new e2e framework (#1835)

test/e2e/pkg/port/port.go

@@ -0,0 +1,57 @@
+package port
+
+import (
+	"fmt"
+	"net"
+
+	"k8s.io/apimachinery/pkg/util/sets"
+)
+
+type Allocator struct {
+	reserved sets.Int
+	used     sets.Int
+}
+
+// NewAllocator return a port allocator for testing.
+// Example: from: 10, to: 20, mod 4, index 1
+// Reserved ports: 13, 17
+func NewAllocator(from int, to int, mod int, index int) *Allocator {
+	pa := &Allocator{
+		reserved: sets.NewInt(),
+		used:     sets.NewInt(),
+	}
+	for i := from; i <= to; i++ {
+		if i%mod == index {
+			pa.reserved.Insert(i)
+		}
+	}
+	return pa
+}
+
+func (pa *Allocator) Get() int {
+	for i := 0; i < 10; i++ {
+		port, _ := pa.reserved.PopAny()
+		if port == 0 {
+			return 0
+		}
+
+		// TODO: Distinguish between TCP and UDP
+		l, err := net.Listen("tcp", fmt.Sprintf("127.0.0.1:%d", port))
+		if err != nil {
+			// Maybe not controlled by us, mark it used.
+			pa.used.Insert(port)
+			continue
+		}
+		l.Close()
+		pa.used.Insert(port)
+		return port
+	}
+	return 0
+}
+
+func (pa *Allocator) Release(port int) {
+	if pa.used.Has(port) {
+		pa.used.Delete(port)
+		pa.reserved.Insert(port)
+	}
+}