doge

Type-safe DI container for Go 1.18+. Global registry, generic API, no code generation.

One file, 75 lines, zero dependencies.

Install

go get codeberg.org/kran/doge

API

func Set[T any](comp T, scopes ...string)        // Register. Panics if already registered.
func Get[T any](scopes ...string) T              // Retrieve. Panics if not found.
func TryGet[T any](keys ...string) (T, bool)     // Retrieve. Returns (zero, false) if not found.
func Reset()                                      // Clear all. For testing.

Usage

// Register
db := connectDB()
doge.Set[*sql.DB](db)

// Retrieve
db := doge.Get[*sql.DB]()

// Safe retrieve
db, ok := doge.TryGet[*sql.DB]()

Interfaces

type UserRepo interface { Find(id int64) (*User, error) }

doge.Set[UserRepo](&PostgresUserRepo{db: db})

repo := doge.Get[UserRepo]()

Keyed instances

Multiple instances of the same type, distinguished by key:

doge.Set[*sql.DB](primaryDB, "primary")
doge.Set[*sql.DB](replicaDB, "replica")

primary := doge.Get[*sql.DB]("primary")
replica := doge.Get[*sql.DB]("replica")

Testing

func TestSomething(t *testing.T) {
    doge.Reset()
    doge.Set[UserRepo](&MockUserRepo{})
    // ...
}

Behavior

• Set the same type (and key) twice: panic.
• Get an unregistered type: panic.
• TryGet an unregistered type: returns zero value and false.
• All operations are goroutine-safe (sync.RWMutex).
• Component names are derived from reflect.Type: package path + type name.

What it does not do

• Scopes or lifecycles
• Auto-wiring or constructor injection
• Lazy initialization
• Dependency graphs or cycle detection