Golang groupcache.GetterFunc函數代碼示例

/*
Init returns an initialised Map180. d must have access to the map180 tables in the
public schema.  cacheBytes is the size of the memory cache
for land and lake layers.  region must be a valid Region.

Example:

   wm, err = map180.Init(db, map180.Region(`newzealand`), 256000000)
*/
func Init(d *sql.DB, region Region, cacheBytes int64) (*Map180, error) {
	w := &Map180{}

	var err error
	if _, ok := allZoomRegions[region]; !ok {
		err = fmt.Errorf("invalid region (allZoomRegions): %s", region)
		return w, err
	}

	if _, ok := allMapBounds[region]; !ok {
		err = fmt.Errorf("invalid region (allMapBounds): %s", region)
		return w, err
	}

	if _, ok := allNamedMapBounds[region]; !ok {
		err = fmt.Errorf("invalid region (allNamedMapBounds): %s", region)
		return w, err
	}

	zoomRegion = allZoomRegions[region]
	mapBounds = allMapBounds[region]
	namedMapBounds = allNamedMapBounds[region]

	db = d

	mapLayers = groupcache.NewGroup("mapLayers", cacheBytes, groupcache.GetterFunc(layerGetter))
	landLayers = groupcache.NewGroup("landLayers", cacheBytes, groupcache.GetterFunc(landGetter))
	lakeLayers = groupcache.NewGroup("lakeLayers", cacheBytes, groupcache.GetterFunc(lakeGetter))

	return w, nil
}

func main() {
	// STARTINIT OMIT
	me := "http://127.0.0.1:11211"
	peers := groupcache.NewHTTPPool(me)

	// Whenever peers change:
	peers.Set("http://127.0.0.1:11211")
	// ENDINIT OMIT

	// STARTGROUP OMIT
	var thumbNails = groupcache.NewGroup("thumbnail", 64<<20, groupcache.GetterFunc(
		func(ctx groupcache.Context, key string, dest groupcache.Sink) error {
			dest.SetBytes(generateThumbnail(key))
			return nil
		}))
	// ENDGROUP OMIT

	var ctx groupcache.Context

	// STARTUSE OMIT
	var data []byte
	thumbNails.Get(ctx, "big-file.jpg", groupcache.AllocatingByteSliceSink(&data))

	fmt.Println(string(data))
}

// StartCache is used to start up the groupcache mechanism
func (c *Constellation) StartCache() {
	log.Print("Starting AuthCache")
	var peers []string
	if c.PeerList == nil {
		log.Print("Initializing PeerList")
		c.PeerList = make(map[string]string)
	}

	for _, peer := range c.PeerList {
		log.Printf("Assigning peer '%s'", peer)
		if peer > "" {
			peers = append(peers, "http://"+peer+":"+GCPORT)
		}
	}
	c.Peers.Set(peers...)
	var authcache = groupcache.NewGroup(c.Groupname, 64<<20, groupcache.GetterFunc(
		func(ctx groupcache.Context, key string, dest groupcache.Sink) error {
			pod := key
			auth := c.GetAuthForPodFromConfig(pod)
			if auth > "" {
				dest.SetString(auth)
				return nil
			}
			err := fmt.Errorf("Found no value for auth on pod %s, not storing anything", pod)
			return err
		}))
	c.AuthCache = NewCache(authcache)

}

// SetCacheMaxSize enables icon caching if sizeInMB > 0.
func SetCacheMaxSize(sizeInMB int64) {
	if sizeInMB > 0 {
		iconCache = groupcache.NewGroup("icons", sizeInMB<<20, groupcache.GetterFunc(generatorFunc))
	} else {
		iconCache = nil
	}
}

func main() {
	flag.Parse()

	peers := gc.NewHTTPPool("http://localhost:" + *port)
	peers.Set("http://localhost:8001", "http://localhost:8002")

	cg = gc.NewGroup("QRCache", 1<<20, gc.GetterFunc(
		func(ctx gc.Context, key string, dest gc.Sink) error {
			fmt.Printf("asking for data of %s\n", key)
			url := fmt.Sprintf("http://chart.apis.google.com/chart?chs=300x300&cht=qr&choe=UTF-8&chl=%s", key)
			resp, err := http.Get(url)
			if err != nil {
				return nil
			}
			body, err := ioutil.ReadAll(resp.Body)
			if err != nil {
				return nil
			}
			value := base64.StdEncoding.EncodeToString(body)
			dest.SetBytes([]byte(value))
			return nil
		}))

