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 service registration:

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