Add support for the PostStart event handler.

pkg/kubelet/handlers.go

@@ -0,0 +1,97 @@
+/*
+Copyright 2014 Google Inc. 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 kubelet
+
+import (
+	"fmt"
+	"net"
+	"strconv"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+	"github.com/golang/glog"
+)
+
+type execActionHandler struct {
+	kubelet *Kubelet
+}
+
+func (e *execActionHandler) Run(podFullName string, container *api.Container, handler *api.Handler) error {
+	_, err := e.kubelet.RunInContainer(podFullName, container.Name, handler.Exec.Command)
+	return err
+}
+
+type httpActionHandler struct {
+	kubelet *Kubelet
+	client  httpGetInterface
+}
+
+// ResolvePort attempts to turn a IntOrString port reference into a concrete port number.
+// If portReference has an int value, it is treated as a literal, and simply returns that value.
+// If portReference is a string, an attempt is first made to parse it as an integer.  If that fails,
+// an attempt is made to find a port with the same name in the container spec.
+// If a port with the same name is found, it's ContainerPort value is returned.  If no matching
+// port is found, an error is returned.
+func ResolvePort(portReference util.IntOrString, container *api.Container) (int, error) {
+	if portReference.Kind == util.IntstrInt {
+		return portReference.IntVal, nil
+	} else {
+		portName := portReference.StrVal
+		port, err := strconv.Atoi(portName)
+		if err == nil {
+			return port, nil
+		}
+		for _, portSpec := range container.Ports {
+			if portSpec.Name == portName {
+				return portSpec.ContainerPort, nil
+			}
+		}
+
+	}
+	return -1, fmt.Errorf("couldn't find port: %v in %v", portReference, container)
+}
+
+func (h *httpActionHandler) Run(podFullName string, container *api.Container, handler *api.Handler) error {
+	host := handler.HTTPGet.Host
+	if len(host) == 0 {
+		var info api.PodInfo
+		info, err := h.kubelet.GetPodInfo(podFullName)
+		if err != nil {
+			glog.Errorf("unable to get pod info, event handlers may be invalid.")
+			return err
+		}
+		netInfo, found := info[networkContainerName]
+		if found && netInfo.NetworkSettings != nil {
+			host = netInfo.NetworkSettings.IPAddress
+		} else {
+			return fmt.Errorf("failed to find networking container: %v", info)
+		}
+	}
+	var port int
+	if handler.HTTPGet.Port.Kind == util.IntstrString && len(handler.HTTPGet.Port.StrVal) == 0 {
+		port = 80
+	} else {
+		var err error
+		port, err = ResolvePort(handler.HTTPGet.Port, container)
+		if err != nil {
+			return err
+		}
+	}
+	url := fmt.Sprintf("http://%s/%s", net.JoinHostPort(host, strconv.Itoa(port)), handler.HTTPGet.Path)
+	_, err := h.client.Get(url)
+	return err
+}

pkg/kubelet/handlers_test.go

@@ -0,0 +1,69 @@
+/*
+Copyright 2014 Google Inc. 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 kubelet
+
+import (
+	"testing"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+)
+
+func TestResolvePortInt(t *testing.T) {
+	expected := 80
+	port, err := ResolvePort(util.IntOrString{Kind: util.IntstrInt, IntVal: expected}, &api.Container{})
+	if port != expected {
+		t.Errorf("expected: %d, saw: %d", port)
+	}
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+}
+
+func TestResolvePortString(t *testing.T) {
+	expected := 80
+	name := "foo"
+	container := &api.Container{
+		Ports: []api.Port{
+			{Name: name, ContainerPort: expected},
+		},
+	}
+	port, err := ResolvePort(util.IntOrString{Kind: util.IntstrString, StrVal: name}, container)
+	if port != expected {
+		t.Errorf("expected: %d, saw: %d", port)
+	}
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+}
+
+func TestResolvePortStringUnknown(t *testing.T) {
+	expected := 80
+	name := "foo"
+	container := &api.Container{
+		Ports: []api.Port{
+			{Name: "bar", ContainerPort: expected},
+		},
+	}
+	port, err := ResolvePort(util.IntOrString{Kind: util.IntstrString, StrVal: name}, container)
+	if port != -1 {
+		t.Errorf("expected: -1, saw: %d", port)
+	}
+	if err == nil {
+		t.Error("unexpected non-error")
+	}
+}

