groupcache/cmd/server/main.go

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package main
import (
"context"
"flag"
"fmt"
"log"
"net/http"
"os"
"os/signal"
"strings"
"syscall"
"time"
"github.com/mailgun/groupcache/v2"
)
var store = map[string]string{}
var group = groupcache.NewGroup("cache1", 64<<20, groupcache.GetterFunc(
func(ctx context.Context, key string, dest groupcache.Sink) error {
fmt.Printf("Get Called\n")
v, ok := store[key]
if !ok {
return fmt.Errorf("key not set")
} else {
if err := dest.SetBytes([]byte(v), time.Now().Add(10*time.Minute)); err != nil {
log.Printf("Failed to set cache value for key '%s' - %v\n", key, err)
return err
}
}
return nil
},
))
func main() {
addr := flag.String("addr", ":8080", "server address")
addr2 := flag.String("api-addr", ":8081", "api server address")
peers := flag.String("pool", "http://localhost:8080", "server pool list")
flag.Parse()
p := strings.Split(*peers, ",")
pool := groupcache.NewHTTPPoolOpts(fmt.Sprintf("http://%s", *addr), &groupcache.HTTPPoolOptions{})
pool.Set(p...)
http.HandleFunc("/set", func(w http.ResponseWriter, r *http.Request) {
r.ParseForm()
key := r.FormValue("key")
value := r.FormValue("value")
fmt.Printf("Set: [%s]%s\n", key, value)
store[key] = value
})
http.HandleFunc("/cache", func(w http.ResponseWriter, r *http.Request) {
key := r.FormValue("key")
fmt.Printf("Fetching value for key '%s'\n", key)
ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
defer cancel()
var b []byte
err := group.Get(ctx, key, groupcache.AllocatingByteSliceSink(&b))
if err != nil {
http.Error(w, err.Error(), http.StatusNotFound)
return
}
w.Write(b)
w.Write([]byte{'\n'})
})
server := http.Server{
Addr: *addr,
Handler: pool,
}
go func() {
if err := server.ListenAndServe(); err != nil {
log.Fatalf("Failed to start HTTP server - %v", err)
}
}()
go func() {
if err := http.ListenAndServe(*addr2, nil); err != nil {
log.Fatalf("Failed to start API HTTP server - %v", err)
}
}()
fmt.Printf("Running...\n")
termChan := make(chan os.Signal, 1)
signal.Notify(termChan, syscall.SIGINT, syscall.SIGTERM)
<-termChan
}