1package settings
 2
 3import (
 4	"context"
 5	"fmt"
 6	"sync"
 7)
 8
 9var (
10	registry = map[string]Constructor{}
11	mtx      sync.RWMutex
12
13	// ErrNotFound is returned when a setting is not found.
14	ErrNotFound = fmt.Errorf("setting not found")
15)
16
17// Constructor is a function that returns a new setting.
18type Constructor func(ctx context.Context) (Settings, error)
19
20// Register registers a setting.
21func Register(name string, fn Constructor) {
22	mtx.Lock()
23	defer mtx.Unlock()
24
25	registry[name] = fn
26}
27
28// New returns a new setting.
29func New(ctx context.Context, name string) (Settings, error) {
30	mtx.RLock()
31	fn, ok := registry[name]
32	mtx.RUnlock()
33
34	if !ok {
35		return nil, ErrNotFound
36	}
37
38	return fn(ctx)
39}
40
41// List returns a list of registered settings.
42func List() []string {
43	mtx.Lock()
44	defer mtx.Unlock()
45	settings := make([]string, 0)
46	for name := range registry {
47		settings = append(settings, name)
48	}
49	return settings
50}