feat(store/valkey): add Redis(R) Sentinel support

Signed-off-by: Xe Iaso <me@xeiaso.net>

lib/store/valkey/factory.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/TecharoHQ/anubis/internal"
 	"github.com/TecharoHQ/anubis/lib/store"
 	valkey "github.com/redis/go-redis/v9"
 	"github.com/redis/go-redis/v9/maintnotifications"
@@ -16,26 +17,89 @@ func init() {
 	store.Register("valkey", Factory{})
 }
 
-// Errors kept as-is so other code/tests still pass.
 var (
 	ErrNoURL  = errors.New("valkey.Config: no URL defined")
 	ErrBadURL = errors.New("valkey.Config: URL is invalid")
+
+	// Sentinel validation errors
+	ErrSentinelMasterNameRequired = errors.New("valkey.Sentinel: masterName is required")
+	ErrSentinelAddrRequired       = errors.New("valkey.Sentinel: addr is required")
+	ErrSentinelPasswordRequired   = errors.New("valkey.Sentinel: password is required")
+	ErrSentinelAddrEmpty          = errors.New("valkey.Sentinel: addr cannot be empty")
 )
 
 // Config is what Anubis unmarshals from the "parameters" JSON.
 type Config struct {
 	URL     string `json:"url"`
 	Cluster bool   `json:"cluster,omitempty"`
+
+	Sentinel *Sentinel `json:"sentinel,omitempty"`
 }
 
 func (c Config) Valid() error {
-	if c.URL == "" {
-		return ErrNoURL
+	var errs []error
+
+	if c.URL == "" && c.Sentinel == nil {
+		errs = append(errs, ErrNoURL)
 	}
 
-	// Just validate that it's a valid Redis URL.
-	if _, err := valkey.ParseURL(c.URL); err != nil {
-		return fmt.Errorf("%w: %v", ErrBadURL, err)
+	// Validate URL only if provided
+	if c.URL != "" {
+		if _, err := valkey.ParseURL(c.URL); err != nil {
+			errs = append(errs, fmt.Errorf("%w: %v", ErrBadURL, err))
+		}
+	}
+
+	if c.Sentinel != nil {
+		if err := c.Sentinel.Valid(); err != nil {
+			errs = append(errs, err)
+		}
+	}
+
+	if len(errs) > 0 {
+		return errors.Join(errs...)
+	}
+
+	return nil
+}
+
+type Sentinel struct {
+	MasterName string                  `json:"masterName"`
+	Addr       internal.ListOr[string] `json:"addr"`
+	ClientName string                  `json:"clientName,omitempty"` // if not set, default to Anubis or anubis.ProductName.
+	Username   string                  `json:"username,omitempty"`   // if not set, ignored
+	Password   string                  `json:"password"`
+}
+
+func (s Sentinel) Valid() error {
+	var errs []error
+
+	if s.MasterName == "" {
+		errs = append(errs, ErrSentinelMasterNameRequired)
+	}
+
+	if len(s.Addr) == 0 {
+		errs = append(errs, ErrSentinelAddrRequired)
+	} else {
+		// Check if all addresses in the list are empty
+		allEmpty := true
+		for _, addr := range s.Addr {
+			if addr != "" {
+				allEmpty = false
+				break
+			}
+		}
+		if allEmpty {
+			errs = append(errs, ErrSentinelAddrEmpty)
+		}
+	}
+
+	if s.Password == "" {
+		errs = append(errs, ErrSentinelPasswordRequired)
+	}
+
+	if len(errs) > 0 {
+		return errors.Join(errs...)
 	}
 
 	return nil
@@ -68,14 +132,15 @@ func (Factory) Build(ctx context.Context, data json.RawMessage) (store.Interface
 		return nil, err
 	}
 
-	opts, err := valkey.ParseURL(cfg.URL)
-	if err != nil {
-		return nil, fmt.Errorf("valkey.Factory: %w", err)
-	}
-
 	var client redisClient
 
-	if cfg.Cluster {
+	switch {
+	case cfg.Cluster:
+		opts, err := valkey.ParseURL(cfg.URL)
+		if err != nil {
+			return nil, fmt.Errorf("valkey.Factory: %w", err)
+		}
+
 		// Cluster mode: use the parsed Addr as the seed node.
 		clusterOpts := &valkey.ClusterOptions{
 			Addrs: []string{opts.Addr},
@@ -86,7 +151,23 @@ func (Factory) Build(ctx context.Context, data json.RawMessage) (store.Interface
 			},
 		}
 		client = valkey.NewClusterClient(clusterOpts)
-	} else {
+	case cfg.Sentinel != nil:
+		opts := &valkey.FailoverOptions{
+			MasterName:       cfg.Sentinel.MasterName,
+			SentinelAddrs:    cfg.Sentinel.Addr,
+			SentinelUsername: cfg.Sentinel.Username,
+			SentinelPassword: cfg.Sentinel.Password,
+			Username:         cfg.Sentinel.Username,
+			Password:         cfg.Sentinel.Password,
+			ClientName:       cfg.Sentinel.ClientName,
+		}
+		client = valkey.NewFailoverClusterClient(opts)
+	default:
+		opts, err := valkey.ParseURL(cfg.URL)
+		if err != nil {
+			return nil, fmt.Errorf("valkey.Factory: %w", err)
+		}
+
 		opts.MaintNotificationsConfig = &maintnotifications.Config{
 			Mode: maintnotifications.ModeDisabled,
 		}