如何仅通过命令行启动服务器并在虚拟机中运行？

Question

I wrote a server application in Python with Flask and now I would like to get it up and running on a virtual machine I have set up. Thus, I would really appreciate guidance in two areas.

1. How do I get a server setup so that it is perpetually running, and other computers can access it? The computers can be in the same network so I don't have to worry about a domain name or anything. I am just looking for multiple devices to be able to access it. I am currently able to run the server on my local machine and everything works just fine.

2. I have my virtual linux machine set up remotely, so I SSH into it and do everything from command line, but I am a bit lost as to how to do the aforementioned stuff from the command line.

Any guidance/help is much appreciated! The web-searching I have done hasn't pointed me in the right direction. I apologize if any of my terminology was off (if so, please feel free to correct me so I learn!). Thank you!

Answer 1

Use systemd on Ubuntu, /etc/systemd/system , for a simple setup (probably not ideal for a production setup though).

I do this sometimes for Python Flask app that I'm prototyping. First, put your application code in /opt/my-app . I usually just cd /opt and git clone a repo there. Then, create a file called /etc/systemd/system/my-app.service . In that file, add the following:

[Unit]
Description=My App daemon
After=network.target postgresql.service 
Wants=postgresql.service 

[Service]
EnvironmentFile=/etc/sysconfig/my-app
WorkingDirectory=/opt/my-app/ # <- this is where your app lives
User=root
Group=root
Type=simple
ExecStart=/usr/bin/python server.py # <- this starts your app
Restart=always
RestartSec=5s

[Install]
WantedBy=multi-user.target

Next, paste any environment variables you have into a file called /etc/sysconfig/my-app like:

DB_HOST=localhost
DB_USER=postgres 
DB_PASSWORD=postgres 
DB_NAME=postgres

Then you can do:

service my-app start
service my-app stop
service my-app restart

and then you can hit the app running on the servers IP and port (just like if you ran python app.py or python server.py . To check the logs for your daemon process, if it doesn't seem to work out, you can run:

journalctl -u my-app -e 

In production, I'm not sure this is the best setup, probably better to look into something like ngnix. But I do this for prototypes all the time and it's pretty great.