Golang使用第三方包viper读取yaml配置信息操作

database:
 host: 127.0.0.1
 user: root
 dbname: test
 pwd: 123456

package main 
import (
 "fmt"
 "os" 
 "github.com/spf13/viper"
)
 
func main() {
 //获取项目的执行路径
 path, err := os.getwd()
 if err != nil {
 panic(err)
 }
 
 config := viper.new() 
 config.addconfigpath(path)  //设置读取的文件路径
 config.setconfigname("config") //设置读取的文件名
 config.setconfigtype("yaml") //设置文件的类型
 //尝试进行配置读取
 if err := config.readinconfig(); err != nil {
 panic(err)
 }
 
 //打印文件读取出来的内容:
 fmt.println(config.get("database.host"))
 fmt.println(config.get("database.user"))
 fmt.println(config.get("database.dbname"))
 fmt.println(config.get("database.pwd")) 
}

127.0.0.1
root
test
123456

viperinstance := viper.new() // viper实例
viperinstance.watchconfig()
viperinstance.onconfigchange(func(e fsnotify.event) {
 log.print("config file updated.")
 viperloadconf(viperinstance) // 加载配置的方法
})

func (v *viper) watchconfig() {
 go func() {
   // 建立新的监视处理程序，开启一个协程开始等待事件
   // 从i/o完成端口读取，将事件注入到event对象中：watcher.events
 watcher, err := fsnotify.newwatcher() 
 if err != nil {
 log.fatal(err)
 }
 defer watcher.close()
 
 // we have to watch the entire directory to pick up renames/atomic saves in a cross-platform way
 filename, err := v.getconfigfile() 
 if err != nil {
 log.println("error:", err)
 return
 }
 
 configfile := filepath.clean(filename)  //配置文件e:\etc\bizsvc\config.yml
 configdir, _ := filepath.split(configfile) // e:\etc\bizsvc\
 
 done := make(chan bool)
 go func() {
 for {
 select {
    // 读取的event对象有两个属性，name为e:\etc\bizsvc\config.yml，op为write（对文件的操作）
 case event := <-watcher.events:
 // 清除内部的..和他前面的元素，清除当前路径.，用来判断操作的文件是否是configfile
  if filepath.clean(event.name) == configfile {
    // 如果对该文件进行了创建操作或写操作
  if event.op&fsnotify.write == fsnotify.write || event.op&fsnotify.create == fsnotify.create {
  err := v.readinconfig()
  if err != nil {
  log.println("error:", err)
  }
  v.onconfigchange(event)
  }
  }
 case err := <-watcher.errors:
     // 有错误将打印
  log.println("error:", err)
 }
 }
 }() 
 watcher.add(configdir)
 <-done
 }()
}

type viper struct {
 // delimiter that separates a list of keys
 // used to access a nested value in one go
 keydelim string
 
 // a set of paths to look for the config file in
 configpaths []string
 
 // the filesystem to read config from.
 fs afero.fs
 
 // a set of remote providers to search for the configuration
 remoteproviders []*defaultremoteprovider
 
 // name of file to look for inside the path
 configname string
 configfile string
 configtype string
 envprefix string
 
 automaticenvapplied bool
 envkeyreplacer  *strings.replacer
 
 config   map[string]interface{}
 override  map[string]interface{}
 defaults  map[string]interface{}
 kvstore  map[string]interface{}
 pflags   map[string]flagvalue
 env   map[string]string
 aliases  map[string]string
 typebydefvalue bool
 
 // store read properties on the object so that we can write back in order with comments.
 // this will only be used if the configuration read is a properties file.
 properties *properties.properties
 
 onconfigchange func(fsnotify.event)
}

func (v *viper) onconfigchange(run func(in fsnotify.event)) {
 v.onconfigchange = run
}

 viperinstance.onconfigchange(func(e fsnotify.event) {
 log.print("config file updated.")
 viperloadconf(viperinstance) // viperloadconf函数就是将最新配置注入到自定义结构体对象的逻辑
 })