nix-amer/internal/pkg/loader.go

package pkg

import (
	"errors"
)

// ErrUnknownManager is raised when the asked manager does not exist
var ErrUnknownManager = errors.New("unknown package manager")

// ErrNotInstalled is raised when the candidate package manager is not installed
// on the host system (use command-line -dry-run to avoid execution errors and just
// check your buildfile syntax)
var ErrNotInstalled = errors.New("no candidate installed")

// Load a specific package-manager by its name
func Load(_manager string) (PackageManager, error) {

	// 1. create manager (fail if unknown)
	var manager PackageManager
	switch _manager {
	case "apt-get":
		manager = new(aptGet)
	case "apk":
		manager = new(apk)
	case "eopkg":
		manager = new(eopkg)
	case "pacman":
		manager = new(pacman)
	case "dnf":
		manager = new(dnf)
	case "yum":
		manager = new(yum)
	default:
		return nil, ErrUnknownManager
	}

	// 2. fail if not installed
	// if exec.Command("which", manager.Name()).Run() != nil {
	// 	return nil, ErrNotInstalled
	// }

	return manager, nil

}