Merge pull request #416 from jiyeyuran/patch-4

reuse rcache

selector/default.go

@@ -1,359 +1,25 @@
 package selector
 
 import (
-	"sync"
 	"time"
 
-	"github.com/micro/go-log"
 	"github.com/micro/go-micro/registry"
+	"github.com/micro/go-rcache"
 )
 
 type registrySelector struct {
-	so  Options
+	so Options
-	ttl time.Duration
+	rc rcache.Cache
-
-	// registry cache
-	sync.RWMutex
-	cache map[string][]*registry.Service
-	ttls  map[string]time.Time
-
-	watched map[string]bool
-
-	// used to close or reload watcher
-	reload chan bool
-	exit   chan bool
 }
 
-var (
+func (c *registrySelector) newRCache() rcache.Cache {
-	DefaultTTL = time.Minute
+	ropts := []rcache.Option{}
-)
+	if c.so.Context != nil {
-
+		if t, ok := c.so.Context.Value("selector_ttl").(time.Duration); ok {
-// isValid checks if the service is valid
+			ropts = append(ropts, rcache.WithTTL(t))
-func (c *registrySelector) isValid(services []*registry.Service, ttl time.Time) bool {
-	// no services exist
-	if len(services) == 0 {
-		return false
-	}
-
-	// ttl is invalid
-	if ttl.IsZero() {
-		return false
-	}
-
-	// time since ttl is longer than timeout
-	if time.Since(ttl) > c.ttl {
-		return false
-	}
-
-	// ok
-	return true
-}
-
-func (c *registrySelector) quit() bool {
-	select {
-	case <-c.exit:
-		return true
-	default:
-		return false
-	}
-}
-
-// cp copies a service. Because we're caching handing back pointers would
-// create a race condition, so we do this instead
-// its fast enough
-func (c *registrySelector) cp(current []*registry.Service) []*registry.Service {
-	var services []*registry.Service
-
-	for _, service := range current {
-		// copy service
-		s := new(registry.Service)
-		*s = *service
-
-		// copy nodes
-		var nodes []*registry.Node
-		for _, node := range service.Nodes {
-			n := new(registry.Node)
-			*n = *node
-			nodes = append(nodes, n)
-		}
-		s.Nodes = nodes
-
-		// copy endpoints
-		var eps []*registry.Endpoint
-		for _, ep := range service.Endpoints {
-			e := new(registry.Endpoint)
-			*e = *ep
-			eps = append(eps, e)
-		}
-		s.Endpoints = eps
-
-		// append service
-		services = append(services, s)
-	}
-
-	return services
-}
-
-func (c *registrySelector) del(service string) {
-	delete(c.cache, service)
-	delete(c.ttls, service)
-}
-
-func (c *registrySelector) get(service string) ([]*registry.Service, error) {
-	// read lock
-	c.RLock()
-
-	// check the cache first
-	services := c.cache[service]
-	// get cache ttl
-	ttl := c.ttls[service]
-
-	// got services && within ttl so return cache
-	if c.isValid(services, ttl) {
-		// make a copy
-		cp := c.cp(services)
-		// unlock the read
-		c.RUnlock()
-		// return servics
-		return cp, nil
-	}
-
-	// get does the actual request for a service and cache it
-	get := func(service string) ([]*registry.Service, error) {
-		// ask the registry
-		services, err := c.so.Registry.GetService(service)
-		if err != nil {
-			return nil, err
-		}
-
-		// cache results
-		c.Lock()
-		c.set(service, c.cp(services))
-		c.Unlock()
-
-		return services, nil
-	}
-
-	// watch service if not watched
-	if _, ok := c.watched[service]; !ok {
-		go c.run(service)
-	}
-
-	// unlock the read lock
-	c.RUnlock()
-
-	// get and return services
-	return get(service)
-}
-
-func (c *registrySelector) set(service string, services []*registry.Service) {
-	c.cache[service] = services
-	c.ttls[service] = time.Now().Add(c.ttl)
-}
-
-func (c *registrySelector) update(res *registry.Result) {
-	if res == nil || res.Service == nil {
-		return
-	}
-
-	c.Lock()
-	defer c.Unlock()
-
-	services, ok := c.cache[res.Service.Name]
-	if !ok {
-		// we're not going to cache anything
-		// unless there was already a lookup
-		return
-	}
-
-	if len(res.Service.Nodes) == 0 {
-		switch res.Action {
-		case "delete":
-			c.del(res.Service.Name)
-		}
-		return
-	}
-
-	// existing service found
-	var service *registry.Service
-	var index int
-	for i, s := range services {
-		if s.Version == res.Service.Version {
-			service = s
-			index = i
 		}
 	}
-
+	return rcache.New(c.so.Registry, ropts...)
-	switch res.Action {
-	case "create", "update":
-		if service == nil {
-			c.set(res.Service.Name, append(services, res.Service))
-			return
-		}
-
-		// append old nodes to new service
-		for _, cur := range service.Nodes {
-			var seen bool
-			for _, node := range res.Service.Nodes {
-				if cur.Id == node.Id {
-					seen = true
-					break
-				}
-			}
-			if !seen {
-				res.Service.Nodes = append(res.Service.Nodes, cur)
-			}
-		}
-
-		services[index] = res.Service
-		c.set(res.Service.Name, services)
-	case "delete":
-		if service == nil {
-			return
-		}
-
-		var nodes []*registry.Node
-
-		// filter cur nodes to remove the dead one
-		for _, cur := range service.Nodes {
-			var seen bool
-			for _, del := range res.Service.Nodes {
-				if del.Id == cur.Id {
-					seen = true
-					break
-				}
-			}
-			if !seen {
-				nodes = append(nodes, cur)
-			}
-		}
-
-		// still got nodes, save and return
-		if len(nodes) > 0 {
-			service.Nodes = nodes
-			services[index] = service
-			c.set(service.Name, services)
-			return
-		}
-
-		// zero nodes left
-
-		// only have one thing to delete
-		// nuke the thing
-		if len(services) == 1 {
-			c.del(service.Name)
-			return
-		}
-
-		// still have more than 1 service
-		// check the version and keep what we know
-		var srvs []*registry.Service
-		for _, s := range services {
-			if s.Version != service.Version {
-				srvs = append(srvs, s)
-			}
-		}
-
-		// save
-		c.set(service.Name, srvs)
-	}
-}
-
-// run starts the cache watcher loop
-// it creates a new watcher if there's a problem
-// reloads the watcher if Init is called
-// and returns when Close is called
-func (c *registrySelector) run(name string) {
-	// set watcher
-	c.Lock()
-	c.watched[name] = true
-	c.Unlock()
-
-	// delete watcher on exit
-	defer func() {
-		c.Lock()
-		delete(c.watched, name)
-		c.Unlock()
-	}()
-
-	// error counter
-	var cerr int
-
-	for {
-		// exit early if already dead
-		if c.quit() {
-			return
-		}
-
-		// create new watcher
-		w, err := c.so.Registry.Watch(
-			registry.WatchService(name),
-		)
-
-		if err != nil {
-			if c.quit() {
-				return
-			}
-			cerr++
-			if cerr > 3 {
-				log.Log(err)
-				cerr = 0
-			}
-			time.Sleep(time.Second)
-			continue
-		}
-
-		// watch for events
-		if err := c.watch(w); err != nil {
-			if c.quit() {
-				return
-			}
-			cerr++
-			if cerr > 3 {
-				cerr = 0
-				log.Log(err)
-			}
-			continue
-		}
-
-		// reset err counter
-		cerr = 0
-	}
-}
-
-// watch loops the next event and calls update
-// it returns if there's an error
-func (c *registrySelector) watch(w registry.Watcher) error {
-	defer w.Stop()
-
-	// reload chan
-	reload := make(chan bool, 1)
-
-	// manage this loop
-	go func() {
-		// wait for exit or reload signal
-		select {
-		case <-c.exit:
-		case <-c.reload:
-			reload <- true
-		}
-
-		// stop the watcher
-		w.Stop()
-	}()
-
-	for {
-		res, err := w.Next()
-		if err != nil {
-			select {
-			case <-reload:
-				return nil
-			default:
-				return err
-			}
-		}
-		c.update(res)
-	}
 }
 
