Flask demo

Deployment

Run ./install.sh. It will:

• create a virtual environment in this folder, called locutus.venv. This is where all the dependencies will be installed
• install the dependencies from app/requirements.txt. Note that now this file contains linux requirements; conda interprets some system libraries as packages and will need them to be installed separately. See comments in the file for more details.
• install uwsgi. Most Python web applications expect HTTP requests in a certain format, WSGI. This is similar to CGI and FastCGI that were popular in the past, but works faster. Although flask contains a built-in HTTP server, it doesn't make use of threads and isn't considered secure; it is just a development server. In production, you offload this work to WSGI servers, which pack incoming socket data to understandable in-memory WSGI data strucures. uwsgi will create a unix socket lockutus.sock in this directory when active.
• create a service for uwsgi, so if/when it fails, system will restart the process automatically. Now you can start and stop the service with commands like sudo service locutus start or sudo service locutus stop.
• install nginx, if necessary. Most WSGI servers aren't good at handling network socket magic, like thousands of simultaneous, often slow, clients. So, on top of uwsgi server we set up a web server, which is good at it. As a bonus, nginx will also take care of serving static files, which it does a lot more efficiently than flask itself.

After this, the website should be operational