pkg/kubelet/kubelet.go

@@ -76,6 +76,7 @@ func NewMainKubelet(
 		resyncInterval: ri,
 		podWorkers:     newPodWorkers(),
 		runner:         NewDockerContainerCommandRunner(),
+		httpClient:     &http.Client{},
 	}
 }
 
@@ -95,6 +96,10 @@ type ContainerCommandRunner interface {
 	RunInContainer(containerID string, cmd []string) ([]byte, error)
 }
 
+type httpGetInterface interface {
+	Get(url string) (*http.Response, error)
+}
+
 // Kubelet is the main kubelet implementation.
 type Kubelet struct {
 	hostname       string
@@ -115,6 +120,8 @@ type Kubelet struct {
 	logServer http.Handler
 	// Optional, defaults to simple Docker implementation
 	runner ContainerCommandRunner
+	// Optional, client for http requests, defaults to empty client
+	httpClient httpGetInterface
 }
 
 // Run starts the kubelet reacting to config updates
@@ -283,6 +290,31 @@ func (kl *Kubelet) mountExternalVolumes(manifest *api.ContainerManifest) (volume
 	return podVolumes, nil
 }
 
+// A basic interface that knows how to execute handlers
+type actionHandler interface {
+	Run(podFullName string, container *api.Container, handler *api.Handler) error
+}
+
+func (kl *Kubelet) newActionHandler(handler *api.Handler) actionHandler {
+	switch {
+	case handler.Exec != nil:
+		return &execActionHandler{kubelet: kl}
+	case handler.HTTPGet != nil:
+		return &httpActionHandler{client: kl.httpClient, kubelet: kl}
+	default:
+		glog.Errorf("Invalid handler: %v")
+		return nil
+	}
+}
+
+func (kl *Kubelet) runHandler(podFullName string, container *api.Container, handler *api.Handler) error {
+	actionHandler := kl.newActionHandler(handler)
+	if actionHandler == nil {
+		return fmt.Errorf("invalid handler")
+	}
+	return actionHandler.Run(podFullName, container, handler)
+}
+
 // Run a single container from a pod. Returns the docker container ID
 func (kl *Kubelet) runContainer(pod *Pod, container *api.Container, podVolumes volumeMap, netMode string) (id DockerID, err error) {
 	envVariables := makeEnvironmentVariables(container)
@@ -311,14 +343,28 @@ func (kl *Kubelet) runContainer(pod *Pod, container *api.Container, podVolumes v
 		Binds:        binds,
 		NetworkMode:  netMode,
 	})
+	if err == nil && container.Lifecycle != nil && container.Lifecycle.PostStart != nil {
+		handlerErr := kl.runHandler(GetPodFullName(pod), container, container.Lifecycle.PostStart)
+		if handlerErr != nil {
+			kl.killContainerByID(dockerContainer.ID, "")
+			return DockerID(""), fmt.Errorf("failed to call event handler: %v", handlerErr)
+		}
+	}
 	return DockerID(dockerContainer.ID), err
 }
 
