create pkg/probe as successor to pkg/health.

pkg/probe/http/http.go

@@ -0,0 +1,67 @@
+/*
+Copyright 2015 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 http
+
+import (
+	"net"
+	"net/http"
+	"net/url"
+	"strconv"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/probe"
+
+	"github.com/golang/glog"
+)
+
+var client = &http.Client{}
+
+// Probe returns a ProbeRunner capable of running an http check.
+func Probe(host string, port int, path string) (probe.Status, error) {
+	return DoHTTPProbe(formatURL(host, port, path), client)
+}
+
+type HTTPGetInterface interface {
+	Get(u string) (*http.Response, error)
+}
+
+// DoHTTPProbe checks if a GET request to the url succeeds.
+// If the HTTP response code is successful (i.e. 400 > code >= 200), it returns Healthy.
+// If the HTTP response code is unsuccessful or HTTP communication fails, it returns Unhealthy.
+// This is exported because some other packages may want to do direct HTTP probes.
+func DoHTTPProbe(url string, client HTTPGetInterface) (probe.Status, error) {
+	res, err := client.Get(url)
+	if err != nil {
+		glog.V(1).Infof("HTTP probe error: %v", err)
+		return probe.Unhealthy, nil
+	}
+	defer res.Body.Close()
+	if res.StatusCode >= http.StatusOK && res.StatusCode < http.StatusBadRequest {
+		return probe.Healthy, nil
+	}
+	glog.V(1).Infof("Health check failed for %s, Response: %v", url, *res)
+	return probe.Unhealthy, nil
+}
+
+// formatURL formats a URL from args.  For testability.
+func formatURL(host string, port int, path string) string {
+	u := url.URL{
+		Scheme: "http",
+		Host:   net.JoinHostPort(host, strconv.Itoa(port)),
+		Path:   path,
+	}
+	return u.String()
+}