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
pkg/observability/package.go
cmd/main.go

package stores

var Package = do.Package(
    do.Lazy(NewPostgreSQLConnectionService),
    do.Lazy(NewUserRepository),
    do.Lazy(NewArticleRepository),
)

package observability

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

package main

import (
    "github.com/foo/bar/pkg/stores"
    "github.com/foo/bar/pkg/observability"
    "github.com/foo/bar/pkg/handlers"
)

func main() {
    injector := do.New()
    stores.Package(injector)
    observability.Package(injector)

    // could be replaced by:
    // injector := do.New(
    //     stores.Package,
    //     observability.Package,
    // )

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

Play: https://go.dev/play/p/kmf8aOVyj96

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)

Registration​

Registration