 // Kill a docker container
 func (kl *Kubelet) killContainer(dockerContainer *docker.APIContainers) error {
-	glog.Infof("Killing: %s", dockerContainer.ID)
-	err := kl.dockerClient.StopContainer(dockerContainer.ID, 10)
-	podFullName, containerName, _ := parseDockerName(dockerContainer.Names[0])
+	return kl.killContainerByID(dockerContainer.ID, dockerContainer.Names[0])
+}
+
+func (kl *Kubelet) killContainerByID(ID, name string) error {
+	glog.Infof("Killing: %s", ID)
+	err := kl.dockerClient.StopContainer(ID, 10)
+	if len(name) == 0 {
+		return err
+	}
+	podFullName, containerName, _ := parseDockerName(name)
 	kl.LogEvent(&api.Event{
 		Event: "STOP",
 		Manifest: &api.ContainerManifest{

pkg/kubelet/kubelet_test.go

@@ -20,6 +20,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"hash/adler32"
+	"net/http"
 	"reflect"
 	"regexp"
 	"strconv"
@@ -30,6 +31,7 @@ import (
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/health"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/tools"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/volume"
 	"github.com/fsouza/go-dockerclient"
 	"github.com/google/cadvisor/info"
@@ -346,6 +348,59 @@ func TestSyncPodsWithNetCreatesContainer(t *testing.T) {
 	fakeDocker.lock.Unlock()
 }
 
