docs: add 12/15factor apps

radar/2024-06-01/12-factor-apps.md

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+---
+title:      "12 / 15 factor apps"
+ring:       adopt
+quadrant:   methods-and-patterns
+tags:       [architecture]
+---
+
+The [12-factor app](https://12factor.net/de/) methodology, originally developed by Heroku, provides a comprehensive set of best practices for building cloud-native applications. This methodology emphasizes creating applications that are easy to manage, scalable, and portable across different environments. The [15-factor model](https://developer.ibm.com/articles/15-factor-applications/) extends this framework to address additional concerns relevant in modern cloud-native development.
+
+### Core Principles of 12-Factor Apps
+
+1) **Codebase**: Maintain a single codebase tracked in version control, with multiple deployments.
+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.
+7) **Port Binding**: Export services via port binding.
+8) **Concurrency**: Scale out via the process model.
+9) **Disposability**: Maximize robustness with fast startup and graceful shutdown.
+10) **Dev/Prod Parity**: Keep development, staging, and production as similar as possible.
+11) **Logs**: Treat logs as event streams.
+12) **Admin Processes**: Run admin/management tasks as one-off processes.
+
+### Extending to 15 Factors
+
+The 15-factor model builds upon the original principles by adding:
+
+13) **API First**: Design APIs first to ensure interoperability and future-proofing.
+14) **Telemetry**: Implement robust telemetry for monitoring and diagnostics.
+15) **Authentication and Authorization**: Incorporate strong, centralized authentication and authorization mechanisms.
+
+
+### Relevance
+
+For us this rather old pattern is still very relevant and many methods, patterns and practices on our radar are related and enable these pattern in their core. To name a few [Kubernetes](/platforms-and-aoe-services/kubernetes/), [Prometheus](/platforms-and-aoe-services/prometheus/), [Self-Service Infrastructure](/platforms-and-aoe-services/self-service-infrastructure/) or the [API-First Design Approach](/methods-and-patterns/api-first-design-approach/) are very related, others like [Shared Responsibility Models](/methods-and-patterns/shared-responsibility/) are easier to implement based on this pattern.