Retrieving Multiple Elements

These functions retrieve all registered elements that match the requested type. This requires DuckTypeElements config to be enabled in the injector configuration.

Key Points:

📦 Returns all matching implementations
🦆 Requires DuckTypeElements: true in injector config
🔍 Useful for plugin systems and service discovery

Prerequisites

Enable duck typing in the injector configuration:

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inj := remy.NewInjector(remy.Config{DuckTypeElements: true})

GetAll

GetAll retrieves all registered elements that match the requested type and returns an error if something goes wrong.

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package main

import (
	"log"

	"github.com/wrapped-owls/goremy-di/remy"
)

type Service interface {
	DoSomething()
}

func main() {
	// Returns all services that implement the Service interface
	services, err := remy.GetAll[Service](injector)
	if err != nil {
		log.Fatal(err)
	}

	for _, service := range services {
		service.DoSomething()
	}
}

MustGetAll

MustGetAll panics if an error occurs or if DuckTypeElements is not enabled.

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package main

import (
	"github.com/wrapped-owls/goremy-di/remy"
)

func main() {
	services := remy.MustGetAll[Service](injector)
	// Panics if DuckTypeElements is not enabled or if an error occurs
	for _, service := range services {
		service.DoSomething()
	}
}

MaybeGetAll

MaybeGetAll returns an empty slice if an error occurs, allowing graceful handling of missing dependencies.

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package main

import (
	"github.com/wrapped-owls/goremy-di/remy"
)

func main() {
	services := remy.MaybeGetAll[Service](injector)
	// Returns empty slice if error occurs or DuckTypeElements is not enabled
	for _, service := range services {
		service.DoSomething()
	}
}

Use Cases

Plugin Systems

When you have multiple implementations of the same interface:

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package main

import (
	"log"

	"github.com/wrapped-owls/goremy-di/remy"
)

type Plugin interface {
	Name() string
	Execute()
}

func main() {
	// Register multiple plugins
	remy.RegisterInstance(injector, &PluginA{})
	remy.RegisterInstance(injector, &PluginB{})
	remy.RegisterInstance(injector, &PluginC{})

	// Retrieve all plugins
	plugins := remy.MustGetAll[Plugin](injector)
	for _, plugin := range plugins {
		log.Printf("Executing plugin: %s", plugin.Name())
		plugin.Execute()
	}
}

Service Discovery

Discover all services that implement a specific interface:

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package main

import (
	"log"

	"github.com/wrapped-owls/goremy-di/remy"
)

type HealthCheckable interface {
	HealthCheck() error
}

func main() {
	// All registered health-checkable services
	healthServices := remy.MustGetAll[HealthCheckable](injector)
	for _, service := range healthServices {
		if err := service.HealthCheck(); err != nil {
			log.Printf("Health check failed: %v", err)
		}
	}
}

Important Notes
Ambiguity: If you need a specific implementation, use tags instead of GetAll
Empty Results: GetAll may return an empty slice if no matches are found (this is not an error)