Extract EtcdHelper interface

pkg/tools/etcd_util.go

@@ -0,0 +1,121 @@
+/*
+Copyright 2015 The Kubernetes Authors 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 tools
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"os/exec"
+
+	"github.com/coreos/go-etcd/etcd"
+
+	"github.com/golang/glog"
+)
+
+// IsEtcdNotFound returns true iff err is an etcd not found error.
+func IsEtcdNotFound(err error) bool {
+	return isEtcdErrorNum(err, EtcdErrorCodeNotFound)
+}
+
+// IsEtcdNodeExist returns true iff err is an etcd node aleady exist error.
+func IsEtcdNodeExist(err error) bool {
+	return isEtcdErrorNum(err, EtcdErrorCodeNodeExist)
+}
+
+// IsEtcdTestFailed returns true iff err is an etcd write conflict.
+func IsEtcdTestFailed(err error) bool {
+	return isEtcdErrorNum(err, EtcdErrorCodeTestFailed)
+}
+
+// IsEtcdWatchStoppedByUser returns true iff err is a client triggered stop.
+func IsEtcdWatchStoppedByUser(err error) bool {
+	return etcd.ErrWatchStoppedByUser == err
+}
+
+// isEtcdErrorNum returns true iff err is an etcd error, whose errorCode matches errorCode
+func isEtcdErrorNum(err error, errorCode int) bool {
+	etcdError, ok := err.(*etcd.EtcdError)
+	return ok && etcdError != nil && etcdError.ErrorCode == errorCode
+}
+
+// etcdErrorIndex returns the index associated with the error message and whether the
+// index was available.
+func etcdErrorIndex(err error) (uint64, bool) {
+	if etcdError, ok := err.(*etcd.EtcdError); ok {
+		return etcdError.Index, true
+	}
+	return 0, false
+}
+
+// GetEtcdVersion performs a version check against the provided Etcd server,
+// returning the string response, and error (if any).
+func GetEtcdVersion(host string) (string, error) {
+	response, err := http.Get(host + "/version")
+	if err != nil {
+		return "", err
+	}
+	defer response.Body.Close()
+	if response.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("unsuccessful response from etcd server %q: %v", host, err)
+	}
+	versionBytes, err := ioutil.ReadAll(response.Body)
+	if err != nil {
+		return "", err
+	}
+	return string(versionBytes), nil
+}
+
+func startEtcd() (*exec.Cmd, error) {
+	cmd := exec.Command("etcd")
+	err := cmd.Start()
+	if err != nil {
+		return nil, err
+	}
+	return cmd, nil
+}
+
+func NewEtcdClientStartServerIfNecessary(server string) (EtcdClient, error) {
+	_, err := GetEtcdVersion(server)
+	if err != nil {
+		glog.Infof("Failed to find etcd, attempting to start.")
+		_, err := startEtcd()
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	servers := []string{server}
+	return etcd.NewClient(servers), nil
+}
+
+type etcdHealth struct {
+	// Note this has to be public so the json library can modify it.
+	Health string `json:health`
+}
+
+func EtcdHealthCheck(data []byte) error {
+	obj := etcdHealth{}
+	if err := json.Unmarshal(data, &obj); err != nil {
+		return err
+	}
+	if obj.Health != "true" {
+		return fmt.Errorf("Unhealthy status: %s", obj.Health)
+	}
+	return nil
+}