Using Environment Variables in your Code

Introduction

What is an environment variable?
Setting environment variables
Using enviroment variables in Java
Using enviroment variables in Python
Best practices

Environment variables

Environment variables…

Setting environment variables:

There are a few ways to set an environent variable:

Adding to bash file: Edit your .zshrc file (or .bashrc for bash shell) and add the key/value pair as follows:

#list of environment variables
DB_URL=jdbc:mysql://localhost:3306/mydatabase
DB_USER=mydbuser
DB_PASSWORD=GimmeTheData2030

Using environment variables in Java:

public class AccessEnvironementVars {
    public static void main(String[] args) {
        String dbUrl = System.getenv("DB_URL");
        
        if (dbUrl != null) {
            System.out.println("Database URL: " + dbUrl);
        } else {
            System.out.println("Environment variable DB_URL not found.");
        }
    }
}

Using environment variables in Python:

To use environment variables in Python, you can leverage the os module:

Accessing an environment variable:

import os
# Get the value of the environment variable named 'MY_VARIABLE'
my_var = os.environ.get('MY_VARIABLE')

if my_var:
    print(my_var)
else:
    print("Environment variable 'MY_VARIABLE' not found.")

Output:

Environment variable 'MY_VARIABLE' not found.

Setting an environment variable:

import os

# Set the value of the environment variable 'MY_VARIABLE'
os.environ['MY_VARIABLE'] = 'Hello, World!'

# Access the newly set variable
print(os.environ.get('MY_VARIABLE'))

Output:

Hello, World!

Important considerations:

Security:

Avoid hardcoding sensitive information like API keys or database credentials in your code. Instead, store them as environment variables. .env files:
Consider using a library like python-dotenv to manage environment variables from a .env file. This makes it easier to manage and share environment variables across projects.
Data
Storage
Central Point
Manipulating data
Relation databases

Process isolation:

Environment variables are specific to each process. If you set an environment variable in one Python script, it won’t be automatically available in another script.

Best Practices For Using Environment Variables in Python

Always add . env files to . … While defining variables use descriptive, all UPPERCASE names.

Good:
```
 DEBUG=True 
 LOGGING_VERBOSITY=3
```
Bad:
```
 debug=True 
 LV=3
```

Best Practices For Using Environment Variables in Java

Good:
```
 DEBUG=True 
 LOGGING_VERBOSITY=3
```
Bad:
```
 debug=True 
 LV=3
```