network: fix server shutdown by waiting for goroutines to finish

s.Shutdown() does not wait for all goroutines of the node server to
finish normally just because the server exits without dependent
goroutines awaiting. Which causes logs to attempt to write after the
test has ended. The consequence of this bug fix is that corresponding
tests are fixed.

Close #2973
Close #2974

Signed-off-by: Ekaterina Pavlova <ekt@morphbits.io>

pkg/network/server.go

@@ -124,12 +124,14 @@ type (
 		lastRequestedBlock atomic.Uint32
 		// lastRequestedHeader contains a height of the last requested header.
 		lastRequestedHeader atomic.Uint32
-
 		register            chan Peer
 		unregister          chan peerDrop
 		handshake           chan Peer
 		quit                chan struct{}
 		relayFin            chan struct{}
+		runFin              chan struct{}
+		broadcastTxFin      chan struct{}
+		runProtoFin         chan struct{}
 
 		transactions chan *transaction.Transaction
 
@@ -141,6 +143,8 @@ type (
 
 		// started used to Start and Shutdown server only once.
 		started atomic.Bool
+
+		txHandlerLoopWG sync.WaitGroup
 	}
 
 	peerDrop struct {
@@ -183,6 +187,9 @@ func newServerFromConstructors(config ServerConfig, chain Ledger, stSync StateSy
 		config:         chain.GetConfig().ProtocolConfiguration,
 		quit:           make(chan struct{}),
 		relayFin:       make(chan struct{}),
+		runFin:         make(chan struct{}),
+		broadcastTxFin: make(chan struct{}),
+		runProtoFin:    make(chan struct{}),
 		register:       make(chan Peer),
 		unregister:     make(chan peerDrop),
 		handshake:      make(chan Peer),
@@ -279,6 +286,7 @@ func (s *Server) Start() {
 	s.initStaleMemPools()
 
 	var txThreads = optimalNumOfThreads()
+	s.txHandlerLoopWG.Add(txThreads)
 	for i := 0; i < txThreads; i++ {
 		go s.txHandlerLoop()
 	}
@@ -319,7 +327,11 @@ func (s *Server) Shutdown() {
 		s.notaryRequestPool.StopSubscriptions()
 	}
 	close(s.quit)
+	<-s.broadcastTxFin
+	<-s.runProtoFin
 	<-s.relayFin
+	<-s.runFin
+	s.txHandlerLoopWG.Wait()
 
 	_ = s.log.Sync()
 }
@@ -435,6 +447,7 @@ func (s *Server) run() {
 		addrTimer        = time.NewTimer(peerCheckTime)
 		peerTimer        = time.NewTimer(s.ProtoTickInterval)
 	)
+	defer close(s.runFin)
 	defer addrTimer.Stop()
 	defer peerTimer.Stop()
 	go s.runProto()
@@ -533,6 +546,7 @@ func (s *Server) run() {
 
 // runProto is a goroutine that manages server-wide protocol events.
 func (s *Server) runProto() {
+	defer close(s.runProtoFin)
 	pingTimer := time.NewTimer(s.PingInterval)
 	for {
 		prevHeight := s.chain.BlockHeight()
@@ -1135,6 +1149,7 @@ func (s *Server) handleTxCmd(tx *transaction.Transaction) error {
 }
 
 func (s *Server) txHandlerLoop() {
+	defer s.txHandlerLoopWG.Done()
 txloop:
 	for {
 		select {
@@ -1651,6 +1666,7 @@ func (s *Server) broadcastTxLoop() {
 		batchSize = 42
 	)
 
+	defer close(s.broadcastTxFin)
 	txs := make([]util.Uint256, 0, batchSize)
 	var timer *time.Timer