Modules Guide

Modules are the best way to organize your services in godi. They group related functionality, make dependencies explicit, and enable easy testing.

Why Use Modules?

Even for small apps, modules keep your code organized:

// Without modules - messy main function
func main() {
    collection := godi.NewCollection()
    collection.AddSingleton(NewDatabase)
    collection.AddSingleton(NewLogger)
    collection.AddSingleton(NewConfig)
    collection.AddSingleton(NewCache)
    collection.AddScoped(NewUserRepository)
    collection.AddScoped(NewUserService)
    collection.AddScoped(NewAuthService)
    // ... 20 more lines
}

// With modules - clean and organized
func main() {
    collection := godi.NewCollection()
    collection.AddModules(infrastructure.Module)
    collection.AddModules(repository.Module)
    collection.AddModules(service.Module)
}

Basic Module

Start simple:

// repository/module.go
package repository

import "github.com/junioryono/godi/v4"

var Module = godi.NewModule("repository",
    godi.AddScoped(NewUserRepository),
    godi.AddScoped(NewMatchRepository),
    godi.AddScoped(NewTeamRepository),
)

Use it:

// main.go
import "myapp/repository"

func main() {
    collection := godi.NewCollection()
    collection.AddModules(repository.Module)

    provider, _ := collection.Build()
    // ...
}

Module Dependencies

Modules can include other modules:

// core/module.go - Basic infrastructure
var CoreModule = godi.NewModule("core",
    godi.AddSingleton(NewConfig),
    godi.AddSingleton(NewLogger),
)

// database/module.go - Database services
var DatabaseModule = godi.NewModule("database",
    CoreModule,  // Depends on core
    godi.AddSingleton(NewDatabaseConnection),
    godi.AddScoped(NewTransaction),
)

// user/module.go - User features
var UserModule = godi.NewModule("user",
    DatabaseModule,  // Depends on database (which includes core)
    godi.AddScoped(NewUserRepository),
    godi.AddScoped(NewUserService),
)

// app/module.go - Complete application
var AppModule = godi.NewModule("app",
    UserModule,
    AuthModule,
    // All dependencies are included automatically
)