fix: Parse number Durations in config correctly (fix #221)

This error edge case was introduced by #218.

pkg/edition/java/lite/config/config.go

@@ -30,7 +30,7 @@ type (
 	Route struct {
 		Host          configutil.SingleOrMulti[string] `json:"host" yaml:"host"`
 		Backend       configutil.SingleOrMulti[string] `json:"backend" yaml:"backend"`
-		CachePingTTL  time.Duration                    `json:"cachePingTTL,omitempty" yaml:"cachePingTTL,omitempty"` // 0 = default, < 0 = disabled
+		CachePingTTL  configutil.Duration              `json:"cachePingTTL,omitempty" yaml:"cachePingTTL,omitempty"` // 0 = default, < 0 = disabled
 		Fallback      *Status                          `json:"fallback,omitempty" yaml:"fallback,omitempty"`         // nil = disabled
 		ProxyProtocol bool                             `json:"proxyProtocol,omitempty" yaml:"proxyProtocol,omitempty"`
 		RealIP        bool                             `json:"realIP,omitempty" yaml:"realIP,omitempty"`
@@ -73,7 +73,7 @@ func (r *Route) GetCachePingTTL() time.Duration {
 	if r.CachePingTTL == 0 {
 		return defaultTTL
 	}
-	return r.CachePingTTL
+	return time.Duration(r.CachePingTTL)
 }
 
 // CachePingEnabled returns true if the route has a ping cache enabled.

pkg/util/configutil/duration.go

@@ -0,0 +1,40 @@
+package configutil
+
+import (
+	"encoding/json"
+	"fmt"
+	"time"
+)
+
+// Duration is a configuration duration.
+// It is a wrapper around time.Duration that implements the json.Marshaler and json.Unmarshaler interfaces.
+//
+//   - string is parsed using time.ParseDuration.
+//   - int64 and float64 are interpreted as seconds.
+type Duration time.Duration
+
+func (d *Duration) MarshalJSON() ([]byte, error) {
+	return json.Marshal(time.Duration(*d).String())
+}
+
+func (d *Duration) UnmarshalJSON(data []byte) error {
+	var a any
+	if err := json.Unmarshal(data, &a); err != nil {
+		return err
+	}
+	switch v := a.(type) {
+	case string:
+		dur, err := time.ParseDuration(v)
+		if err != nil {
+			return err
+		}
+		*d = Duration(dur)
+	case float64:
+		*d = Duration(time.Duration(v) * time.Second)
+	case int64:
+		*d = Duration(time.Duration(v) * time.Second)
+	default:
+		return fmt.Errorf("invalid duration type %T: %v", v, v)
+	}
+	return nil
+}