Bluemix, I would think you would want to use webpack to build locally, and then push and serve your dist directory.

Shell.js async build: wait until meteor is listening to open meteor shell, run command, exit

My goal is to do the following steps in my "bundle" process to export an electron app:
open meteor directory
run meteor
when meteor is listening, open the meteor shell
pass the "electrify" command to meteor shell
when electrify build is complete, return.
So far, I have the following
require('shelljs/make');
require('shelljs/global');
var path = require('path');
target.all = function () {
target.bundle();
}
target.bundle = function () {
console.log('Building for architecture: ' + process.platform + platform.arch);
var meteorPath = path.join(__dirname, 'meteor');
cd(meteorPath);
// this runs for a while, make it asyncronous
var meteorCommand = exec('meteor', { async: true });
meteorCommand.stdout.on('data', function (data) {
// ???
});
}
This yields expected output to stdout.
Building for: darwinx64
[[[[[ ~/Code/test/meteor-test ]]]]]
=> Started proxy.
=> Started MongoDB.
=> Babel active on file extensions: es6.js, es6, jsx
I20150728-10:06:05.899(-4)? electrify: installing electrified dependencies
I20150728-10:06:07.005(-4)? electrify: launching electron
=> Started your app.
=> App running at: http://localhost:3000/
However, I am facing a problem... meteor has a startup process and needs to be running before I can use meteor shell, which is the final step where it says "App running at:".
How can I wait for this event to happen before opening the meteor shell?

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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