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Package loading

Package loading groups multiple service registrations.

Registration​

The services can be assembled into a package, and then, exported all at once.

// pkg/stores/package.go

var Package = do.Package(
    do.Lazy(NewPostgresqlConnectionService),
    do.Lazy(NewUserRepository),
    do.Lazy(NewArticleRepository),
)
// pkg/observability/package.go

var Package = do.Package(
    do.Eager(slog.New(slog.NewTextHandler(os.Stdout, nil))),
    do.EagerNamed("prometheus.collector", DefaultMetricCollector),
)
// cmd/main.go

import (
    "example/pkg/stores"
    "example/pkg/observability"
    "example/pkg/handlers"
)

func main() {
    injector := do.New(stores.Package, observability.Package)
    // 
    // equivalent to:
    // 
    // injector := do.New()
    // stores.Package(injector)
    // observability.Package(injector)

    // ...

    // optional scope:
    scope := injector.Scope("handlers", handlers.Package)

    // ...
}

The traditional vocab can be translated for package registration:

  • Provide[T](Injector, Provider[T]) -> Lazy(Provider[T])
  • ProvideNamed[T](Injector, string, Provider[T]) -> LazyNamed(string, Provider[T])
  • ProvideValue(Injector, T) -> Eager(T)
  • ProvideNamedValue[T](Injector, string, T) -> EagerNamed(string, T)
  • ProvideTransient[T](Injector, Provider[T]) -> Transient(Provider[T])
  • ProvideNamedTransient[T](Injector, string, Provider[T]) -> TransientNamed(string, Provider[T])
  • As[Initial, Alias](Injector) -> Bind[Initial, Alias]()
  • AsNamed[Initial, Alias](Injector, string, string) -> BindNamed[Initial, Alias](string, string)