Applications need to be reliable, scalable and easy to maintain. Whether you are a startup building your first product or an enterprise want to scale your product globally, following the guidelines, methods, and best practices can significantly impact the outcome. The 12-Factor App Methodology is a set of best practices designed to help developers create modern applications. These methodologies were created by engineers at Heroku, these principles are now a guide for building softwares. Let’s explore each factor in detail and understand why it is important.
1. Codebase: One Codebase, Many Deployments
Every application should have a single code repository (i.e., GitHub or GitLab). Almost all applications has multiple environments like development, staging and production and the code for these environments should come from the same codebase. This make the application easier to manage and ensures that every team member works on the same version of the code.
2. Dependencies: Declare and Isolate
An application depends on various libraries and packages to work properly. The application should list all its dependencies in a file like requirements.txt for Python or package.json for JavaScript. This ensures that the application works the same way no matter where it is deployed.
3. Config: Store Configurations in the Environment
Applications mostly require configuration like database credentials, API keys and many more. Store these configurations in environment variables instead of hardcoding these settings into the application. This separates code from configuration and making it easier to change settings without touching the code.
4. Backing Services: Treat Them as Attached Resources
Services like databases, caches, message brokers, third party APIs and file storage are called backing services. These backing services should be treated as replaceable and plug-in-play. For example, if your application is using PostgreSQL, it should work even if the database is replaced or moved to another server, it should have minimal impact on your application.
5. Build, Release, Run: Separate the Stages
An application goes through the following three stages:
- Build: Prepare the code by compiling or packaging it.
- Release: Combine the build with configurations for a specific environment.
- Run: Execute the application in production.
By separating these stages, you can fix bugs or update configurations without rebuilding the entire app.
6. Processes: Stateless and Independent
Make sure that your application don’t store any data or remember anything from previous requests. Instead, use external tools like database or caches to save data. This approach makes your application easier to scale (you can add more instances without any issues).
7. Port Binding: Export Services via Ports
Applications should expose their functionality through a specific port. For example, a web application might use port 8080 to accept requests. This allows the application to run as a standalone service without needing an additional web server.
8. Concurrency: Scale Horizontally
Use multiple instances instead of running a single large instance of your application. For example, if you have 1000 users, you can run 5 instances of the application to handle them. This makes your application scale easier and ensures high availability.
9. Disposability: Handle Restarts Gracefully
Applications should run fast and shut down gracefully. This makes it easier to handle updates, crashes or scaling. For example, if a server goes down, your application should recover or restart gracefully without losing data or causing any other issues.
10. Dev/Prod Parity: Keep Environments Similar
Your development, staging and production environments should be as similar to the maximum extent. This minimizes the chances of bugs appearing in production that were not caught during testing. Tools like Docker can help replicate environments like production on your local machine.
11. Logs: Treat as Event Streams
Logs all the events happening in your application like user actions or exceptions. Send them to a central logging system (e.g, Logstash or Datadog) instead of saving logs directly in files. This makes it easier to analyze logs across all application instances.
12. Admin Processes: Run as One-Off Tasks
Sometimes you need to perform tasks like database migrations or cleanup. These admin tasks should be run as separate processes not as part of the application’s regular workflow. For example, you might run a one-time script to fix some data.
Why Follow the 12-Factor Principles?
- Scalability: Easily add more users or handle more traffic.
- Portability: Deploy your app on any cloud platform.
- Maintainability: Fix bugs and add features faster.
- Reliability: Handle failures gracefully.
The 12-Factor App principles provide a clear roadmap for building applications that are reliable and easy to scale. Whether you are developing a small project or a large system, these guidelines will simplify your work and make your application better. Start implementing these practices today and watch your applications perform like never before.