	// run groupcache process in goroutine
	go http.ListenAndServe("localhost:"+*port, peers)

	http.Handle("/", http.HandlerFunc(QR))
	err := http.ListenAndServe(*addr, nil)
	if err != nil {
		log.Fatal("ListenAndServe:", err)
	}
}

func main() {
	/*	me := "http://127.0.0.1"
		peers := groupcache.NewHTTPPool(me)

		// Whenever peers change:
		peers.Set("http://127.0.0.1", "http://10.0.0.2", "http://10.0.0.3")*/

	getter := groupcache.GetterFunc(
		func(ctx groupcache.Context, key string, dest groupcache.Sink) error {
			//			fileName := key
			bytes := []byte{'a', 'b', 'c'}
			dest.SetBytes(bytes)
			return nil
		})

func(g *igetter) Get(ctx Content, key string, dest Sink)  {

}

	grp := groupcache.NewGroup("Grp", 64<<20, getter)
	err := grp.Get(ctx groupcache.Context, key string, dest groupcache.Sink)
	//hook
	/*	hook := groupcache.RegisterNewGroupHook(func(grp1 *groupcache.Group) {
		fmt.Println(grp1.Name())
		fmt.Println("hook")
	})*/
	
	fmt.Println(grp.Name())

	fmt.Println(grp.Stats)

}

func main() {
	flag.Parse()

	// Setup the doozer connection.
	d, err := doozer.Dial(daddr)
	if err != nil {
		log.Fatalf("connecting to doozer: %v\n", err)
	}
	defer d.Close()

	// Setup the cache.
	pool = groupcache.NewHTTPPool("http://" + addr)
	dict = groupcache.NewGroup("dict", 64<<20, groupcache.GetterFunc(
		func(ctx groupcache.Context, key string, dest groupcache.Sink) error {
			def, err := query(key)
			if err != nil {
				err = fmt.Errorf("querying remote dictionary: %v", err)
				log.Println(err)
				return err
			}

			log.Println("retrieved remote definition for", key)
			dest.SetString(def)
			return nil
		}))

	// Start watching for changes and signals.
	go watch(d)

	// Add the handler for definition requests and then start the
	// server.
	http.Handle("/define/", http.HandlerFunc(handler))
	log.Println(http.ListenAndServe(addr, nil))
}

func main() {
	// STARTINIT OMIT
	me := "http://10.0.0.1"
	peers := groupcache.NewHTTPPool(me)

	// Whenever peers change:
	peers.Set("http://10.0.0.1", "http://10.0.0.2", "http://10.0.0.3")
	// ENDINIT OMIT

	// STARTGROUP OMIT
	var thumbNails = groupcache.NewGroup("thumbnail", 64<<20, groupcache.GetterFunc(
		func(ctx groupcache.Context, key string, dest groupcache.Sink) error {
			fileName := key
			dest.SetBytes(generateThumbnail(fileName))
			return nil
		}))
	// ENDGROUP OMIT

	var ctx groupcache.Context
	var w http.ResponseWriter
	var r *http.Request

	// STARTUSE OMIT
	var data []byte
	err := thumbNails.Get(ctx, "big-file.jpg",
		groupcache.AllocatingByteSliceSink(&data))
	// ...
	_ = err               // OMIT
	var modTime time.Time // OMIT
	http.ServeContent(w, r, "big-file-thumb.jpg", modTime, bytes.NewReader(data))
	// ENDUSE OMIT
}

