12 Factor Applications (Pt 1)

Alex Axthelm

Introduction

Motivation

  • Developing and Deploying Apps can be difficult
  • The 12 Factor App methodology provides guidelines that ensure
    • clarity,
    • scalability,
    • maintainability
  • Benefits both developers and operations teams.

Why are 12 Factor Apps Important?

  • Consistency and predictability in application behavior.
  • Simplifies the development lifecycle.
  • Eases the process of deploying, scaling, and maintaining applications.
  • Promotes collaboration between development and operations (DevOps).

Best Practices

A lot of these concepts are things that are considered best practices, but collected together.

  • You are probably already do a bunch of these things
  • You may not know you do it (it just feels right)
  • You may not know why you do it (it just seems to work)
  • You may do it because you were told to (it isn’t broken)

Benefits for Developers

  • Clear guidelines for application structure and behavior.
  • Simplified onboarding and reduced cognitive load.
  • Easier debugging and local development.
  • Predictable dependencies and environments.

Benefits for DevOps/Operations

  • Streamlined deployment and automated management.
  • Improved reliability and faster issue resolution.
  • Easier monitoring and logging.

The 12 Factors (Brief Overview)

  1. Codebase: One codebase tracked in version control, many deploys.
  2. Dependencies: Explicitly declare and isolate dependencies.
  3. Config: Store configuration in the environment.
  4. Backing Services: Treat backing services as attached resources.
  5. Build, Release, Run: Strictly separate build and run stages.
  6. Processes: Execute the app as one or more stateless processes.

The 12 Factors (Brief Overview)

  1. Port Binding: Export services via port binding.
  2. Concurrency: Scale out via the process model.
  3. Disposability: Maximize robustness with fast startup and graceful shutdown.
  4. Dev/Prod Parity: Keep development, staging, and production similar.
  5. Logs: Treat logs as event streams.
  6. Admin Processes: Run admin tasks as one-off processes.

Examples of Common Pitfalls

  • Configuration hardcoded in source code.
  • Dependencies not clearly defined or versioned.
  • Stateful processes causing unpredictable behavior.
  • Significant differences between development and production environments.

Getting Started with 12 Factor Apps

  • Review your current projects against the 12 factors.
  • Incrementally adopt factors as you enhance or refactor projects.
  • Foster collaboration and awareness across development and operations teams.