| /* |
| Copyright 2017 The Kubernetes Authors. |
| |
| 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 preflight |
| |
| import ( |
| "fmt" |
| "math/rand" |
| "net" |
| "net/url" |
| "time" |
| ) |
| |
| const connectionTimeout = 1 * time.Second |
| |
| // EtcdConnection holds the Etcd server list |
| type EtcdConnection struct { |
| ServerList []string |
| } |
| |
| func (EtcdConnection) serverReachable(connURL *url.URL) bool { |
| scheme := connURL.Scheme |
| if scheme == "http" || scheme == "https" || scheme == "tcp" { |
| scheme = "tcp" |
| } |
| if conn, err := net.DialTimeout(scheme, connURL.Host, connectionTimeout); err == nil { |
| defer conn.Close() |
| return true |
| } |
| return false |
| } |
| |
| func parseServerURI(serverURI string) (*url.URL, error) { |
| connURL, err := url.Parse(serverURI) |
| if err != nil { |
| return &url.URL{}, fmt.Errorf("unable to parse etcd url: %v", err) |
| } |
| return connURL, nil |
| } |
| |
| // CheckEtcdServers will attempt to reach all etcd servers once. If any |
| // can be reached, return true. |
| func (con EtcdConnection) CheckEtcdServers() (done bool, err error) { |
| // Attempt to reach every Etcd server randomly. |
| serverNumber := len(con.ServerList) |
| serverPerms := rand.Perm(serverNumber) |
| for _, index := range serverPerms { |
| host, err := parseServerURI(con.ServerList[index]) |
| if err != nil { |
| return false, err |
| } |
| if con.serverReachable(host) { |
| return true, nil |
| } |
| } |
| return false, nil |
| } |