Discuss: https://groups.google.com/forum/#!topic/golang-nuts/-0-pblAKXr0 Code source: http://play.golang.org/p/usN4s5iUga

example_config.go

package main

import "fmt"
import "time"
import "sync"

//This datastructure never gets modified, only new ones created.
type Config struct {
	a string
	b string
}

var configMutex sync.Mutex
var globalconfig *Config = &Config{"foo", "bar"}

func fakeWatchForNewConfig() {
	i := 0
	j := 0
	for {
		time.Sleep(1 * time.Second)
		i += 1
		j += 1
		configMutex.Lock()
		globalconfig = &Config{fmt.Sprintf("foo%d", i), fmt.Sprintf("foo%d", j)}
		configMutex.Unlock()
	}
}

func SnapShotConfig() *Config {
	configMutex.Lock()
	ret := globalconfig
	configMutex.Unlock()
	return ret
}

func main() {
	go fakeWatchForNewConfig()

	for {
		//conf is safe because it is immutable.
		//the snapshot will never change, there are no data races.
		conf := SnapShotConfig()
		fmt.Println(conf.a, conf.b)
		time.Sleep(1 * time.Second)
	}

}