golang-dependency-injection

Dependency injection in Go is best implemented by wiring infrastructure, repositories, and services via manual constructor injection in the main function, then migrating to a DI library like google/wire or samber/do as the project grows to ensure testable architectures.

Choosing between google/wire, uber-go/dig, uber-go/fx, and samber/do requires comparing DI approaches across project sizes, evaluating code generation versus runtime reflection, and assessing lifecycle management needs for your specific microservices architecture.

You should use a dependency injection library instead of manual wiring when your Go project grows from a small service to a large microservices architecture, requiring automated lifecycle management and complex mockability for testing.

To avoid global state and init-time wiring in Go applications, structure your code using constructor injection within the main function, passing dependencies explicitly to achieve loosely coupled, testable components.

Dependency injection works well for large Go microservices by providing best-practice guidance for testable architectures, supporting complex constructor injection, lifecycle considerations, and scalable mockability across growing project sizes.