Split health_check.go into smaller parts.

Distinct files for core, http, and tcp.

pkg/health/http.go

@@ -0,0 +1,101 @@
+/*
+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"
+	"net/http"
+	"strconv"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+	"github.com/golang/glog"
+)
+
+// HTTPGetInterface is an abstract interface for testability. It abstracts the interface of http.Client.Get.
+type HTTPGetInterface interface {
+	Get(url string) (*http.Response, error)
+}
+
+// DoHTTPCheck checks if a GET request to the url succeeds.
+// HTTPHealthChecker is an implementation of HealthChecker which checks container health by sending HTTP Get requests.
+type HTTPHealthChecker struct {
+	client HTTPGetInterface
+}
+
+// Get the components of the target URL.  For testability.
+func getURLParts(currentState api.PodState, container api.Container) (string, int, string, error) {
+	params := container.LivenessProbe.HTTPGet
+	if params == nil {
+		return "", -1, "", fmt.Errorf("no HTTP parameters specified: %v", container)
+	}
+	port := -1
+	switch params.Port.Kind {
+	case util.IntstrInt:
+		port = params.Port.IntVal
+	case util.IntstrString:
+		port = findPortByName(container, params.Port.StrVal)
+		if port == -1 {
+			// Last ditch effort - maybe it was an int stored as string?
+			var err error
+			if port, err = strconv.Atoi(params.Port.StrVal); err != nil {
+				return "", -1, "", err
+			}
+		}
+	}
+	if port == -1 {
+		return "", -1, "", fmt.Errorf("unknown port: %v", params.Port)
+	}
+	var host string
+	if len(params.Host) > 0 {
+		host = params.Host
+	} else {
+		host = currentState.PodIP
+	}
+
+	return host, port, params.Path, nil
+}
+
+// Formats a URL from args.  For testability.
+func formatURL(host string, port int, path string) string {
+	return fmt.Sprintf("http://%s:%d%s", host, port, path)
+}
+
+// If the HTTP response code is successful (i.e. 400 > code >= 200), it returns Healthy.
+// If the HTTP response code is unsuccessful, it returns Unhealthy.
+// It returns Unknown and err if the HTTP communication itself fails.
+func DoHTTPCheck(url string, client HTTPGetInterface) (Status, error) {
+	res, err := client.Get(url)
+	if err != nil {
+		return Unknown, err
+	}
+	defer res.Body.Close()
+	if res.StatusCode >= http.StatusOK && res.StatusCode < http.StatusBadRequest {
+		return Healthy, nil
+	}
+	glog.V(1).Infof("Health check failed for %s, Response: %v", url, *res)
+	return Unhealthy, nil
+}
+
+// HealthCheck checks if the container is healthy by trying sending HTTP Get requests to the container.
+func (h *HTTPHealthChecker) HealthCheck(currentState api.PodState, container api.Container) (Status, error) {
+	host, port, path, err := getURLParts(currentState, container)
+	if err != nil {
+		return Unknown, err
+	}
+	return DoHTTPCheck(formatURL(host, port, path), h.client)
+}