Add a validator for validating components in the cluster infrastructure.

pkg/apiserver/validator.go

@@ -0,0 +1,122 @@
+/*
+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 apiserver
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net"
+	"net/http"
+	"strconv"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/health"
+)
+
+// TODO: this basic interface is duplicated in N places.  consolidate?
+type httpGet interface {
+	Get(url string) (*http.Response, error)
+}
+
+type server struct {
+	addr string
+	port int
+}
+
+// validator is responsible for validating the cluster and serving
+type validator struct {
+	// a list of servers to health check
+	servers map[string]server
+	client  httpGet
+}
+
+func (s *server) check(client httpGet) (health.Status, string, error) {
+	resp, err := client.Get("http://" + net.JoinHostPort(s.addr, strconv.Itoa(s.port)) + "/healthz")
+	if err != nil {
+		return health.Unknown, "", err
+	}
+	defer resp.Body.Close()
+	data, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return health.Unknown, string(data), err
+	}
+	if resp.StatusCode != http.StatusOK {
+		return health.Unhealthy, string(data),
+			fmt.Errorf("unhealthy http status code: %d (%s)", resp.StatusCode, resp.Status)
+	}
+	return health.Healthy, string(data), nil
+}
+
+type ServerStatus struct {
+	Component  string        `json:"component,omitempty"`
+	Health     string        `json:"health,omitempty"`
+	HealthCode health.Status `json:"healthCode,omitempty"`
+	Msg        string        `json:"msg,omitempty"`
+	Err        string        `json:"err,omitempty"`
+}
+
+func (v *validator) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	reply := []ServerStatus{}
+	for name, server := range v.servers {
+		status, msg, err := server.check(v.client)
+		var errorMsg string
+		if err != nil {
+			errorMsg = err.Error()
+		} else {
+			errorMsg = "nil"
+		}
+		reply = append(reply, ServerStatus{name, status.String(), status, msg, errorMsg})
+	}
+	data, err := json.Marshal(reply)
+	log.Printf("FOO: %s", string(data))
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte(err.Error()))
+		return
+	}
+	w.WriteHeader(http.StatusOK)
+	w.Write(data)
+}
+
+// NewValidator creates a validator for a set of servers.
+func NewValidator(servers map[string]string) (http.Handler, error) {
+	result := map[string]server{}
+	for name, value := range servers {
+		host, port, err := net.SplitHostPort(value)
+		if err != nil {
+			return nil, fmt.Errorf("invalid server spec: %s (%v)", value, err)
+		}
+		val, err := strconv.Atoi(port)
+		if err != nil {
+			return nil, fmt.Errorf("invalid server spec: %s (%v)", port, err)
+		}
+		result[name] = server{host, val}
+	}
+	return &validator{
+		servers: result,
+		client:  &http.Client{},
+	}, nil
+}
+
+func makeTestValidator(servers map[string]string, get httpGet) (http.Handler, error) {
+	v, e := NewValidator(servers)
+	if e == nil {
+		v.(*validator).client = get
+	}
+	return v, e
+}