viper配置框架的介紹支持zookeeper的讀取和監(jiān)聽
viper作為配置框架,其功能非常的強大,我們沒有理由不去了解一下。我們先看官網(wǎng)對它的功能簡介:
viper是完整配置解決方案,他可以處理所有類型和格式的配置文件,他有如下功能:
- 設置默認配置
- 支持讀取 JSON TOML YAML HCL 和 Java 屬性配置文件
- 監(jiān)聽配置文件變化,實時讀取讀取配置文件內容
- 讀取環(huán)境變量值
- 讀取遠程配置系統(tǒng) (etcd Consul) 和監(jiān)控配置變化
- 讀取命令 Flag 值
- 讀取 buffer 值
- 讀取確切值
乍一看,未免有相見恨晚之感,可仔細一想,不免腦袋里有另外一種聲音:不會不支持讀取 zookeeper
吧?好吧,至少我是這樣的。
基于這種想法,當然要去立馬嘗試,如下:
viper.AddRemoteProvider("zookeeper", "xx.xx.xx.xx:2181", "/viper/test")
返回結果是:
Unsupported Remote Provider Type zookeeper
果不其然,于是追蹤 viper.AddRemoteProvider
的源碼,發(fā)現(xiàn)viper只支持如下幾種
var SupportedRemoteProviders = []string{"etcd", "consul", "firestore"}
如果就此打住,未免有點太可惜,作為偏執(zhí)狂,總想著能否來改造下viper,讓其支持 zookeeper
,于是在issue上找是否有人遇到同樣的問題,還整讓我找到了, 傳送 。但是不完整,且稍微有點bug。所以根據(jù)他的基礎上,我做了些調整。進入正題,我們開始修改viper源碼。說明下,我的viper版本是最新的 1.7.0
修改源碼
1、添加zookeeper.go
添加的位置: github.com/bketelsen/crypt/zookeeper
, zookeeper
目錄需要自己創(chuàng)建, github.com/bketelsen/crypt
是viper的依賴包,會自動下載
文件內容:
package zookeeper import ( "errors" "fmt" zk "github.com/samuel/go-zookeeper/zk" //"github.com/xordataexchange/crypt/backend" "github.com/bketelsen/crypt/backend" "strings" "time" ) type Client struct { client *zk.Conn waitIndex uint64 } func New(machines []string) (*Client, error) { zkclient, _, err := zk.Connect(machines, time.Second) if err != nil { return nil, err } return &Client{zkclient, 0}, nil } func (c *Client) Get(key string) ([]byte, error) { resp, _, err := c.client.Get(key) if err != nil { return nil, err } return []byte(resp), nil } func nodeWalk(prefix string, c *Client, vars map[string]string) error { l, stat, err := c.client.Children(prefix) if err != nil { return err } if stat.NumChildren == 0 { b, _, err := c.client.Get(prefix) if err != nil { return err } vars[prefix] = string(b) } else { for _, key := range l { s := prefix + "/" + key _, stat, err := c.client.Exists(s) if err != nil { return err } if stat.NumChildren == 0 { b, _, err := c.client.Get(s) if err != nil { return err } vars[s] = string(b) } else { nodeWalk(s, c, vars) } } } return nil } func (c *Client) GetValues(key string, keys []string) (map[string]string, error) { vars := make(map[string]string) for _, v := range keys { v = fmt.Sprintf("%s/%s", key, v) v = strings.Replace(v, "/*", "", -1) _, _, err := c.client.Exists(v) if err != nil { return vars, err } if v == "/" { v = "" } err = nodeWalk(v, c, vars) if err != nil { return vars, err } } return vars, nil } func (c *Client) List(key string) (backend.KVPairs, error) { var list backend.KVPairs resp, stat, err := c.client.Children(key) if err != nil { return nil, err } if stat.NumChildren == 0 { return list, nil } entries, err := c.GetValues(key, resp) if err != nil { return nil, err } for k, v := range entries { list = append(list, &backend.KVPair{Key: k, Value: []byte(v)}) } return list, nil } func (c *Client) createParents(key string) error { flags := int32(0) acl := zk.WorldACL(zk.PermAll) if key[0] != '/' { return errors.New("Invalid path") } payload := []byte("") pathString := "" pathNodes := strings.Split(key, "/") for i := 1; i < len(pathNodes); i++ { pathString += "/" + pathNodes[i] _, err := c.client.Create(pathString, payload, flags, acl) // not being able to create the node because it exists or not having // sufficient rights is not an issue. It is ok for the node to already // exist and/or us to only have read rights if err != nil && err != zk.ErrNodeExists && err != zk.ErrNoAuth { return err } } return nil } func (c *Client) Set(key string, value []byte) error { err := c.createParents(key) if err != nil { return err } _, err = c.client.Set(key, []byte(value), -1) return err } func (c *Client) Watch(key string, stop chan bool) <-chan *backend.Response { respChan := make(chan *backend.Response, 0) go func() { for { resp, _, watch, err := c.client.GetW(key) if err != nil { respChan <- &backend.Response{nil, err} time.Sleep(time.Second * 5) } select { case e := <-watch: if e.Type == zk.EventNodeDataChanged { resp, _, err = c.client.Get(key) if err != nil { respChan <- &backend.Response{nil, err} } c.waitIndex = 0 respChan <- &backend.Response{[]byte(resp), nil} } } } }() return respChan }
這個文件是實現(xiàn) ConfigManager
接口,我們在上圖中看到 etcd
, consul
, filestore
,均有實現(xiàn)該接口,接口的定義很簡單
