Add support for ConfigMap keys in env vars

pkg/api/types.go

@@ -715,9 +715,12 @@ type EnvVar struct {
 }
 
 // EnvVarSource represents a source for the value of an EnvVar.
+// Only one of its fields may be set.
 type EnvVarSource struct {
-	// Required: Selects a field of the pod; only name and namespace are supported.
-	FieldRef *ObjectFieldSelector `json:"fieldRef"`
+	// Selects a field of the pod; only name and namespace are supported.
+	FieldRef *ObjectFieldSelector `json:"fieldRef,omitempty"`
+	// Selects a key of a ConfigMap.
+	ConfigMapKeyRef *ConfigMapKeySelector `json:"configMapKeyRef,omitempty"`
 }
 
 // ObjectFieldSelector selects an APIVersioned field of an object.
@@ -730,6 +733,14 @@ type ObjectFieldSelector struct {
 	FieldPath string `json:"fieldPath"`
 }
 
+// Selects a key from a ConfigMap.
+type ConfigMapKeySelector struct {
+	// The ConfigMap to select from.
+	LocalObjectReference `json:",inline"`
+	// The key to select.
+	Key string `json:"key"`
+}
+
 // HTTPGetAction describes an action based on HTTP Get requests.
 type HTTPGetAction struct {
 	// Optional: Path to access on the HTTP server.

pkg/api/v1/types.go

@@ -843,8 +843,10 @@ type EnvVar struct {
 
 // EnvVarSource represents a source for the value of an EnvVar.
 type EnvVarSource struct {
-	// Selects a field of the pod. Only name and namespace are supported.
-	FieldRef *ObjectFieldSelector `json:"fieldRef"`
+	// Selects a field of the pod; only name and namespace are supported.
+	FieldRef *ObjectFieldSelector `json:"fieldRef,omitempty"`
+	// Selects a key of a ConfigMap.
+	ConfigMapKeyRef *ConfigMapKeySelector `json:"configMapKeyRef,omitempty"`
 }
 
 // ObjectFieldSelector selects an APIVersioned field of an object.
@@ -855,6 +857,14 @@ type ObjectFieldSelector struct {
 	FieldPath string `json:"fieldPath"`
 }
 
+// Selects a key from a ConfigMap.
+type ConfigMapKeySelector struct {
+	// The ConfigMap to select from.
+	LocalObjectReference `json:",inline"`
+	// The key to select.
+	Key string `json:"key"`
+}
+
 // HTTPGetAction describes an action based on HTTP Get requests.
 type HTTPGetAction struct {
 	// Path to access on the HTTP server.

pkg/api/validation/validation.go

@@ -968,6 +968,9 @@ func validateEnvVarValueFrom(ev api.EnvVar, fldPath *field.Path) field.ErrorList
 	case ev.ValueFrom.FieldRef != nil:
 		numSources++
 		allErrs = append(allErrs, validateObjectFieldSelector(ev.ValueFrom.FieldRef, &validFieldPathExpressionsEnv, fldPath.Child("fieldRef"))...)
+	case ev.ValueFrom.ConfigMapKeyRef != nil:
+		numSources++
+		allErrs = append(allErrs, validateConfigMapKeySelector(ev.ValueFrom.ConfigMapKeyRef, fldPath.Child("configMapKeyRef"))...)
 	}
 
 	if len(ev.Value) != 0 && numSources != 0 {
@@ -996,6 +999,21 @@ func validateObjectFieldSelector(fs *api.ObjectFieldSelector, expressions *sets.
 	return allErrs
 }
 
+func validateConfigMapKeySelector(s *api.ConfigMapKeySelector, fldPath *field.Path) field.ErrorList {
+	allErrs := field.ErrorList{}
+
+	if len(s.Name) == 0 {
+		allErrs = append(allErrs, field.Required(fldPath.Child("name"), ""))
+	}
+	if len(s.Key) == 0 {
+		allErrs = append(allErrs, field.Required(fldPath.Child("key"), ""))
+	} else if !IsSecretKey(s.Key) {
+		allErrs = append(allErrs, field.Invalid(fldPath.Child("key"), s.Key, fmt.Sprintf("must have at most %d characters and match regex %s", validation.DNS1123SubdomainMaxLength, SecretKeyFmt)))
+	}
+
+	return allErrs
+}
+
 func validateVolumeMounts(mounts []api.VolumeMount, volumes sets.String, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 

