Code change:
It's not well tested nor widely used; so it should either be removed or have tests and uses .

Related discussion:
text: <del> /* 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. */ // Reads the configuration from the file. Example file for two services [nodejs & mysql] //{"Services": [ //   { //      "Name":"nodejs", //      "Port":10000, //      "Endpoints":["10.240.180.168:8000", "10.240.254.199:8000", "10.240.62.150:8000"] //   }, //   { //      "Name":"mysql", //      "Port":10001, //      "Endpoints":["10.240.180.168:9000", "10.240.254.199:9000", "10.240.62.150:9000"] //   } //] //} package config import ( "bytes" "encoding/json" "fmt" "io/ioutil" "reflect" "time" "github.com/GoogleCloudPlatform/kubernetes/pkg/api" "github.com/golang/glog" ) // serviceConfig is a deserialized form of the config file format which ConfigSourceFile accepts. // TODO: this is apparently untested; is it used? type serviceConfig struct { Services []struct { Name      string   `json: "name"` Port      int      `json: "port"` Endpoints []string `json: "endpoints"` } `json:"service"` } // ConfigSourceFile periodically reads service configurations in JSON from a file, and sends the services and endpoints defined in the file to the specified channels. type ConfigSourceFile struct { serviceChannel   chan ServiceUpdate endpointsChannel chan EndpointsUpdate filename         string } // NewConfigSourceFile creates a new ConfigSourceFile and let it immediately runs the created ConfigSourceFile in a goroutine. func NewConfigSourceFile(filename string, serviceChannel chan ServiceUpdate, endpointsChannel chan EndpointsUpdate) ConfigSourceFile { config := ConfigSourceFile{ filename:         filename, serviceChannel:   serviceChannel, endpointsChannel: endpointsChannel, } go config.Run() return config } // Run begins watching the config file. func (s ConfigSourceFile) Run() { glog.V(1).Infof("Watching file %s", s.filename) var lastData []byte var lastServices []api.Service var lastEndpoints []api.Endpoints sleep := 5 * time.Second // Used to avoid spamming the error log file, makes error logging edge triggered. hadSuccess := true for { data, err := ioutil.ReadFile(s.filename) if err != nil { msg := fmt.Sprintf("Couldn't read file: %s : %v", s.filename, err) if hadSuccess { glog.Error(msg) } else { glog.V(1).Info(msg) } hadSuccess = false time.Sleep(sleep) continue } hadSuccess = true if bytes.Equal(lastData, data) { time.Sleep(sleep) continue } lastData = data config := &serviceConfig{} if err = json.Unmarshal(data, config); err != nil { glog.Errorf("Couldn't unmarshal configuration from file : %s %v", data, err) continue } // Ok, we have a valid configuration, send to channel for // rejiggering. newServices := make([]api.Service, len(config.Services)) newEndpoints := make([]api.Endpoints, len(config.Services)) for i, service := range config.Services { newServices[i] = api.Service{TypeMeta: api.TypeMeta{ID: service.Name}, Port: service.Port} newEndpoints[i] = api.Endpoints{TypeMeta: api.TypeMeta{ID: service.Name}, Endpoints: service.Endpoints} } if !reflect.DeepEqual(lastServices, newServices) { serviceUpdate := ServiceUpdate{Op: SET, Services: newServices} s.serviceChannel <- serviceUpdate lastServices = newServices } if !reflect.DeepEqual(lastEndpoints, newEndpoints) { endpointsUpdate := EndpointsUpdate{Op: SET, Endpoints: newEndpoints} s.endpointsChannel <- endpointsUpdate lastEndpoints = newEndpoints } time.Sleep(sleep) } } </del>