add selector

selector/selector.go

@@ -0,0 +1,54 @@
+package selector
+
+import (
+	"time"
+
+	"github.com/go-gost/core/chain"
+	"github.com/go-gost/core/selector"
+)
+
+// default options for FailFilter
+const (
+	DefaultMaxFails    = 1
+	DefaultFailTimeout = 10 * time.Second
+)
+
+const (
+	labelWeight      = "weight"
+	labelBackup      = "backup"
+	labelMaxFails    = "maxFails"
+	labelFailTimeout = "failTimeout"
+)
+
+var (
+	DefaultNodeSelector = NewSelector(
+		RoundRobinStrategy[*chain.Node](),
+		// FailFilter[*Node](1, DefaultFailTimeout),
+	)
+	DefaultChainSelector = NewSelector(
+		RoundRobinStrategy[chain.SelectableChainer](),
+		// FailFilter[SelectableChainer](1, DefaultFailTimeout),
+	)
+)
+
+type defaultSelector[T selector.Selectable] struct {
+	strategy selector.Strategy[T]
+	filters  []selector.Filter[T]
+}
+
+func NewSelector[T selector.Selectable](strategy selector.Strategy[T], filters ...selector.Filter[T]) selector.Selector[T] {
+	return &defaultSelector[T]{
+		filters:  filters,
+		strategy: strategy,
+	}
+}
+
+func (s *defaultSelector[T]) Select(vs ...T) (v T) {
+	for _, filter := range s.filters {
+		vs = filter.Filter(vs...)
+	}
+	if len(vs) == 0 {
+		return
+	}
+	return s.strategy.Apply(vs...)
+}