type ConfigManager interface { Get(key string) ([]byte, error) List(key string) (KVPairs, error) Set(key string, value []byte) error Watch(key string, stop chan bool) <-chan *Response }
2、修改config.go
文件的位置: github.com/bketelsen/crypt/config/config.go
,如下圖
在 func NewStandardEtcdConfigManager(machines []string) (ConfigManager, error)
方法下面添加如下方法:
// NewStandardZookeeperConfigManager returns a new ConfigManager backed by Zookeeper. // Data will be encrypted. func NewStandardZookeeperConfigManager(machines []string) (ConfigManager, error) { store, err := zookeeper.New(machines) if err != nil { return nil, err } return NewStandardConfigManager(store) }
在 func NewEtcdConfigManager(machines []string, keystore io.Reader) (ConfigManager, error)
方法下面添加如下方法:
// NewZookeeperConfigManager returns a new ConfigManager backed by zookeeper. // Data will be encrypted. func NewZookeeperConfigManager(machines []string, keystore io.Reader) (ConfigManager, error) { store, err := zookeeper.New(machines) if err != nil { return nil, err } return NewConfigManager(store, keystore) }
這兩個方法是初始化 ConfigManager
對象,也就是我們剛才添加的 zookeeper.go
文件的對象
3、修改remote.go
文件的位置: github.com/spf13/viper/remote/remote.go
,如下圖
找到74行,用下面的代碼替換 func getConfigManager(rp viper.RemoteProvider) (crypt.ConfigManager, error)
方法
func getConfigManager(rp viper.RemoteProvider) (crypt.ConfigManager, error) { var cm crypt.ConfigManager var err error if rp.SecretKeyring() != "" { var kr *os.File kr, err = os.Open(rp.SecretKeyring()) if err != nil { return nil, err } defer kr.Close() switch rp.Provider() { case "etcd": cm, err = crypt.NewEtcdConfigManager([]string{rp.Endpoint()}, kr) case "zookeeper": cm, err = crypt.NewZookeeperConfigManager([]string{rp.Endpoint()}, kr) case "firestore": cm, err = crypt.NewFirestoreConfigManager([]string{rp.Endpoint()}, kr) default: cm, err = crypt.NewConsulConfigManager([]string{rp.Endpoint()}, kr) } } else { switch rp.Provider() { case "etcd": cm, err = crypt.NewStandardEtcdConfigManager([]string{rp.Endpoint()}) case "zookeeper": cm, err = crypt.NewStandardZookeeperConfigManager([]string{rp.Endpoint()}) case "firestore": cm, err = crypt.NewStandardFirestoreConfigManager([]string{rp.Endpoint()}) default: cm, err = crypt.NewStandardConsulConfigManager([]string{rp.Endpoint()}) } } if err != nil { return nil, err } return cm, nil }
細心的讀者可能已經(jīng)發(fā)現(xiàn),其實就添加了兩個case選項:
4、修改viper.go
文件的位置: github.com/spf13/viper/viper.go
,如下圖
取+監(jiān)聽zookeeper(1)\image-20200521222843002.png)
找到兩個 SupportedRemoteProviders
定義的定法,1.7.0版本的行號分別是:290,331。只要添加 zookeeper
,即可
SupportedRemoteProviders = []string{"etcd", "consul", "firestore", "zookeeper"}
好了,修改代碼的工作已經(jīng)完了,接下來我們來測試:
測試
注意:zookeeper中已經(jīng)設置了內容
set /viper/test {"appName":"test","nodes":["127.0.0.1","127.0.0.2","127.0.0.3"]}
package main import ( "fmt" "github.com/fsnotify/fsnotify" "github.com/spf13/viper" _ "github.com/spf13/viper/remote" "time" ) type config struct { AppName string Nodes []string } func main() { var waitGroup=sync.WaitGroup{} waitGroup.Add(1) readRemoteZookeeper() go watchRemoteZookeeper() waitGroup.Wait() } func readRemoteZookeeper() { viper.AddRemoteProvider("zookeeper", "62.234.15.24:2181", "/viper/test") viper.SetConfigType("json") err := viper.ReadRemoteConfig() if err != nil { panic(fmt.Sprintf("read remote zookeeper error:+%v", err)) } var C config viper.Unmarshal(&C) fmt.Printf("從zookeeper讀取配置內容:%+v\n", C) } func watchRemoteZookeeper() { go func() { for { //delay after each request time.Sleep(time.Second * 5) err := viper.WatchRemoteConfig() if err != nil { fmt.Errorf("unable to read remote config: %v", err) continue } fmt.Printf("從zookeeper讀取更新內容:appName=%s,nodes=%+v\n", viper.Get("appName"), viper.Get("nodes")) } }() }
輸出內容:
從zookeeper讀取配置內容:{AppName:test Nodes:[127.0.0.1 127.0.0.2 127.0.0.3]}
從zookeeper讀取更新內容:appName=test,nodes=[127.0.0.1 127.0.0.2 127.0.0.3]
如果我們修改zookeeper的內容,則viper會讀取到更新后的內容:
set /viper/test {"appName":"test","nodes":["127.0.0.1","127.0.0.2","127.0.0.3","127.0.0.4"]}
從zookeeper讀取更新內容:appName=test,nodes=[127.0.0.1 127.0.0.2 127.0.0.3 127.0.0.4]
結語
讓viper支持 zookeeper
并不復雜的,并且基本上不需要修改原有的方法, 這要歸結于viper用到一個非常重要的設計原則: 開閉原則 ,讀者可以自行體會。
關于viper的基本使用, github 已經(jīng)有非常詳細的例子,這里就不再贅述,如有疑問,可以私信我
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