I wrote a WhatsApp bot using the whatsapp-web.js module. My program only runs locally when I start it. But it should run 24/7. Can somebody help me? And how exactly do I have to proceed?
There's a lot to unpack here. I'm going to assume from the nature of your question that you're new to javascript and node development, so welcome!
Normally when we have an application that we want to have run "24/7" we have to deploy that application to a server, meaning a machine that lives somewhere on the internet. We do this because our local machines turn off, or are rebooted, or loose power. If we want something to run all the time, we'll typically put it on a machine that's running all the time.
There are a ton of options for this, "cloud computing" companies like AWS, Google GCP, Azure, DigitalOcean, Heroku, etc...
Since there are too many options to review each one, I'll describe how I like to do it.
I prefer to use a virtual machine deployed to a cloud provider. Most of them have a free tier where you can run a small, low powered machine for free. This should work fine for your chatbot.
Sign up for an account with, for example, Google, and create a free VM following their instructions. I recommend using Ubuntu 20.04 LTS for the VM image.
Next, you'll want to create a service unit file for systemd. Systemd is the thing that runs on linux that manages startup processes. A Unit file will look something like this:
[Unit]
Description=Readings API Service
After=network.target
[Service]
EnvironmentFile=/etc/environment
Type=simple
User=app
WorkingDirectory=/home/app/deploy/packages/api
ExecStart=/usr/local/bin/node /home/app/deploy/packages/api/server.js
Restart=on-failure
[Install]
WantedBy=multi-user.target
In the above, I've created a user named "app" on the linux system, and created a folder named "deploy" in that user's home directory. I'm telling systemd to start that program when the computer starts, and to restart it if there's an error and it accidentally crashes.
It's going to take a bit of research and studying to understand all this and how it works, but hopefully this will get you started.
Related
Here's a weird one. My application(MFC, really out one) relies on a service(C++). Both app and service are my coding. And I found if I shutdown my PC while app running and power-on, the app will be ran by system. And it doesn't work well with my service.
To be more detailed, my app and service communicate through NamedPipe, so if the app ran by system, it could go wrong.
Which already has been confirmed is that if I turned off 'fast startup' in power option and my app won't run after a shutdown then power-on action any more.
My app won't run with 'restart' exactly match the description of
system option
I promised that I didn't add any 'let my app run by fast startup' that kind of code.
I'm really confusing right now and there're few articles about Windows Fast Startup mechanism. I did found an article from MSDN about fast-startup boot and cold boot. But it's all about drivers, not Win32 desktop apps.
Here's the link:
https://learn.microsoft.com/en-us/windows-hardware/drivers/kernel/distinguishing-fast-startup-from-wake-from-hibernation
Could anyone please help?
No code for now.
I don't want my app ran by system automatically.
(btw, in common sense, we should initially code for that, but
I am playing with node.js and angular for first time. I use shared server hosting space. I am trying to get some node.js tests running.
CPanel seem to provide interface to deploy node applications. Example:
application url: myurl.com
application root: node-hello-world
application startup file: app.js
This seems to create directory and some artifacts in
/home/myurl/nodevenv/node-hello-world/6/bin
I have (limited?) shell access through Cpanel emulation, however I get error on source command.
source activate
got error: error: jailshell: fork: Cannot allocate memory
Does this mean node.js is installed and ready to run? Do I have to upload project as well? Where to? Trying to find more info on process of deploying to this type of server if possible.
sorry for nooby question.
Googling your error message, I came across this thread -- which admittedly is very old, but it's from cPanel and has the following comment from an administrator at the time:
Jailshell is a constrained environment by design. It is not meant to be a replacement for a full-featured, unrestricted, shell environment, such as is provided by Bash. If your user's need such full-featured environments then perhaps they need full shell access, or another method whereby they can accomplish their goal.
That answer was given in 2006 (yes, 13 years ago) but I have to imagine the spirit of that response is still true.
To be perfectly honest, I'd be afraid to use any shared hosting provider that would give you more than very limited shell to use -- it opens the door to many security vulnerabilities, and if multiple customers are in the same runtime (i.e. shared hosting) it could be catastrophic. Maybe your host does allow this, or maybe what you're describing isn't actually the same thing I'm referring to... you didn't offer a lot of details on this point.
Back to your question: Does this mean node.js is installed and ready to run? Do I have to upload project as well? Where to?
If I had to guess, Node probably isn't installed (it isn't in most shared hosting providers) -- but I can't say for sure based on the information you provided. My recommendation would be to call their customer support. Or pay for a dedicated hosting account where you get root access. Or just use something like Heroku.
I'm moving my Three.js app and its customized node.js environment, which I've been running on my local machine to Google Cloud. I want to test things out there, and hopefully soon get some early alpha testing going with other people.
I'm not sure which is the wiser way to go... to upload the repo I've been running locally as-is onto a VM which users would then access via the VM's external IP until I get a good name to call this app... or merge my local node.js environment with what's available via the Google App Engine and run it on GAE.
Issues I'm running into with the linux VM approach... I'm not sure how to do the equivalent on the VM of what I've been doing locally. In Windows Powershell I cd into the app directory and then enter node index.js. I'm assuming by this method of deployment that I can get the app running as soon as the browser hits the external IP. I should mention too that the app will allow users to save content as well as upload images, and eventually, 3D models as well as json datasets.
