python-devops-automation

Python DevOps Automation

Automation patterns for infrastructure, cloud, and operational tasks.

Core Principles

1. Idempotent operations - Safe to run multiple times
2. Error handling first - Anticipate failures
3. Logging over print - Structured, searchable logs
4. Configuration external - Environment variables, config files

CLI Development with Click

Use click for command-line tools

import click

@click.command()
@click.option('--count', default=1, help='Number of times to run')
@click.option('--verbose', is_flag=True, help='Verbose output')
@click.argument('name')
def greet(count, verbose, name):
    """Simple CLI tool."""
    for _ in range(count):
        if verbose:
            click.echo(f'Greeting: Hello {name}!')
        else:
            click.echo(f'Hello {name}!')

if __name__ == '__main__':
    greet()

See cli-patterns.md for:

• Command groups
• Progress bars
• File handling
• Click vs Typer

AWS Automation with Boto3

Use boto3 for AWS operations

import boto3

# S3 operations
s3 = boto3.client('s3')
s3.upload_file('local.txt', 'bucket-name', 'remote.txt')

# EC2 operations
ec2 = boto3.resource('ec2')
instances = ec2.instances.filter(
    Filters=[{'Name': 'tag:Environment', 'Values': ['production']}]
)

See boto3-patterns.md for:

• Resource vs client
• Pagination
• Error handling
• Credential management

Subprocess Management

Use subprocess for external commands

import subprocess

# Run command, capture output
result = subprocess.run(
    ['ls', '-la'],
    capture_output=True,
    text=True,
    check=True
)
print(result.stdout)

# Stream output in real-time
process = subprocess.Popen(
    ['long-running-command'],
    stdout=subprocess.PIPE,
    stderr=subprocess.PIPE,
    text=True
)

for line in process.stdout:
    print(line, end='')

returncode = process.wait()

See subprocess-patterns.md for:

• Error handling
• Timeouts
• Shell=True dangers
• Environment variables