les --> lifecycle decoupled from ethbackend (#29)

eth/backend.go

@@ -54,10 +54,6 @@ import (
 )
 
 type LesServer interface {
-	Start(srvr *p2p.Server)
-	Stop()
-	APIs() []rpc.API
-	Protocols() []p2p.Protocol
 	SetBloomBitsIndexer(bbIndexer *core.ChainIndexer)
 }
 
@@ -98,7 +94,6 @@ type Ethereum struct {
 }
 
 func (s *Ethereum) AddLesServer(ls LesServer) {
-	s.lesServer = ls
 	ls.SetBloomBitsIndexer(s.bloomIndexer)
 }
 
@@ -288,19 +283,10 @@ func CreateConsensusEngine(stack *node.Node, chainConfig *params.ChainConfig, co
 // NOTE, some of these services probably need to be moved to somewhere else.
 func (s *Ethereum) APIs() []rpc.API {
 	apis := ethapi.GetAPIs(s.APIBackend)
-
-	// Append any APIs exposed explicitly by the les server
-	if s.lesServer != nil {
-		apis = append(apis, s.lesServer.APIs()...)
-	}
+
 	// Append any APIs exposed explicitly by the consensus engine
 	apis = append(apis, s.engine.APIs(s.BlockChain())...)
 
-	// Append any APIs exposed explicitly by the les server
-	if s.lesServer != nil {
-		apis = append(apis, s.lesServer.APIs()...)
-	}
-
 	// Append all the local APIs and return
 	return append(apis, []rpc.API{
 		{
@@ -525,9 +511,6 @@ func (s *Ethereum) Protocols() []p2p.Protocol {
 		protos[i].Attributes = []enr.Entry{s.currentEthEntry()}
 		protos[i].DialCandidates = s.dialCandidates
 	}
-	if s.lesServer != nil {
-		protos = append(protos, s.lesServer.Protocols()...)
-	}
 	return protos
 }
 
@@ -549,9 +532,6 @@ func (s *Ethereum) Start() error {
 	}
 	// Start the networking layer and the light server if requested
 	s.protocolManager.Start(maxPeers)
-	if s.lesServer != nil {
-		s.lesServer.Start(s.p2pServer)
-	}
 	return nil
 }
 
@@ -560,9 +540,6 @@ func (s *Ethereum) Start() error {
 func (s *Ethereum) Stop() error {
 	// Stop all the peer-related stuff first.
 	s.protocolManager.Stop()
-	if s.lesServer != nil {
-		s.lesServer.Stop()
-	}
 
 	// Then stop everything else.
 	s.bloomIndexer.Close()

les/server.go

@@ -54,6 +54,8 @@ type LesServer struct {
 	minCapacity, maxCapacity, freeCapacity uint64
 	threadsIdle                            int // Request serving threads count when system is idle.
 	threadsBusy                            int // Request serving threads count when system is busy(block insertion).
+
+	p2pSrv 		*p2p.Server
 }
 
 func NewLesServer(node *node.Node, e *eth.Ethereum, config *eth.Config) (*LesServer, error) {
@@ -87,6 +89,7 @@ func NewLesServer(node *node.Node, e *eth.Ethereum, config *eth.Config) (*LesSer
 		servingQueue: newServingQueue(int64(time.Millisecond*10), float64(config.LightServ)/100),
 		threadsBusy:  config.LightServ/100 + 1,
 		threadsIdle:  threads,
+		p2pSrv: node.Server(),
 	}
 	srv.handler = newServerHandler(srv, e.BlockChain(), e.ChainDb(), e.TxPool(), e.Synced)
 	srv.costTracker, srv.minCapacity = newCostTracker(e.ChainDb(), config)
@@ -119,6 +122,11 @@ func NewLesServer(node *node.Node, e *eth.Ethereum, config *eth.Config) (*LesSer
 			"chtroot", checkpoint.CHTRoot, "bloomroot", checkpoint.BloomRoot)
 	}
 	srv.chtIndexer.Start(e.BlockChain())
+
+	node.RegisterProtocols(srv.Protocols())
+	node.RegisterAPIs(srv.APIs())
+	node.RegisterLifecycle(srv)
+
 	return srv, nil
 }
 
@@ -160,29 +168,31 @@ func (s *LesServer) Protocols() []p2p.Protocol {
 }
 
 // Start starts the LES server
-func (s *LesServer) Start(srvr *p2p.Server) {
-	s.privateKey = srvr.PrivateKey
+func (s *LesServer) Start() error {
+	s.privateKey = s.p2pSrv.PrivateKey
 	s.handler.start()
 
 	s.wg.Add(1)
 	go s.capacityManagement()
 
-	if srvr.DiscV5 != nil {
+	if s.p2pSrv.DiscV5 != nil {
 		for _, topic := range s.lesTopics {
 			topic := topic
 			go func() {
 				logger := log.New("topic", topic)
 				logger.Info("Starting topic registration")
 				defer logger.Info("Terminated topic registration")
 
-				srvr.DiscV5.RegisterTopic(topic, s.closeCh)
+				s.p2pSrv.DiscV5.RegisterTopic(topic, s.closeCh)
 			}()
 		}
 	}
+
+	return nil
 }
 
 // Stop stops the LES service
-func (s *LesServer) Stop() {
+func (s *LesServer) Stop() error {
 	close(s.closeCh)
 
 	// Disconnect existing sessions.
@@ -201,6 +211,8 @@ func (s *LesServer) Stop() {
 	s.chtIndexer.Close()
 	s.wg.Wait()
 	log.Info("Les server stopped")
+
+	return nil
 }
 
 func (s *LesServer) SetBloomBitsIndexer(bloomIndexer *core.ChainIndexer) {