func main() {
	me := ":" + os.Args[1]
	peers := groupcache.NewHTTPPool("http://localhost" + me)
	peers.Set("http://localhost:8081", "http://localhost:8082",
		"http://localhost:8083")
	helloworld := groupcache.NewGroup("helloworld",
		1024*1024*10, groupcache.GetterFunc(
			func(ctx groupcache.Context,
				key string,
				dest groupcache.Sink) error {
				log.Println(me)
				dest.SetString(me + "->" + key)
				return nil
			}))
	fmt.Println("GroupName: ", helloworld.Name())
	http.HandleFunc("/xbox/", func(w http.ResponseWriter, r *http.Request) {
		parts := strings.SplitN(r.URL.Path[len("/xbox/"):], "/", 1)
		for _, x := range parts {
			fmt.Println("get: ", x)
		}
		if len(parts) != 1 {
			http.Error(w, "Bad Request", http.StatusBadRequest)
			return
		}
		var data []byte
		helloworld.Get(nil, parts[0], groupcache.AllocatingByteSliceSink(&data))
		w.Write(data)
		log.Println("Gets: ", helloworld.Stats.Gets.String())
		log.Println("Load: ", helloworld.Stats.Loads.String())
		log.Println("LocalLoad: ", helloworld.Stats.LocalLoads.String())
		log.Println("PeerError: ", helloworld.Stats.PeerErrors.String())
		log.Println("PeerLoad: ", helloworld.Stats.PeerLoads.String())
	})
	http.ListenAndServe(me, nil)
}

func InitRadosCache(name string, size int64, chunkSize int) {
	if cacheMade {
		panic("groupcache: InitRadosCache must be called only once")
	}
	cacheMade = true

	radosCache = groupcache.NewGroup(name, size, groupcache.GetterFunc(radosGetter))
	chunkPool = sync.Pool{
		New: func() interface{} { return make([]byte, chunkSize) },
	}
}

// NewGroupCache function
func NewGroupCache(cacheSize int64, redisGetFunc GetFunc) Cache {
	return &groupCacheMgr{
		group: gc.NewGroup(singleGroupName, cacheSize, gc.GetterFunc(func(ctx gc.Context, key string, dest gc.Sink) error {
			log.WithField("domain", key).Info("GroupCache:RedisRequest")

			redisRequest := api.NewValueRequest(key)
			redisGetFunc(redisRequest)
			redisResponse := <-redisRequest.Response

			log.WithField("domain", key).Info("GroupCache:RedisRequest:Done")
			return dest.SetString(redisResponse.Value)
		}))}
}

func setupGroupcache(config GroupcacheConfig) error {
	if config.GB == 0 {
		return nil
	}
	var cacheBytes int64
	cacheBytes = int64(config.GB) << 30

	pool := groupcache.NewHTTPPool(config.Host)
	if pool != nil {
		dvid.Infof("Initializing groupcache with %d GB at %s...\n", config.GB, config.Host)
		manager.gcache.cache = groupcache.NewGroup("immutable", cacheBytes, groupcache.GetterFunc(
			func(c groupcache.Context, key string, dest groupcache.Sink) error {
				// Use KeyValueDB defined as context.
				gctx, ok := c.(GroupcacheCtx)
				if !ok {
					return fmt.Errorf("bad groupcache context: expected GroupcacheCtx, got %v", c)
				}

				// First four bytes of key is instance ID to isolate groupcache collisions.
				tk := TKey(key[4:])
				data, err := gctx.KeyValueDB.Get(gctx.Context, tk)
				if err != nil {
					return err
				}
				return dest.SetBytes(data)
			}))
		manager.gcache.supported = make(map[dvid.DataSpecifier]struct{})
		for _, dataspec := range config.Instances {
			name := strings.Trim(dataspec, "\"")
			parts := strings.Split(name, ":")
			switch len(parts) {
			case 2:
				dataid := dvid.GetDataSpecifier(dvid.InstanceName(parts[0]), dvid.UUID(parts[1]))
				manager.gcache.supported[dataid] = struct{}{}
			default:
				dvid.Errorf("bad data instance specification %q given for groupcache support in config file\n", dataspec)
			}
		}

