viper配置框架的介绍支持zookeeper的读取和监听
作者:Go语言中文网
viper作为配置框架,其功能非常的强大,我们没有理由不去了解一下。我们先看官网对它的功能简介:
viper是完整配置解决方案,他可以处理所有类型和格式的配置文件,他有如下功能:
- 设置默认配置
- 支持读取 JSON TOML YAML HCL 和 Java 属性配置文件
- 监听配置文件变化,实时读取读取配置文件内容
- 读取环境变量值
- 读取远程配置系统 (etcd Consul) 和监控配置变化
- 读取命令 Flag 值
- 读取 buffer 值
- 读取确切值
乍一看,未免有相见恨晚之感,可仔细一想,不免脑袋里有另外一种声音:不会不支持读取 zookeeper
吧?好吧,至少我是这样的。
基于这种想法,当然要去立马尝试,如下:
viper.AddRemoteProvider("zookeeper", "xx.xx.xx.xx:2181", "/viper/test")
返回结果是:
Unsupported Remote Provider Type zookeeper
果不其然,于是追踪 viper.AddRemoteProvider
的源码,发现viper只支持如下几种
var SupportedRemoteProviders = []string{"etcd", "consul", "firestore"}
如果就此打住,未免有点太可惜,作为偏执狂,总想着能否来改造下viper,让其支持 zookeeper
,于是在issue上找是否有人遇到同样的问题,还整让我找到了, 传送 。但是不完整,且稍微有点bug。所以根据他的基础上,我做了些调整。进入正题,我们开始修改viper源码。说明下,我的viper版本是最新的 1.7.0
修改源码
1、添加zookeeper.go
添加的位置: github.com/bketelsen/crypt/zookeeper
, zookeeper
目录需要自己创建, github.com/bketelsen/crypt
是viper的依赖包,会自动下载
文件内容:
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 }
这个文件是实现 ConfigManager
接口,我们在上图中看到 etcd
, consul
, filestore
,均有实现该接口,接口的定义很简单
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
,如下图
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) }
这两个方法是初始化 ConfigManager
对象,也就是我们刚才添加的 zookeeper.go
文件的对象
3、修改remote.go
文件的位置: github.com/spf13/viper/remote/remote.go
,如下图
找到74行,用下面的代码替换 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 }
细心的读者可能已经发现,其实就添加了两个case选项:
4、修改viper.go
文件的位置: github.com/spf13/viper/viper.go
,如下图
取+监听zookeeper(1)\image-20200521222843002.png)
找到两个 SupportedRemoteProviders
定义的定法,1.7.0版本的行号分别是:290,331。只要添加 zookeeper
,即可
SupportedRemoteProviders = []string{"etcd", "consul", "firestore", "zookeeper"}
好了,修改代码的工作已经完了,接下来我们来测试:
测试
注意:zookeeper中已经设置了内容
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("从zookeeper读取配置内容:%+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("从zookeeper读取更新内容:appName=%s,nodes=%+v\n", viper.Get("appName"), viper.Get("nodes")) } }() }
输出内容:
从zookeeper读取配置内容:{AppName:test Nodes:[127.0.0.1 127.0.0.2 127.0.0.3]}
从zookeeper读取更新内容:appName=test,nodes=[127.0.0.1 127.0.0.2 127.0.0.3]
如果我们修改zookeeper的内容,则viper会读取到更新后的内容:
set /viper/test {"appName":"test","nodes":["127.0.0.1","127.0.0.2","127.0.0.3","127.0.0.4"]}
从zookeeper读取更新内容:appName=test,nodes=[127.0.0.1 127.0.0.2 127.0.0.3 127.0.0.4]
结语
让viper支持 zookeeper
并不复杂的,并且基本上不需要修改原有的方法, 这要归结于viper用到一个非常重要的设计原则: 开闭原则 ,读者可以自行体会。
关于viper的基本使用, github 已经有非常详细的例子,这里就不再赘述,如有疑问,可以私信我
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