As software applications become more complex, developers need to find ways to ensure that their code remains scalable, portable, and maintainable. The 12 factor app is a methodology for building modern, cloud-native applications that adhere to a set of principles designed to make them more robust and easy to deploy.
The 12 factor app was first introduced in 2011 by engineers at Heroku, a cloud platform provider. Since then, it has become a widely recognized standard for building cloud-based applications. Here are the 12 factors:
- Codebase: Each application should have a single codebase tracked in version control. This allows developers to collaborate on changes and ensures that each deployment is based on a consistent codebase.
- Dependencies: Applications should explicitly declare and isolate their dependencies. This means using package managers and dependency manifests to ensure that each deployment has a consistent set of dependencies.
- Configuration: Applications should store configuration in the environment. This allows developers to change settings without having to modify the code or rebuild the application.
- Backing services: Applications should treat backing services (databases, caches, message brokers, etc.) as attached resources that can be attached and detached at runtime. This enables greater flexibility in deployment and scaling.
- Build, release, run: The process of building, releasing, and running an application should be separated. This allows for greater control over each stage of the deployment process.
- Processes: Applications should be designed to run as stateless processes. This means that any data that needs to be persisted should be stored in a stateful backing service.
- Port binding: Applications should be self-contained and bind to a port on the host environment. This allows them to be easily deployed and scaled.
- Concurrency: Applications should be designed to scale horizontally. This means that multiple instances of the application can run simultaneously to handle increased load.
- Disposability: Applications should be designed to start up and shut down quickly. This enables faster deployments and easier scaling.
- Dev/prod parity: The development, staging, and production environments should be as similar as possible. This helps to catch issues early and reduces the risk of unexpected behavior in production.
- Logs: Applications should generate logs as event streams. This enables easier debugging and analysis of application behavior.
- Admin processes: Administrative tasks should be run as one-off processes. This ensures that the application remains focused on its core functionality.
Adopting the 12 factor app methodology can provide significant benefits for application development. By designing applications to be cloud-native and scalable, developers can reduce deployment time and increase reliability. Furthermore, the 12 factor app provides a framework for developing applications that can be easily maintained and updated over time.