Issues I'm running into with the App Engine approach: it looks like I only have access to a linux-based command line, and have to install all the node.js modules manually. Meanwhile I have a bunch of files to upload, both the server-side node files and all the frontend stuff. I don't see where to upload those files, and ultimately what I'd like to do is have access to a visual, editable file-tree interface, as I have in Windows and FileZilla, so I can swap files in and out, etc. Alternatively I suppose I could import a repo from Github? Github would be fine as long as I can visually see what's happening. Is there a visual interface for file structure available in GAE somewhere? Am I missing something?
I went through the GAE "Hello World" tutorial and that worked fine, but was left scratching my head afterward regarding how to actually see and edit the guts of the tutorial app, or even where to look for the files.
So first off, I want to determine what's the better approach, and then if possible, determine how to make the experience of getting my app up there and running a more visual, user-friendly experience.
Thanks.
There are many things to consider when choosing how to run an app, but my instinct for your use case is to simply use a VM on GCE. The most compelling reason for this is that it's the most similar thing to what you have now. You can SSH into the machine and run nohup node index.js & (or node index.js inside tmux/screen if you prefer) and it will start the app and not stop it when you log out of SSH. You can use SCP / SFTP with whatever GUI client you want to upload files. You don't have to learn anything new! If you wanted to, you could even use a Windows VM (although I think you have to pay a little more than for a comparable Linux VM due to the licensing fees).
That said, the other way is arguably more "correct" by modern development standards, but it will involve a lot more learning that will prevent you from getting your app running somewhere other than your laptop in the short term:
First, you'll need to learn about Docker and stateless containers, which is basically what your app runs inside of on AppEngine.
Next, you'll need to learn how to hook up a separate stateful service (database, file server, ...) to your app's container so you can store your files, etc. in it, and then probably rewrite your app somewhat to use it to store stuff.
Next, you'll probably want some way to automatically deploy this from code instead of manually doing it, which gets you into build systems, package managers, artifact storage, continuous integration systems, and on and on and on.
This latter path is certainly what you should choose for a long-running production service if you work with a big team of developers -- but that doesn't mean that it's necessarily the right path for your project today. If you don't care about scaling up automatically, load balancing between nodes, redundant copies of your app running in different regions in case there's a natural disaster, etc., then go with the easy way for now, and you can learn new ways to improve the service when they're actually needed.
I have not used Docker before at all, but I have a flask app running on an Azure server right now which I would like the mostly replicate to another server.
Ubuntu 16.10
Anaconda for my Python environments
A few systemd files to configure nginx and uwsgi
My goal is to start fresh without having to do a fresh install of the OS (I do not have the ability to do this) on my current server. I have a few issues with environments and multiple Python versions which I would like to escape from.
I would then like to take this set up and send it over to another server which is completely fresh (a brand new Azure instance which hasn't been touched yet). Is this possible with Docker?
To make things clear, Docker is not a technolgy to migrate applications from one server to another. Docker is a "vitualization" technology which allows you to isolate applications when they are running. Once you have this isolation, the Docker containers can be migrated to any server having just Docker installed. Thus you releive yourself from issues like "It works on this machine, but it doesn't work on that".
In order to do that, you need first to Dockerize your application. Your requirements are very common, and there are many samples online of how to containarize such applications.
However, you need first to learn about Docker to get started (which need a couple of hours/days). You can start learning about Docker here. Once you have your application dockerized and working on one machine, moving it to another server is a piece of cake.
I am a node.js developer. I use Amazon ec2 to deploy my node.js apps.
I want to have my node.js service running permanently - restarted if it fails for any reason.
I came across 2 tools . Forever and Upstart
Is there any advantages of using one over the other ?
Is there any other tool which is better ?
Upstart is a system service controller, similar to SysV Init and will start/stop/restart essentially any service registered for it, Node.js-based or not, and it will also automatically start services on system start for you. But Upstart is essentially specific to Ubuntu, and Upstart-specific services won't run on other Linux distros.
Upstart has a SysV Init compatibility layer that you could target,instead, to maintain as broad of a compatibility layer as possible.
Forever is a Node.js application that monitors and restarts other Node.js applications as needed, and as defined by its configuration JSON. Lots of options and fine-grained control over your service without the effort that would be needed to duplicate it in a custom SysV Init script. However, Forever isn't a system service, so if the server is restarted, you'll have to manually start your forever scripts again.
Beyond that, if all you need is something that will restart your script if/when it crashes, and you don't care about it starting automatically on system start, all you need is a bash script as simple as:
#!/bin/bash
while true
do
node ./myScript.js
done
Just to correct a misleading statement in the accepted answer...it is not true that upstart is an Ubuntu-only technology. See:
https://serverfault.com/questions/291546/centos-6-and-upstart
http://searchenterpriselinux.techtarget.com/tip/RHEL-6-ditches-System-V-init-for-Upstart-What-Linux-admins-need-to-know
http://en.wikipedia.org/wiki/Upstart#Adoption
With that, I think it is a much more compelling solution.