		// If we have additional peers, add them and start a listener via the HTTP port.
		if len(config.Peers) > 0 {
			peers := []string{config.Host}
			peers = append(peers, config.Peers...)
			pool.Set(peers...)
			dvid.Infof("Groupcache configuration has %d peers in addition to local host.\n", len(config.Peers))
			dvid.Infof("Starting groupcache HTTP server on %s\n", config.Host)
			http.ListenAndServe(config.Host, http.HandlerFunc(pool.ServeHTTP))
		}
	}
	return nil
}

func main() {
	var err error
	p = groupcache.NewHTTPPool("http://127.0.0.1:50000")
	// update p's list
	p.Set("http://127.0.0.1:50001", "http://127.0.0.1:50002")

	// create a new group by name and set a function for get a value by key
	// if you g.Get KEY at first time, it will store the value use sink, run the function
	// if you g.Get KEY not at first time, actually it NOT entry the function
	// does not support update a key's value
	g = groupcache.NewGroup("dns", 64<<20, groupcache.GetterFunc(
		func(ctx groupcache.Context, key string, dest groupcache.Sink) (err error) {
			if ctx == nil {
				ctx = "fuck"
			}
			log.Println(key, ctx)
			err = dest.SetString(ctx.(string))
			return
		}))

	// let it listen
	go http.ListenAndServe("127.0.0.1:50000", nil)

	// get a key's value into data

	time.Sleep(2 * time.Second)
	var data []byte
	var key = "key"
	err = g.Get("aa", key, groupcache.AllocatingByteSliceSink(&data))
	if err != nil {
		log.Println("get error:", err)
	}
	log.Println(string(data))

	time.Sleep(2 * time.Second)
	key = "key1"
	err = g.Get("bb", key, groupcache.AllocatingByteSliceSink(&data))
	if err != nil {
		log.Println("get error:", err)
	}
	log.Println(string(data))

	time.Sleep(2 * time.Second)
	key = "key"
	err = g.Get("cc", key, groupcache.AllocatingByteSliceSink(&data))
	if err != nil {
		log.Println("get error:", err)
	}
	log.Println(string(data))
}

func (g *GroupCacheProxy) MakeCache(c *Cluster, size int64) CacheGetter {
	return groupcache.NewGroup(
		"ReticulumCache", size, groupcache.GetterFunc(
			func(ctx groupcache.Context, key string, dest groupcache.Sink) error {
				// get image from disk
				ri := NewImageSpecifier(key)
				img_data, err := c.RetrieveImage(ri)
				if err != nil {
					return err
				}
				dest.SetBytes([]byte(img_data))
				return nil
			}))
}

func main() {
	runtime.GOMAXPROCS(runtime.NumCPU())

	awsAuth, err := aws.EnvAuth()
	if err != nil {
		log.Fatalf(err.Error())
	}

	s3conn := s3.New(awsAuth, getRegion())
	storage = store.NewS3Store(s3conn)

	peers = peer.DebugPool()

	peers.SetContext(func(r *http.Request) groupcache.Context {
		return fetch.RequestContext(r)
	})

	cache = groupcache.NewGroup("ImageProxyCache", 64<<20, groupcache.GetterFunc(
		func(c groupcache.Context, key string, dest groupcache.Sink) error {
			log.Printf("Cache MISS for key -> %s", key)
			// Get image data from S3
			b, err := fetch.ImageData(storage, c)
			if err != nil {
				return err
			}

			return dest.SetBytes(b)
		}))

	if !*verbose {
		logwriter, err := syslog.Dial("udp", "app_syslog:514", syslog.LOG_NOTICE, "vip")
		if err != nil {
			log.Println(err.Error())
			log.Println("using default logger")
		} else {
			log.SetOutput(logwriter)
		}
	}

	go peers.Listen()
	go listenHttp()
	go Queue.Start(4)
	log.Println("Cache listening on port :" + peers.Port())
	s := &http.Server{
		Addr:    ":" + peers.Port(),
		Handler: peers,
	}
	s.ListenAndServe()
}