Stage 3 · Build

Production-Ready Services

12-Factor Services

Apply 12-factor principles for config, logs, disposability, backing services, and build-release-run.

7 min readBuilding Backend ApplicationsBuild

What Is 12-Factor

The 12-Factor App is a methodology for building modern, scalable SaaS applications. It covers code organization, dependencies, configuration, logs, and deployment. Following these principles makes your services portable and maintainable.

Codebase

One codebase tracked in version control, many deploys. Never mix code for multiple services in one repository. Each service has its own repo. Shared code is extracted into libraries.

Dependencies

Goexplicit-dependency-declaration.go

11 linesLn 1, Col 1Go

All dependencies are declared in go.mod. Go modules ensure reproducible builds. Never rely on system-installed packages. The build should work from a clean checkout.

Config

Store configuration in environment variables. Never in code. This includes database URLs, API keys, feature flags, and port numbers. Different environments get different configs without code changes.

Go12-factor-config-pattern.go

7 linesLn 1, Col 1Go

Config lives in environment variables, not in config files committed to git. This makes it easy to deploy the same code to dev, staging, and production.

Backing Services

Treat backing services (databases, caches, queues) as attached resources. Connect via URL. If the database moves from local to AWS RDS, change the URL, not the code.

Goresource-attachment-via-url.go

11 linesLn 1, Col 1Go

Every backing service connects via a URL from the environment. The code does not know or care whether the database is local or in the cloud. This is portability.

Disposability

Services must be disposable — fast to start up and graceful to shut down. This enables rapid scaling, deployments, and recovery from crashes.

Fast startup: Bind to ports and connect to backing services in under 1 second.
Graceful shutdown: Handle SIGTERM, drain connections, release resources.
Robust against sudden death: Use process managers and health checks.
Idempotent operations: Safe to restart mid-request without data corruption.

Gofast-startup-pattern.go

17 linesLn 1, Col 1Go

Measure startup time. Aim for under 1 second. If startup is slow, check database connections, DNS resolution, and initialization code.

Build, release, run

Separate build (compile binary), release (attach config), and run (start process). This ensures the same binary runs in every environment. Config is attached at runtime, not compile time.

Mark this lesson complete to store local progress and unlock a cleaner resume path the next time you visit.

Stage 3 · Build

Production-Ready Services

12-Factor Services

Apply 12-factor principles for config, logs, disposability, backing services, and build-release-run.

7 min readBuilding Backend ApplicationsBuild

What Is 12-Factor

Codebase

One codebase tracked in version control, many deploys. Never mix code for multiple services in one repository. Each service has its own repo. Shared code is extracted into libraries.

Dependencies

Goexplicit-dependency-declaration.go

11 linesLn 1, Col 1Go

All dependencies are declared in go.mod. Go modules ensure reproducible builds. Never rely on system-installed packages. The build should work from a clean checkout.

Config

Store configuration in environment variables. Never in code. This includes database URLs, API keys, feature flags, and port numbers. Different environments get different configs without code changes.

Go12-factor-config-pattern.go

7 linesLn 1, Col 1Go

Config lives in environment variables, not in config files committed to git. This makes it easy to deploy the same code to dev, staging, and production.

Backing Services

Treat backing services (databases, caches, queues) as attached resources. Connect via URL. If the database moves from local to AWS RDS, change the URL, not the code.

Goresource-attachment-via-url.go

11 linesLn 1, Col 1Go

Every backing service connects via a URL from the environment. The code does not know or care whether the database is local or in the cloud. This is portability.

Disposability

Services must be disposable — fast to start up and graceful to shut down. This enables rapid scaling, deployments, and recovery from crashes.

Fast startup: Bind to ports and connect to backing services in under 1 second.
Graceful shutdown: Handle SIGTERM, drain connections, release resources.
Robust against sudden death: Use process managers and health checks.
Idempotent operations: Safe to restart mid-request without data corruption.

Gofast-startup-pattern.go

17 linesLn 1, Col 1Go

Measure startup time. Aim for under 1 second. If startup is slow, check database connections, DNS resolution, and initialization code.

Build, release, run

Separate build (compile binary), release (attach config), and run (start process). This ensures the same binary runs in every environment. Config is attached at runtime, not compile time.

Mark this lesson complete to store local progress and unlock a cleaner resume path the next time you visit.