Simple groupcache example

groupcache.go

// Simple groupcache example: https://github.com/golang/groupcache
// Running 3 instances:
// go run groupcache.go -addr=:8080 -pool=http://127.0.0.1:8080,http://127.0.0.1:8081,http://127.0.0.1:8082
// go run groupcache.go -addr=:8081 -pool=http://127.0.0.1:8081,http://127.0.0.1:8080,http://127.0.0.1:8082
// go run groupcache.go -addr=:8082 -pool=http://127.0.0.1:8082,http://127.0.0.1:8080,http://127.0.0.1:8081
// Testing:
// curl localhost:8080/color?name=red
package main

import (
	"errors"
	"flag"
	"log"
	"net/http"
	"strings"

	"github.com/golang/groupcache"
)

var Store = map[string][]byte{
	"red":   []byte("#FF0000"),
	"green": []byte("#00FF00"),
	"blue":  []byte("#0000FF"),
}

var Group = groupcache.NewGroup("foobar", 64<<20, groupcache.GetterFunc(
	func(ctx groupcache.Context, key string, dest groupcache.Sink) error {
		log.Println("looking up", key)
		v, ok := Store[key]
		if !ok {
			return errors.New("color not found")
		}
		dest.SetBytes(v)
		return nil
	},
))

func main() {
	addr := flag.String("addr", ":8080", "server address")
	peers := flag.String("pool", "http://localhost:8080", "server pool list")
	flag.Parse()
	http.HandleFunc("/color", func(w http.ResponseWriter, r *http.Request) {
		color := r.FormValue("name")
		var b []byte
		err := Group.Get(nil, color, groupcache.AllocatingByteSliceSink(&b))
		if err != nil {
			http.Error(w, err.Error(), http.StatusNotFound)
			return
		}
		w.Write(b)
		w.Write([]byte{'\n'})
	})
	p := strings.Split(*peers, ",")
	pool := groupcache.NewHTTPPool(p[0])
	pool.Set(p...)
	http.ListenAndServe(*addr, nil)
}

What do the handler of /color mean, Do remote groupcahes will request the path for data? Or just a path for debuging?

not bad Fiori, not bad :)

the unfortunate thing about groupcache is that they're not willing to evolve it. I personally think there should be a default cache store which is just an in-memory lru .. that same in-memory lru that they use to actually cache results is what I'd like to use to store my app cacheable data, and not have to have one allocation for my store then group cache with its own allocation of the same data

Sorry, but you could explain a bit more about what you mean? Why do you want to do this?

HI.. I am unable to get the github.com/golang/groupcache.
How to get ?

You probably need to update to accommodate golang/groupcache#131. make use of the standard library's context.Context.

line 45 should pass context.TODO() instead of nil, or it will panic on modern compilers.

Can we fetch the current set of peers in the pool if we are setting up peers dynamically