groupcache‎ で組み込み型分散キャッシュ ref: http://qiita.com/yosisa/items/4980559f328fb31c3a8d

file0.go

package main

import (
    "encoding/json"
    "github.com/codegangsta/martini"
    "github.com/golang/groupcache"
    "net/http"
    "os"
    "time"
)

func main() {
    addr := os.Getenv("GROUPCACHE_ADDR")
    peers := groupcache.NewHTTPPool("http://" + addr)
    peers.Set("http://127.0.0.1:8000", "http://127.0.0.1:8001")
    go http.ListenAndServe(addr, peers)
    heavy := groupcache.NewGroup("heavy", 64<<20, groupcache.GetterFunc(heavyTask))

    m := martini.Classic()
    m.Get("/_stats", func() []byte {
        v, err := json.Marshal(&heavy.Stats)
        if err != nil {
            panic(err)
        }
        return v
    })
    m.Get("/:key", func(params martini.Params) string {
        var result string
        if err := heavy.Get(nil, params["key"], groupcache.StringSink(&result)); err != nil {
            panic(err)
        }
        return result
    })
    m.Run()
}

func heavyTask(ctx groupcache.Context, key string, dst groupcache.Sink) error {
    time.Sleep(400 * time.Millisecond)
    dst.SetString("Value of " + key)
    return nil
}

file1.txt

$ GROUPCACHE_ADDR=127.0.0.1:8000 go run main.go
$ GROUPCACHE_ADDR=127.0.0.1:8001 PORT=3001 go run main.go

file2.txt

$ curl localhost:3000/foo  # 400ms
$ curl localhost:3001/foo  # <1ms

Nice demo.