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Dependency Injection ​

Flamigo embraces Dependency Injection (DI) as a core design principle to promote loose coupling and enhance testability across your application. Instead of hard-coding dependencies directly inside your services or domains, Flamigo encourages the use of well-defined interfaces and provides a mechanism to inject concrete implementations where needed.

All dependency resolution is handled at runtime, enabling you to easily substitute mocks, switch implementations, or reorganize your architecture without refactoring core business logic. By decoupling components from their dependencies, Flamigo helps you write more maintainable, modular, and scalable code.

Dependency Manager ​

Flamigo ships with a simple but powerful built-in Dependency Manager, located in the injection package. It handles wiring and resolving dependencies for your application at runtime.

Getting Started ​

To create a new injecter instance:

go
package main

import (
  "github.com/amberbyte/flamigo/injection"
)

func main() {
  inj := injection.NewDependencyInjecter()
}

DANGER

Only add and inject dependencies during your apps startup, never on demand during runtime as this may lead to unforseen problems and hard to track down runtime errors

Adding a Dependency ​

You can register a dependency using AddInjectable(i any) error:

go
package main

import (
  "github.com/amberbyte/flamigo/injection"
)

func main() {
  inj := injection.NewDependencyInjecter()
  myDep := &ExampleRepository{}

  if err := inj.AddInjectable(myDep); err != nil {
    panic(err)
  }
}

INFO

An error is returned if a dependency is already managed or conflicts with another injectable.

Injecting Dependencies ​

Dependencies can be dynamically injected by defining a function that takes them as parameters:

go
func createMyLogic(repo *ExampleRepository) error {
  // your logic here
  return nil
}

Then execute it through the injecter:

go
func main() {
  inj := injection.NewDependencyInjecter()
  inj.AddInjectable(&ExampleRepository{})

  if err := inj.Execute(createMyLogic); err != nil {
    panic(err)
  }
}

INFO

Interfaces are also supported — the Dependency Manager automatically matches the appropriate implementation if it satisfies the interface.

Execute returns an error if: ​

  • A required dependency cannot be resolved
  • The function returns an error
  • There’s ambiguity — i.e., multiple injectables satisfy the same interface