Day 97: Custom Modules in Python

Today, I learned how to create and use custom modules in Python — a major step toward building organized and reusable automation codebases for DevOps tasks.

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📦 What is a Module?

A module is simply a .py file containing functions, classes, or variables you want to reuse.
It allows code separation, organization, and reuse — just like how DevOps tools are broken into different services/components.

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📝 Step 1: Create a Module

File: devops_utils.py

def deploy_app(app_name, server):
    print(f"Deploying {app_name} to {server}...")

def restart_service(service):
    print(f"Restarting {service}...")

env = "production"

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⚙️ Step 2: Use the Module in Another Script

File: main.py

import devops_utils

print(f"Environment: {devops_utils.env}")
devops_utils.deploy_app("vprofile", "web01")
devops_utils.restart_service("nginx")

Output:

Environment: production
Deploying vprofile to web01...
Restarting nginx...

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⚙️ Step 3: Use from ... import ...

You can also import only what you need:

from devops_utils import deploy_app

deploy_app("inventory-service", "web02")

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📌 Why This Matters in DevOps

✅ You can group all your server management functions in one module.
✅ Create utility modules for logging, backups, deployments, and more.
✅ Makes scripts clean, reusable, and collaborative across teams.

This is how real-world DevOps teams build their automation toolkits in Python.

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💡 Key Takeaways

• Custom modules = reusable .py files

• Organize code into logical units

• Import modules across multiple scripts for automation