源码 kratos 配置热加载分析

源码 kratos 配置热加载分析

 github.com\go-kratos\kratos\v2@v2.1.2\config\value.go

 github.com/go-kratos/kratos/v2@v2.1.2/config/config.go:40

 通过go程开启监听文件变动的功能

package main

import (
   "fmt"
   "time"
)

func forever() {
   for {
      fmt.Println("forever", time.Now())
      time.Sleep(8 * time.Second)
   }
}
func main() {

   go forever()

   for {
      fmt.Println("main", time.Now())
      time.Sleep(4 * time.Second)

   }
}

c := config.New(
   config.WithSource(
      file.NewSource(flagconf),
   ),
)
defer c.Close()

if err := c.Load(); err != nil {
   panic(err)
}

func (c *config) Load() error {
   for _, src := range c.opts.sources {
      kvs, err := src.Load()
      if err != nil {
         return err
      }
      for _, v := range kvs {
         c.log.Infof("config loaded: %s format: %s", v.Key, v.Format)
      }
      if err = c.reader.Merge(kvs...); err != nil {
         c.log.Errorf("failed to merge config source: %v", err)
         return err
      }
      w, err := src.Watch()
      if err != nil {
         c.log.Errorf("failed to watch config source: %v", err)
         return err
      }
      c.watchers = append(c.watchers, w)
      go c.watch(w)
   }
   if err := c.reader.Resolve(); err != nil {
      c.log.Errorf("failed to resolve config source: %v", err)
      return err
   }
   return nil
}

func (c *config) watch(w Watcher) {
   for {
      kvs, err := w.Next()
      if errors.Is(err, context.Canceled) {
         c.log.Infof("watcher's ctx cancel : %v", err)
         return
}
      if err != nil {
         time.Sleep(time.Second)
         c.log.Errorf("failed to watch next config: %v", err)
         continue
}
      if err := c.reader.Merge(kvs...); err != nil {
         c.log.Errorf("failed to merge next config: %v", err)
         continue
}
      if err := c.reader.Resolve(); err != nil {
         c.log.Errorf("failed to resolve next config: %v", err)
         continue
}
      c.cached.Range(func(key, value interface{}) bool {
         k := key.(string)
         v := value.(Value)
         if n, ok := c.reader.Value(k); ok && !reflect.DeepEqual(n.Load(), v.Load()) {
            v.Store(n.Load())
            if o, ok := c.observers.Load(k); ok {
               o.(Observer)(k, v)
            }
         }
         return true
})
   }
}