Split implementations from generic code

core/pkg/ingress/annotations/service/service.go

@@ -0,0 +1,73 @@
+/*
+Copyright 2015 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package service
+
+import (
+	"encoding/json"
+	"fmt"
+	"strconv"
+
+	"k8s.io/kubernetes/pkg/api"
+
+	"github.com/golang/glog"
+)
+
+const (
+	// NamedPortAnnotation annotation used to map named port in services
+	NamedPortAnnotation = "ingress.kubernetes.io/named-ports"
+)
+
+type namedPortMapping map[string]string
+
+// getPort returns the port defined in a named port
+func (npm namedPortMapping) getPort(name string) (string, bool) {
+	val, ok := npm.getPortMappings()[name]
+	return val, ok
+}
+
+// getPortMappings returns a map containing the mapping of named ports names and number
+func (npm namedPortMapping) getPortMappings() map[string]string {
+	data := npm[NamedPortAnnotation]
+	var mapping map[string]string
+	if data == "" {
+		return mapping
+	}
+	if err := json.Unmarshal([]byte(data), &mapping); err != nil {
+		glog.Errorf("unexpected error reading annotations: %v", err)
+	}
+
+	return mapping
+}
+
+// GetPortMapping returns the number of the named port or an error if is not valid
+func GetPortMapping(name string, s *api.Service) (int32, error) {
+	if s == nil {
+		return -1, fmt.Errorf("impossible to extract por mapping from %v (missing service)", name)
+	}
+	namedPorts := s.ObjectMeta.Annotations
+	val, ok := namedPortMapping(namedPorts).getPort(name)
+	if ok {
+		port, err := strconv.Atoi(val)
+		if err != nil {
+			return -1, fmt.Errorf("service %v contains an invalid port mapping for %v (%v), %v", s.Name, name, val, err)
+		}
+
+		return int32(port), nil
+	}
+
+	return -1, fmt.Errorf("there is no port with name %v", name)
+}