Variables will show you how to use NGINX predefined variables as well as how to configure and use your own custom variables for a variety of use cases including logging, conditional proxying, dynamic black/whitelisting and the like.
Variables starts with a discussion of common use cases for variables. You'll then explore core HTTP module variables, special variables, and request variables and their uses. You'll look at variables in a common use case – forcing http traffic to https. You'll identify variables useful to debugging connections. Finally, you'll explore setting your own variables and understand variable scope in NGINX. This module has hands-on labs.