 func (c *registrySelector) Init(opts ...Option) error {
@@ -361,15 +27,8 @@ func (c *registrySelector) Init(opts ...Option) error {
 		o(&c.so)
 	}
 
-	// reload the watcher
+	c.rc.Stop()
-	go func() {
+	c.rc = c.newRCache()
-		select {
-		case <-c.exit:
-			return
-		default:
-			c.reload <- true
-		}
-	}()
 
 	return nil
 }
@@ -390,7 +49,7 @@ func (c *registrySelector) Select(service string, opts ...SelectOption) (Next, e
 	// get the service
 	// try the cache first
 	// if that fails go directly to the registry
-	services, err := c.get(service)
+	services, err := c.rc.GetService(service)
 	if err != nil {
 		return nil, err
 	}
@@ -416,17 +75,8 @@ func (c *registrySelector) Reset(service string) {
 
 // Close stops the watcher and destroys the cache
 func (c *registrySelector) Close() error {
-	c.Lock()
+	c.rc.Stop()
-	c.cache = make(map[string][]*registry.Service)
-	c.watched = make(map[string]bool)
-	c.Unlock()
 
-	select {
-	case <-c.exit:
-		return nil
-	default:
-		close(c.exit)
-	}
 	return nil
 }
 
@@ -447,21 +97,10 @@ func NewSelector(opts ...Option) Selector {
 		sopts.Registry = registry.DefaultRegistry
 	}
 
-	ttl := DefaultTTL
+	s := &registrySelector{
-
+		so: sopts,
-	if sopts.Context != nil {
-		if t, ok := sopts.Context.Value("selector_ttl").(time.Duration); ok {
-			ttl = t
-		}
 	}
+	s.rc = s.newRCache()
 
-	return &registrySelector{
+	return s
-		so:      sopts,
-		ttl:     ttl,
-		watched: make(map[string]bool),
-		cache:   make(map[string][]*registry.Service),
-		ttls:    make(map[string]time.Time),
-		reload:  make(chan bool, 1),
-		exit:    make(chan bool),
-	}
 }