pkg/kubelet/kubelet.go

@@ -40,6 +40,7 @@ import (
 	"k8s.io/kubernetes/pkg/api/resource"
 	"k8s.io/kubernetes/pkg/api/unversioned"
 	"k8s.io/kubernetes/pkg/api/validation"
+	apiextensions "k8s.io/kubernetes/pkg/apis/extensions"
 	"k8s.io/kubernetes/pkg/client/cache"
 	"k8s.io/kubernetes/pkg/client/record"
 	client "k8s.io/kubernetes/pkg/client/unversioned"
@@ -1391,9 +1392,11 @@ func (kl *Kubelet) makeEnvironmentVariables(pod *api.Pod, container *api.Contain
 	//     b.  If a source is defined for an environment variable, resolve the source
 	// 2.  Create the container's environment in the order variables are declared
 	// 3.  Add remaining service environment vars
-
-	tmpEnv := make(map[string]string)
-	mappingFunc := expansion.MappingFuncFor(tmpEnv, serviceEnv)
+	var (
+		tmpEnv      = make(map[string]string)
+		configMaps  = make(map[string]*apiextensions.ConfigMap)
+		mappingFunc = expansion.MappingFuncFor(tmpEnv, serviceEnv)
+	)
 	for _, envVar := range container.Env {
 		// Accesses apiserver+Pods.
 		// So, the master may set service env vars, or kubelet may.  In case both are doing
@@ -1406,11 +1409,28 @@ func (kl *Kubelet) makeEnvironmentVariables(pod *api.Pod, container *api.Contain
 		if runtimeVal != "" {
 			// Step 1a: expand variable references
 			runtimeVal = expansion.Expand(runtimeVal, mappingFunc)
-		} else if envVar.ValueFrom != nil && envVar.ValueFrom.FieldRef != nil {
+		} else if envVar.ValueFrom != nil {
 			// Step 1b: resolve alternate env var sources
-			runtimeVal, err = kl.podFieldSelectorRuntimeValue(envVar.ValueFrom.FieldRef, pod)
-			if err != nil {
-				return result, err
+			switch {
+			case envVar.ValueFrom.FieldRef != nil:
+				runtimeVal, err = kl.podFieldSelectorRuntimeValue(envVar.ValueFrom.FieldRef, pod)
+				if err != nil {
+					return result, err
+				}
+			case envVar.ValueFrom.ConfigMapKeyRef != nil:
+				name := envVar.ValueFrom.ConfigMapKeyRef.Name
+				key := envVar.ValueFrom.ConfigMapKeyRef.Key
+				configMap, ok := configMaps[name]
+				if !ok {
+					configMap, err = kl.kubeClient.Extensions().ConfigMaps(pod.Namespace).Get(name)
+					if err != nil {
+						return result, err
+					}
+				}
+				runtimeVal, ok = configMap.Data[key]
+				if !ok {
+					return result, fmt.Errorf("Couldn't find key %v in ConfigMap %v/%v", key, pod.Namespace, name)
+				}
 			}
 		}
 

test/e2e/configmap.go

@@ -0,0 +1,91 @@
+/*
+Copyright 2014 The Kubernetes Authors All rights reserved.
+
+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 e2e
+
+import (
+	"fmt"
+
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/apis/extensions"
+	"k8s.io/kubernetes/pkg/util"
+
+	. "github.com/onsi/ginkgo"
+)
+
+var _ = Describe("ConfigMap", func() {
+	f := NewFramework("configmap")
+
+	It("should be consumable via environment variable [Conformance]", func() {
+		name := "configmap-test-" + string(util.NewUUID())
+		configMap := &extensions.ConfigMap{
+			ObjectMeta: api.ObjectMeta{
+				Namespace: f.Namespace.Name,
+				Name:      name,
+			},
+			Data: map[string]string{
+				"data-1": "value-1",
+				"data-2": "value-2",
+				"data-3": "value-3",
+			},
+		}
+
+		By(fmt.Sprintf("Creating configMap %v/%v", f.Namespace.Name, configMap.Name))
+		defer func() {
+			By("Cleaning up the configMap")
+			if err := f.Client.Extensions().ConfigMaps(f.Namespace.Name).Delete(configMap.Name); err != nil {
+				Failf("unable to delete configMap %v: %v", configMap.Name, err)
+			}
+		}()
+		var err error
+		if configMap, err = f.Client.Extensions().ConfigMaps(f.Namespace.Name).Create(configMap); err != nil {
+			Failf("unable to create test configMap %s: %v", configMap.Name, err)
+		}
+
+		pod := &api.Pod{
+			ObjectMeta: api.ObjectMeta{
+				Name: "pod-configmaps-" + string(util.NewUUID()),
+			},
+			Spec: api.PodSpec{
+				Containers: []api.Container{
+					{
+						Name:    "env-test",
+						Image:   "gcr.io/google_containers/busybox",
+						Command: []string{"sh", "-c", "env"},
+						Env: []api.EnvVar{
+							{
+								Name: "CONFIG_DATA_1",
+								ValueFrom: &api.EnvVarSource{
+									ConfigMapKeyRef: &api.ConfigMapKeySelector{
+										LocalObjectReference: api.LocalObjectReference{
+											Name: name,
+										},
+										Key: "data-1",
+									},
+								},
+							},
+						},
+					},
+				},
+				RestartPolicy: api.RestartPolicyNever,
+			},
+		}
+
+		testContainerOutput("consume configMaps", f.Client, pod, 0, []string{
+			"CONFIG_DATA_1=value-1",
+		}, f.Namespace.Name)
+	})
+})