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Day One: Python for Platform Engineers

You know your way around a terminal. You've written bash scripts. You understand what a return code means, why you check $?, and why you don't run things as root unless you have to.

What you don't have — yet — is Python that's useful in your actual work. Not tutorial Python. Not "write a number-guessing game" Python. Python that solves the specific problems that come up when you're managing platforms and deployments.

That's what Day One is.

Who This Is For

Day One assumes you:

  • Work in platform engineering, SRE, infrastructure, or DevOps
  • Know bash well enough to write scripts that do real work
  • Have a specific problem to solve, not a general interest in "learning Python"

Day One does not assume you've written Python before. It does assume you don't need basic programming explained to you — you already know what a loop is, what a function is, what an exit code means.

What You'll Be Able to Do

By the end of Day One, you'll be able to handle these situations with Python:

Situation Article
You want to avoid breaking your system Python The Clean Setup
API needs to recover before traffic can cut back Is It Still Up?
Something broke in production, you have a giant log file What Just Broke?
You need to verify running config against expected Did the Config Change?
You need to run a check across your whole fleet Run This Everywhere
Your bash deploy script has gotten unmanageable My Bash Script Is Getting Out of Hand

Why Not Just Use Bash?

Short answer: use bash until you can't. Why Python (Not Just Bash) covers the decision framework in detail. The quick version:

  • Stay in bash for one-liners, pipelines, and glue between commands
  • Reach for Python when you need to do something with the output — count it, compare it, report on it, loop over a list and handle failures per-item

The articles in Day One are all situations where bash starts to cost you more than Python does.

The Articles

Work through these in order, or jump to the scenario you're facing right now:

  1. The Clean Setup — Setting up your Python environment correctly
  2. Why Python (Not Just Bash) — When to reach for Python instead of staying in bash
  3. Is It Still Up? — Polling a health endpoint during a redeploy
  4. What Just Broke? — Parsing a log file to find and understand errors
  5. Did the Config Change? — Comparing running config against expected
  6. Run This Everywhere — Checking a condition across a fleet of servers or services
  7. My Bash Script Is Getting Out of Hand — Wrapping shell commands in Python when bash gets unwieldy
  8. The "Don't Do This" Guide — Security and safety rules for production automation

One Rule Before You Start

Automation magnifies mistakes. A bash one-liner that goes wrong affects one run. A Python loop that goes wrong can affect 50 servers before you catch it.

Always test on one before you run on all. Always build a --dry-run flag before you build the real thing.

Start with Why Python (Not Just Bash) for the framework, or jump straight to whichever scenario you're dealing with today.