Set container env var using services. (#573)

* Introduce service env vars.

vendor/k8s.io/kubernetes/pkg/kubelet/envvars/doc.go

@@ -0,0 +1,19 @@
+/*
+Copyright 2014 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 envvars is the package that build the environment variables that kubernetes provides
+// to the containers run by it.
+package envvars // import "k8s.io/kubernetes/pkg/kubelet/envvars"

vendor/k8s.io/kubernetes/pkg/kubelet/envvars/envvars.go

@@ -0,0 +1,113 @@
+/*
+Copyright 2014 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 envvars
+
+import (
+	"fmt"
+	"net"
+	"strconv"
+	"strings"
+
+	"k8s.io/api/core/v1"
+	v1helper "k8s.io/kubernetes/pkg/apis/core/v1/helper"
+)
+
+// FromServices builds environment variables that a container is started with,
+// which tell the container where to find the services it may need, which are
+// provided as an argument.
+func FromServices(services []*v1.Service) []v1.EnvVar {
+	var result []v1.EnvVar
+	for i := range services {
+		service := services[i]
+
+		// ignore services where ClusterIP is "None" or empty
+		// the services passed to this method should be pre-filtered
+		// only services that have the cluster IP set should be included here
+		if !v1helper.IsServiceIPSet(service) {
+			continue
+		}
+
+		// Host
+		name := makeEnvVariableName(service.Name) + "_SERVICE_HOST"
+		result = append(result, v1.EnvVar{Name: name, Value: service.Spec.ClusterIP})
+		// First port - give it the backwards-compatible name
+		name = makeEnvVariableName(service.Name) + "_SERVICE_PORT"
+		result = append(result, v1.EnvVar{Name: name, Value: strconv.Itoa(int(service.Spec.Ports[0].Port))})
+		// All named ports (only the first may be unnamed, checked in validation)
+		for i := range service.Spec.Ports {
+			sp := &service.Spec.Ports[i]
+			if sp.Name != "" {
+				pn := name + "_" + makeEnvVariableName(sp.Name)
+				result = append(result, v1.EnvVar{Name: pn, Value: strconv.Itoa(int(sp.Port))})
+			}
+		}
+		// Docker-compatible vars.
+		result = append(result, makeLinkVariables(service)...)
+	}
+	return result
+}
+
+func makeEnvVariableName(str string) string {
+	// TODO: If we simplify to "all names are DNS1123Subdomains" this
+	// will need two tweaks:
+	//   1) Handle leading digits
+	//   2) Handle dots
+	return strings.ToUpper(strings.Replace(str, "-", "_", -1))
+}
+
+func makeLinkVariables(service *v1.Service) []v1.EnvVar {
+	prefix := makeEnvVariableName(service.Name)
+	all := []v1.EnvVar{}
+	for i := range service.Spec.Ports {
+		sp := &service.Spec.Ports[i]
+
+		protocol := string(v1.ProtocolTCP)
+		if sp.Protocol != "" {
+			protocol = string(sp.Protocol)
+		}
+
+		hostPort := net.JoinHostPort(service.Spec.ClusterIP, strconv.Itoa(int(sp.Port)))
+
+		if i == 0 {
+			// Docker special-cases the first port.
+			all = append(all, v1.EnvVar{
+				Name:  prefix + "_PORT",
+				Value: fmt.Sprintf("%s://%s", strings.ToLower(protocol), hostPort),
+			})
+		}
+		portPrefix := fmt.Sprintf("%s_PORT_%d_%s", prefix, sp.Port, strings.ToUpper(protocol))
+		all = append(all, []v1.EnvVar{
+			{
+				Name:  portPrefix,
+				Value: fmt.Sprintf("%s://%s", strings.ToLower(protocol), hostPort),
+			},
+			{
+				Name:  portPrefix + "_PROTO",
+				Value: strings.ToLower(protocol),
+			},
+			{
+				Name:  portPrefix + "_PORT",
+				Value: strconv.Itoa(int(sp.Port)),
+			},
+			{
+				Name:  portPrefix + "_ADDR",
+				Value: service.Spec.ClusterIP,
+			},
+		}...)
+	}
+	return all
+}