132 lines
3.9 KiB
Go
132 lines
3.9 KiB
Go
/*
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Copyright 2014 Google Inc. All rights reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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// Reads the configuration from the file. Example file for two services [nodejs & mysql]
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//{"Services": [
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// {
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// "Name":"nodejs",
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// "Port":10000,
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// "Endpoints":["10.240.180.168:8000", "10.240.254.199:8000", "10.240.62.150:8000"]
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// },
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// {
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// "Name":"mysql",
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// "Port":10001,
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// "Endpoints":["10.240.180.168:9000", "10.240.254.199:9000", "10.240.62.150:9000"]
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// }
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//]
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//}
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package config
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import (
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"bytes"
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"encoding/json"
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"fmt"
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"io/ioutil"
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"reflect"
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"time"
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"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
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"github.com/golang/glog"
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)
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// serviceConfig is a deserialized form of the config file format which ConfigSourceFile accepts.
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// TODO: this is apparently untested; is it used?
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type serviceConfig struct {
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Services []struct {
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Name string `json: "name"`
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Port int `json: "port"`
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Endpoints []string `json: "endpoints"`
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} `json:"service"`
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}
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// ConfigSourceFile periodically reads service configurations in JSON from a file, and sends the services and endpoints defined in the file to the specified channels.
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type ConfigSourceFile struct {
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serviceChannel chan ServiceUpdate
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endpointsChannel chan EndpointsUpdate
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filename string
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}
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// NewConfigSourceFile creates a new ConfigSourceFile and let it immediately runs the created ConfigSourceFile in a goroutine.
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func NewConfigSourceFile(filename string, serviceChannel chan ServiceUpdate, endpointsChannel chan EndpointsUpdate) ConfigSourceFile {
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config := ConfigSourceFile{
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filename: filename,
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serviceChannel: serviceChannel,
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endpointsChannel: endpointsChannel,
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}
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go config.Run()
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return config
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}
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// Run begins watching the config file.
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func (s ConfigSourceFile) Run() {
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glog.V(1).Infof("Watching file %s", s.filename)
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var lastData []byte
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var lastServices []api.Service
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var lastEndpoints []api.Endpoints
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sleep := 5 * time.Second
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// Used to avoid spamming the error log file, makes error logging edge triggered.
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hadSuccess := true
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for {
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data, err := ioutil.ReadFile(s.filename)
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if err != nil {
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msg := fmt.Sprintf("Couldn't read file: %s : %v", s.filename, err)
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if hadSuccess {
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glog.Error(msg)
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} else {
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glog.V(1).Info(msg)
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}
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hadSuccess = false
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time.Sleep(sleep)
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continue
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}
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hadSuccess = true
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if bytes.Equal(lastData, data) {
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time.Sleep(sleep)
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continue
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}
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lastData = data
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config := &serviceConfig{}
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if err = json.Unmarshal(data, config); err != nil {
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glog.Errorf("Couldn't unmarshal configuration from file : %s %v", data, err)
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continue
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}
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// Ok, we have a valid configuration, send to channel for
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// rejiggering.
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newServices := make([]api.Service, len(config.Services))
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newEndpoints := make([]api.Endpoints, len(config.Services))
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for i, service := range config.Services {
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newServices[i] = api.Service{TypeMeta: api.TypeMeta{ID: service.Name}, Port: service.Port}
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newEndpoints[i] = api.Endpoints{TypeMeta: api.TypeMeta{ID: service.Name}, Endpoints: service.Endpoints}
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}
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if !reflect.DeepEqual(lastServices, newServices) {
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serviceUpdate := ServiceUpdate{Op: SET, Services: newServices}
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s.serviceChannel <- serviceUpdate
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lastServices = newServices
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}
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if !reflect.DeepEqual(lastEndpoints, newEndpoints) {
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endpointsUpdate := EndpointsUpdate{Op: SET, Endpoints: newEndpoints}
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s.endpointsChannel <- endpointsUpdate
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lastEndpoints = newEndpoints
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}
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time.Sleep(sleep)
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}
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}
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