viper配置框架的介绍支持zookeeper的读取和监听

    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 etcdconsulfilestore ,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

     

    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)
    }

    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

    到此这篇关于viper配置框架的介绍支持zookeeper的读取和监听的文章就介绍到这了,更多相关viper配置框架支持zookeeper的读取和监听内容请搜索lingkb以前的文章或继续浏览下面的相关文章希望大家以后多多支持lingkb!