golang-structs-interfaces

Design small Go interfaces by limiting them to 1-3 methods to promote decoupling. You should define interfaces where they are consumed rather than where they are implemented, ensuring constructors accept interfaces but return concrete struct types.

Avoid premature interfaces in Go by starting with concrete struct implementations. You should extract interfaces only when multiple implementations are actually needed, preventing unnecessary abstraction and maintaining code readability.

The best way to handle dependency injection in Go is to accept interfaces in your constructors while returning concrete struct types. This approach enforces clean dependency injection and improves testability without coupling packages.

Use struct embedding when you need to promote an API to the outer struct, and use named fields for internal composition. This distinction enforces clear API boundaries and consistent receiver usage across your Go services.

Defining Go interfaces in the consumer package prevents bloated and brittle dependencies. It ensures the consumer only declares the methods it actually needs, promoting decoupling and compile-time checks across services.

Compile-time checks in Go verify that concrete structs satisfy consumed interfaces at build time. By keeping interfaces small and returning concrete types from constructors, you ensure strict dependency injection and embedding decisions are validated early.