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Forked from fiorix/groupcache.go
Created October 9, 2018 20:58
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Simple groupcache example
// 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)
}
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