+func TestSyncPodsWithNetCreatesContainerCallsHandler(t *testing.T) {
+	kubelet, _, fakeDocker := newTestKubelet(t)
+	fakeHttp := fakeHTTP{}
+	kubelet.httpClient = &fakeHttp
+	fakeDocker.containerList = []docker.APIContainers{
+		{
+			// network container
+			Names: []string{"/k8s--net--foo.test--"},
+			ID:    "9876",
+		},
+	}
+	err := kubelet.SyncPods([]Pod{
+		{
+			Name:      "foo",
+			Namespace: "test",
+			Manifest: api.ContainerManifest{
+				ID: "foo",
+				Containers: []api.Container{
+					{
+						Name: "bar",
+						Lifecycle: &api.Lifecycle{
+							PostStart: &api.Handler{
+								HTTPGet: &api.HTTPGetAction{
+									Host: "foo",
+									Port: util.IntOrString{IntVal: 8080, Kind: util.IntstrInt},
+									Path: "bar",
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	})
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+	kubelet.drainWorkers()
+
+	verifyCalls(t, fakeDocker, []string{
+		"list", "list", "list", "inspect", "create", "start"})
+
+	fakeDocker.lock.Lock()
+	if len(fakeDocker.Created) != 1 ||
+		!matchString(t, "k8s--bar\\.[a-f0-9]+--foo.test--", fakeDocker.Created[0]) {
+		t.Errorf("Unexpected containers created %v", fakeDocker.Created)
+	}
+	fakeDocker.lock.Unlock()
+	if fakeHttp.url != "http://foo:8080/bar" {
+		t.Errorf("Unexpected handler: %s", fakeHttp.url)
+	}
+}
+
 func TestSyncPodsDeletesWithNoNetContainer(t *testing.T) {
 	kubelet, _, fakeDocker := newTestKubelet(t)
 	fakeDocker.containerList = []docker.APIContainers{
@@ -1126,3 +1181,155 @@ func TestParseImageName(t *testing.T) {
 		}
 	}
 }
+
+func TestRunHandlerExec(t *testing.T) {
+	fakeCommandRunner := fakeContainerCommandRunner{}
+	kubelet, _, fakeDocker := newTestKubelet(t)
+	kubelet.runner = &fakeCommandRunner
+
+	containerID := "abc1234"
+	podName := "podFoo"
+	podNamespace := "etcd"
+	containerName := "containerFoo"
+
+	fakeDocker.containerList = []docker.APIContainers{
+		{
+			ID:    containerID,
+			Names: []string{"/k8s--" + containerName + "--" + podName + "." + podNamespace + "--1234"},
+		},
+	}
+
+	container := api.Container{
+		Name: containerName,
+		Lifecycle: &api.Lifecycle{
+			PostStart: &api.Handler{
+				Exec: &api.ExecAction{
+					Command: []string{"ls", "-a"},
+				},
+			},
+		},
+	}
+	err := kubelet.runHandler(podName+"."+podNamespace, &container, container.Lifecycle.PostStart)
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+	if fakeCommandRunner.ID != containerID ||
+		!reflect.DeepEqual(container.Lifecycle.PostStart.Exec.Command, fakeCommandRunner.Cmd) {
+		t.Errorf("unexpected commands: %v", fakeCommandRunner)
+	}
+}
+
+type fakeHTTP struct {
+	url string
+	err error
+}
+
+func (f *fakeHTTP) Get(url string) (*http.Response, error) {
+	f.url = url
+	return nil, f.err
+}
+
+func TestRunHandlerHttp(t *testing.T) {
+	fakeHttp := fakeHTTP{}
+
+	kubelet, _, _ := newTestKubelet(t)
+	kubelet.httpClient = &fakeHttp
+
+	podName := "podFoo"
+	podNamespace := "etcd"
+	containerName := "containerFoo"
+
+	container := api.Container{
+		Name: containerName,
+		Lifecycle: &api.Lifecycle{
+			PostStart: &api.Handler{
+				HTTPGet: &api.HTTPGetAction{
+					Host: "foo",
+					Port: util.IntOrString{IntVal: 8080, Kind: util.IntstrInt},
+					Path: "bar",
+				},
+			},
+		},
+	}
+	err := kubelet.runHandler(podName+"."+podNamespace, &container, container.Lifecycle.PostStart)
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+	if fakeHttp.url != "http://foo:8080/bar" {
+		t.Errorf("unexpected url: %s", fakeHttp.url)
+	}
+}
+
+func TestNewHandler(t *testing.T) {
+	kubelet, _, _ := newTestKubelet(t)
+	handler := &api.Handler{
+		HTTPGet: &api.HTTPGetAction{
+			Host: "foo",
+			Port: util.IntOrString{IntVal: 8080, Kind: util.IntstrInt},
+			Path: "bar",
+		},
+	}
+	actionHandler := kubelet.newActionHandler(handler)
+	if actionHandler == nil {
+		t.Error("unexpected nil action handler.")
+	}
+
+	handler = &api.Handler{
+		Exec: &api.ExecAction{
+			Command: []string{"ls", "-l"},
+		},
+	}
+	actionHandler = kubelet.newActionHandler(handler)
+	if actionHandler == nil {
+		t.Error("unexpected nil action handler.")
+	}
+
+	handler = &api.Handler{}
+	actionHandler = kubelet.newActionHandler(handler)
+	if actionHandler != nil {
+		t.Errorf("unexpected non-nil action handler: %v", actionHandler)
+	}
+}
+
+func TestSyncPodEventHandlerFails(t *testing.T) {
+	kubelet, _, fakeDocker := newTestKubelet(t)
+	kubelet.httpClient = &fakeHTTP{
+		err: fmt.Errorf("test error"),
+	}
+	dockerContainers := DockerContainers{
+		"9876": &docker.APIContainers{
+			// network container
+			Names: []string{"/k8s--net--foo.test--"},
+			ID:    "9876",
+		},
+	}
+	err := kubelet.syncPod(&Pod{
+		Name:      "foo",
+		Namespace: "test",
+		Manifest: api.ContainerManifest{
+			ID: "foo",
+			Containers: []api.Container{
+				{Name: "bar",
+					Lifecycle: &api.Lifecycle{
+						PostStart: &api.Handler{
+							HTTPGet: &api.HTTPGetAction{
+								Host: "does.no.exist",
+								Port: util.IntOrString{IntVal: 8080, Kind: util.IntstrInt},
+								Path: "bar",
+							},
+						},
+					},
+				},
+			},
+		},
+	}, dockerContainers)
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+
+	verifyCalls(t, fakeDocker, []string{"list", "create", "start", "stop"})
+
+	if len(fakeDocker.stopped) != 1 {
+		t.Errorf("Wrong containers were stopped: %v", fakeDocker.stopped)
+	}
+}