I have the following code:
exec('kubectl exec -it -n production my-kubectl-pod-id bash',
function (e, stdo, stde) {
console.log(stdo)
})
However it doesnt work. When it runs, the program just stalls and I can't see the command line prompt at all, but i can type new lines but it is not running any commands i type.
I'm expecting to enter a pod and be able to work inside the pod however i need.
Is there a way to do this from inside a node script? Or a way for the script to end and then run that command?
Related
I am very new to coding, and have just installed VS Code, and installed Node.js as well as Git Bash. I was working on a project, but couldn't console.log anything as I always received the following error when using Git Bash:
bash: syntax error near unexpected token `validateCred' (One of the
variables I used)
I created a new JS file, and ran the following code:
const hello = 'hello world';
I still received the same bash error. I have tried replacing my code with code that I know works and still receive the same errors.I have also tried using Powershell as my terminal, but receive the following errors every time:
batch : The term 'batch' is not recognized as the name of a cmdlet,
function, script file, or operable program. Check the spelling of the
name, or if a path was included, verify that the path is correct and
try again.
I am at a loss, and I'm sure it's something really simple, but I can't seem to figure it out!
A Bash shell expects you to enter Bash code and not JavaScript code.
If you want to run JavaScript code then you need to run it in Node.js and not in Bash.
Generally, the command node will launch Node.js in a Bash shell. (Assuming it is installed on the $PATH).
Having this bash_profile commands, trying to run backend and frontend server in one single alias command i.e ins
alias is='ivui && npm run start:backend'
alias ib='ivbe && npm run start:dev'
alias ins='ib && is'
is referring to a different project folder and it starts the server and ib is also referring to a different folder and server. Trying to concat both, but the first one only triggers and concat of && is not executed.
Concat npm helps in combining both servers from single project folder, but wondering how we can get this done using bash_profile? so that by executing just ins, it must start backend server first and frontend also.
The reason your double alias command (ib && is) does not work is because, as per man bash:
Aliases allow a string to be substituted for a word when it is used as
the first word of a simple command.
Stands to reason that if you run ib && is where both ib and is are aliases, it will only run ib.
With that out of the way, there is have a different and, I believe, better solution to your problem. You can use screen to run those 2 commands in the background and also, as a bonus, have the ability to watch their terminal output any time you want.
The idea is this: 1. Start a screen session; 2. Open two windows inside that session; 3. Run npm run start:backend in 1st window and run npm run start:dev in the second window.
Here is what you need:
screen -S Servers -t backend_window -A -d -m
screen -S Servers -X screen -t dev_window
This will start a screen session with backend_window and dev_window inside it. Now you just need to run your 2 commands inside those windows:
screen -S Servers -p backend_window -X stuff $'npm run start:backend\n'
screen -S Servers -p dev_window -X stuff $'npm run start:dev\n'
Now both your npm commands are running in the background at the same time. You can just put these 4 lines into your .bashrc file and it will launch on log in.
But the best part about this approach is you can visually see what's going on with those npm commands by attaching the screen and looking inside those windows. Just run:
screen -rx Servers
This will show you your first window by default. Let's split the screen and show both windows side by side:
Ctr-A + | <- will split the screen into 2 sections
Ctr-A + Tab <- will shit cursor to the new section
Ctr-A + " <- will show you your 2 windows, just pick the dev
All this will give you this view
Keep in mind that both your npm commands will continue to run even after you log out. To kill them, either attach the screen as described above and then Ctrl-C both processes. Or just run killall screen and they will just die.
You could create a function and add your aliases inside, for example,
stopdev () (
cd "$HOME/website" && {
make website_stop
ret=$?
make backend_stop && return $ret
}
)
This example also has a return code, and has a subshell called to run the function, so the filepath is not $HOME/website after the function is called.
More information on the following webpage,
https://unix.stackexchange.com/questions/266063/why-cant-i-call-two-aliases-with
I am trying to run my node.js application from a script I have written:
echo "Starting node application"
sudo node /home/pi/PPBot/bot.js
exit 0
I run the script like this: sudo /etc/init.d/botscript
The output when running the script is:
Start node application
sudo: node: command not found
I have also tried replacing node by /home/pi/.nvm/versions/node/v.8.11.3/bin/node but this resulted in the same output.
I have already installed NodeJS through NVM. Simply using the command node bot.js works from the command line. However as can be seen above it does not work through the script.
if you want to run a simple node js file then use the command
-> node filename
ex.: node server.js
if you want to run a node js file with nodemon then use the command
-> nodemon filename
ex.: nodemon server.js
This is kind of a doozy. This issue is most likely server related and so my first recourse was AskUbuntu over here.
I'm trying to have crontab or rc.local or init.d to start a forever script on boot. It attaches a server to a port I can ping with some information and have it run a headless browser for me.
