Merge pull request #129 from libp2p/feat/cache-interface-addrs

feat: cache interface addresses for 1 minute

swarm.go

@@ -20,6 +20,7 @@ import (
 	goprocessctx "github.com/jbenet/goprocess/context"
 
 	filter "github.com/libp2p/go-maddr-filter"
+	ma "github.com/multiformats/go-multiaddr"
 	mafilter "github.com/whyrusleeping/multiaddr-filter"
 )
 
@@ -58,6 +59,10 @@ type Swarm struct {
 
 	listeners struct {
 		sync.RWMutex
+
+		ifaceListenAddres []ma.Multiaddr
+		cacheEOL          time.Time
+
 		m map[transport.Listener]struct{}
 	}
 

swarm_addr.go

 package swarm
 
 import (
+	"time"
+
 	addrutil "github.com/libp2p/go-addr-util"
 	ma "github.com/multiformats/go-multiaddr"
 )
@@ -9,6 +11,10 @@ import (
 func (s *Swarm) ListenAddresses() []ma.Multiaddr {
 	s.listeners.RLock()
 	defer s.listeners.RUnlock()
+	return s.listenAddressesNoLock()
+}
+
+func (s *Swarm) listenAddressesNoLock() []ma.Multiaddr {
 	addrs := make([]ma.Multiaddr, 0, len(s.listeners.m))
 	for l := range s.listeners.m {
 		addrs = append(addrs, l.Multiaddr())
@@ -16,9 +22,47 @@ func (s *Swarm) ListenAddresses() []ma.Multiaddr {
 	return addrs
 }
 
+const ifaceAddrsCacheDuration = 1 * time.Minute
+
 // InterfaceListenAddresses returns a list of addresses at which this swarm
 // listens. It expands "any interface" addresses (/ip4/0.0.0.0, /ip6/::) to
 // use the known local interfaces.
 func (s *Swarm) InterfaceListenAddresses() ([]ma.Multiaddr, error) {
-	return addrutil.ResolveUnspecifiedAddresses(s.ListenAddresses(), nil)
+	s.listeners.RLock() // RLock start
+
+	ifaceListenAddres := s.listeners.ifaceListenAddres
+	isEOL := time.Now().After(s.listeners.cacheEOL)
+	s.listeners.RUnlock() // RLock end
+
+	if ifaceListenAddres != nil && !isEOL {
+		// Cache is valid
+		return ifaceListenAddres, nil
+	}
+
+	// Cache is not valid
+	// Perfrom double checked locking
+
+	s.listeners.Lock() // Lock start
+
+	ifaceListenAddres = s.listeners.ifaceListenAddres
+	isEOL = time.Now().After(s.listeners.cacheEOL)
+	if ifaceListenAddres == nil || isEOL {
+		// Cache is still invalid
+
+		var err error
+		ifaceListenAddres, err = addrutil.ResolveUnspecifiedAddresses(
+			s.listenAddressesNoLock(), nil)
+
+		if err != nil {
+			s.listeners.Unlock() // Lock early exit
+			return nil, err
+		}
+
+		s.listeners.ifaceListenAddres = ifaceListenAddres
+		s.listeners.cacheEOL = time.Now().Add(ifaceAddrsCacheDuration)
+	}
+
+	s.listeners.Unlock() // Lock end
+
+	return ifaceListenAddres, nil
 }

swarm_listen.go

@@ -2,6 +2,7 @@ package swarm
 
 import (
 	"fmt"
+	"time"
 
 	"github.com/libp2p/go-libp2p-core/network"
 
@@ -55,6 +56,7 @@ func (s *Swarm) AddListenAddr(a ma.Multiaddr) error {
 	}
 	s.refs.Add(1)
 	s.listeners.m[list] = struct{}{}
+	s.listeners.cacheEOL = time.Time{}
 	s.listeners.Unlock()
 
 	maddr := list.Multiaddr()
@@ -69,6 +71,7 @@ func (s *Swarm) AddListenAddr(a ma.Multiaddr) error {
 			list.Close()
 			s.listeners.Lock()
 			delete(s.listeners.m, list)
+			s.listeners.cacheEOL = time.Time{}
 			s.listeners.Unlock()
 			s.refs.Done()
 		}()