I am running a nodejs server locally with Firebase emulators (using firebase emulators:start). I have another version running on google cloud functions - but I also need something running locally.
When errors happen, my whole node process dies, and the emulator dies etc... and I have to go back and restart the process manually. Is there a way to automatically restart it when an error happens, such as using forever? I tried with something like forever start firebase emulators:start but that didn't work.
Due to how Firebase is built and operates, it does not support any such functionality of staying awake as a process virtually non-stop. You would most likely need to refactor your code in such a way that the process you need to keep alive indefinitely is separated from your code hosted by the firebase emulator.
Related
I am using pm2 to keep a script running and making api calls in an interval. Sometimes the api calls fail, the script is running and not restarted but the calls just dont go out. I set up a health monitor in node.js to inform me whenever these api calls cease.
Now whenever I see downtime I go into the pm2 dashboard and restart my app. I would like to skip this step and have my health monitor just make a call to the pm2 instance that it should restart exactly like the dashboard is doing.
Is this possible? If so how can it be done? I see some pm2.restart options in the docs but Im not sure how this is supposed to occur from a different machine.
I have a Google VM, and i can start a web server. The command i issue is: python server.py.
My plan is to have the application running.
Since i will eventually close my pc (and thus the terminal), will the application continue running normally?
Or, do i have to start the server and then use disown, to make the app run in the background?
NOTE: If the second option is the case, does this mean that when i re-log in, and i want to shut down the server, the only way to do it is with pkill?
I'm newbie using GCP and his Compute Engine Service. I've deploy a Linux Ubuntu Image an it's running like a charm, but I have a issue running Node JS backend.
Let me explain it better:
I'm connecting using Web Browser SSH terminal or GCloud Shell ssh, and it way works running node app.js my backend starts working. But after a time, the sessions stop and my backend service stop working as well. At this time every time when I need to work have to re-activate the service each time.
How could I do for this service works in background and not depends that my ssh terminal are opened?
Thanks a lot in advance.
What actually happen is you are starting your nodejs application using an client which is parent process. So if after sometime the connection is lost of some xyz seconds the parent process dies killing your node application. Now what you can do is use screen. On ubuntu you would do something like this.
sudo apt-get install screen
after successful install run the screen command. Now you will be thrown a brand new terminal. Here you can run your nodejs code which will never die. Since screen runs your application in background. More information here
A good solution could be to use a startup script. To insert a startup script into your already created instance you need to go to this link [1]. When you have your startup script inserted in the metadata field you just need to restart your Instance and then should work perfectly without depending of the ssh session.
[1] https://cloud.google.com/compute/docs/startupscript#startupscriptrunninginstances
I've created this npm package, to make your node app run as a service on your linux machine. Please try it out.
It creates a systemctl service on your machine and runs it as a background service.
I've written two simple Node.js apps, each of which run a server on a port (1337 and 1338), and using PM2 (and Keymetrics) to keep them alive, but every few days all three Node.js apps (including PM2) crash simultaneously. I'm fairly new to Node.js and am not sure how to investigate the source of the problem.
DETAILS:
The two servers respond to incoming GET requests. One is to automatically do a GIT fetch/pull in response to a Bitbucket trigger, and the other converts a URL to PDF and sends the PDF back to the browser (using wkhtmltopdf). They both work fine while they're running.
I'm running Node.js v0.12.4.
When the three apps go down, my first indication is from my Uptime (https://github.com/fzaninotto/uptime) instance on OpenShift which emails me to say one of my Node.js servers is down, returning "connect ECONNREFUSED".
A couple of minutes later Keymetrics emails me saying "Agent is offline: Keymetrics Agent seems to be offline".
In other words, ALL my node.js stuff seems to go down at the same time; neither of the two apps nor even PM2 are running. I thought Node spawned a process for each app, so how could they all go down at once?
WHAT I'VE TRIED:
I've tried digging through the ~/.pm2/pm2.log but haven't been able to find anything useful in there. Maybe I just don't know what to look for.
$ pm2 resurrect always brings everything back to life just fine.
Please upgrade to latest PM2 version:
$ npm install pm2 -g
$ pm2 update
I have a website already developed with node.js and sails.js on "Compute Engine" but to start it, necessarily I have to write "node app.js" in the SSH console of browser. But there is a problem (since I am new to Linux and Google Cloud :)), if I want my Node app it keep online, the SSH window must be open, if I close, the Node application will terminate, like Ctrl+c. So it makes no sense to have my computer turned on, just to have the active window. So, how to keep my NodeJS app online without being in the presence of SSH console?. I know the question is illogic to some, but I would appreciate if you help me. Thanks
First of all it is not related to Compute Engine nor Node.js.
You mention that the application will terminate if you press ctrl+c and that's correct because you are running your application in the foreground instead of background. To run your application in the background you can either launch your app like this:
node app.js &
Or you can launch with node app.js and then press ctrl+z.
But just sending the application to the background wouldn't help. As soon as you disconnect from your ssh session, all programs started (background or foreground) will receive a HUP signal, in node.js you can handle that signal but the default behaviour is to close:
On non-Windows platforms, the default behaviour of SIGHUP is to terminate node
One thing that you can do to ignore the SIGHUP signal is running your app as follows:
nohup node app.js &
If you do this, your application will continue to run even when you close your ssh session. Another way to achieve this is by using the screen.
This will help you on very early stage and for development but I don't recommend using neither of these things for production. Eg: if your application crash it should be restarted. The recommended way is to use a service manager that comes with the OS: upstart, systemd, init, to name a few.
You can install forever module (https://www.npmjs.com/package/forever) to your Google compute engine using SSH window.
npm install forever -g
Then, in your node server directory, execute your server using forever.
forever start [YOUR_SERVER_FILE.js]
Now, if you close the SSH window, your node server is still on !!
Good luck!
The best solution would be using a module called forever:
https://www.npmjs.com/package/forever
You can use it this way:
forever start your_script.js