Add a in container exec based health check.

pkg/health/exec.go

@@ -0,0 +1,59 @@
+/*
+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 health
+
+import (
+	"fmt"
+	"os/exec"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/golang/glog"
+)
+
+const defaultHealthyRegex = "^OK$"
+
+type CommandRunner interface {
+	RunInContainer(podFullName, containerName string, cmd []string) ([]byte, error)
+}
+
+type ExecHealthChecker struct {
+	runner CommandRunner
+}
+
+func NewExecHealthChecker(runner CommandRunner) HealthChecker {
+	return &ExecHealthChecker{runner}
+}
+
+func IsExitError(err error) bool {
+	_, ok := err.(*exec.ExitError)
+	return ok
+}
+
+func (e *ExecHealthChecker) HealthCheck(podFullName string, currentState api.PodState, container api.Container) (Status, error) {
+	if container.LivenessProbe.Exec == nil {
+		return Unknown, fmt.Errorf("Missing exec parameters")
+	}
+	data, err := e.runner.RunInContainer(podFullName, container.Name, container.LivenessProbe.Exec.Command)
+	glog.V(1).Infof("container %s failed health check: %s", podFullName, string(data))
+	if err != nil {
+		if IsExitError(err) {
+			return Unhealthy, nil
+		}
+		return Unknown, err
+	}
+	return Healthy, nil
+}