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 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, 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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