That said, it seems that I'm unable to get a response from Node.js's spawn():
var CASPER_PATH = '/home/ubuntu/dev/casperjs/bin/casperjs'; // actual binary location, not a symlink
var SCRIPTS_PATH = '/home/custom_user/endpoints/server.js';
var fileName = req.body.source + '_' + req.body.type + '.coffee'; // looks like: mysource_my_scrape_type.coffee
var scrapeId = 'test_scrape';
var user = 'user123';
var pass = 'pass123';
if (fs.existsSync(SCRIPTS_PATH + fileName)) {
// If file is in place, spawn casperjs
var sP = spawn(CASPER_PATH,
[SCRIPTS_PATH + fileName, '--ssl-protocol=any', '--user='+user, '--scrapeId='+scrapeId, '--pass='+pass],
{ detached: true },
function (err, stdout, stderr) {});
sP.stdout.on('data', function(data) { console.log('stdout', data.toString('utf8')); });
sP.stderr.on('data', function(data) { console.log('stderr', data.toString('utf8')); });
sP.stdout.on('close', function(code) { console.log('close', code); });
res.send({ scheduled: true, key: scrapeId });
} else {
res.send({ scheduled: false, error: 'Incorrect source, type or the script is missing.' });
}
Before I added the PHANTOMJS_EXECUTABLE env to crontab or rc.local (doesnt seem to matter no matter the user level), stdout was useful:
stdout Fatal: [Errno 2] No such file or directory; did you install
phantomjs?
close false
Now that the environment var is there, there is no output at all after spawn().
Mind you, Casper starts up just fine if a user (of any privilege level) runs node/forever from bash.
How can I see why spawn() is failing?
This actually looks like a combo-bug between forever, spawn and casperjs (maybe phantomjs).
I was able to reproduce your problem, here is the full code of my test application.
You didn't show the full code, so my guess is that you have an express application and there is a special URL to run the casperjs script.
I build a simple app like this and it behaved this way:
Just start app with node script.js (script.js is the express app which runs the casperjs script in server.js) - it works OK, renders response and writes output from the child process event handlers to console
Start app as root with init.d script - doesn't work, once the child is spawned, no event handlers are triggered
Start app as root with init.d script, replace casperjs with echo - the same, doesn't work (see, here we have this problem with just forever running as root, spawn and echo)
Start app as a regular user (not root) with init.d, replace casperjs with 'echo' - it works, event handlers are triggered, here I was almost sure the issue is solved, but ... :(
Start app as a regular user (not root) with init.d, put back casperjs - it doesn't work again, event handlers are not triggered
The practical solution to this it to use pm2, I did this:
# install pm2
sudo npm install -g pm2
# generate init.d scripts for pm2
# this command will fail, but hint about the correct format with sudo
pm2 startup ubuntu
# do this in the folder with your application
pm2 start script.js
# remember your application
pm2 save
# also useful
# sudo service stop/start/restart pm2
# pm2 stop/start/restart script
Now pm2 will start automatically with the system and it will launch your application. Everything works, child process event handlers are triggered.
I did not understand your requirement completely. But i do have a similar situation with Ubuntu headless server.
what i am trying to do here is what i did
First, How is my crontab ?
crontab -u USER -e
#reboot exec sudo -u USER /bin/bash /home/USER/SHELL_SCRIPT.sh
See, here i am actually starting a shell script, and not a node server
Now inside this shell script(SHELL_SCRIPT.sh)
#! /bin/bash
# SHELL_SCRIPT.sh
cd /home/USER/
/home/USER/.npm-packages/bin/forever start -p /home/USER -a -d --watch false --pidFile /home/USER/forever.pid -l /home/USER/forever.log -o /home/USER/forever.out -e /home/USER/forever.err /home/USER/MY_NODE.js
and even inside my MY_NODE.js i follow absolute path, i just ignore $PATH, and don't use that.
Inside this node server, I do 100's of spawn
Now, i did this around 2 years back, so if you ask me why do this way, which i cannot answer
Node n00b here. I just installed node on my windows desktop and I'm wondering where I should enter my node commands and why... I have three options (see below). Oh, and if one of these (i.e. node.exe) is not intended for entering node commands, what is it for?
I have looked at the nodejs.org docs and I don't see a clear overview/explanation of what each of these are for and why it's recommended to use one over the other.
Thanks for any insight.
================================================
1) Windows Command Line:
2) Node.js command prompt:
3) Node exe
#1 This is simply window's cmd, you can type node --help there to get a general overview of what you can do with node
#2 Also cmd but with some extra configuration, when you view the properties you'll see it's; C:\Windows\System32\cmd.exe /k "C:\Program Files\nodejs\nodevars.bat" Which basically means it runs cmd with a .bat script, that sets some environment variables, changes the title and prints some welcome message.
#3 This is NodeJS' REPL which evaluates JavaScript within NodeJS' context. ( This is the same as running node from cmd )
Usually you don't enter your code directly, but put it in a file instead. Create this file with the name hello.js:
console.log("Hello World!");
Switch to the directory of your file:
cd C:\Users\yourname\yourdirectory
Then run it with the node command:
node hello.js
And you should get the following output:
Hello World!