services: update logs flush after services shutdown

Added sync logs for every service separately to provide the ability to
have a custom logger for each service. This commit makes the code follow
the zap usages rules: `Sync calls the underlying Core's Sync method,
flushing any buffered log entries. Applications should take care to
call Sync before exiting.`

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

pkg/consensus/consensus.go

@@ -296,6 +296,7 @@ func (s *service) Shutdown() {
 			s.wallet.Close()
 		}
 	}
+	_ = s.log.Sync()
 }
 
 func (s *service) eventLoop() {

pkg/core/blockchain.go

@@ -1447,6 +1447,7 @@ func (bc *Blockchain) Close() {
 	close(bc.stopCh)
 	<-bc.runToExitCh
 	bc.addLock.Unlock()
+	_ = bc.log.Sync()
 }
 
 // AddBlock accepts successive block for the Blockchain, verifies it and

pkg/network/server.go

@@ -326,6 +326,8 @@ func (s *Server) Shutdown() {
 	}
 	close(s.quit)
 	<-s.relayFin
+
+	_ = s.log.Sync()
 }
 
 // AddService allows to add a service to be started/stopped by Server.

pkg/services/metrics/metrics.go

@@ -75,4 +75,5 @@ func (ms *Service) ShutDown() {
 			ms.log.Error("can't shut service down", zap.String("endpoint", srv.Addr), zap.Error(err))
 		}
 	}
+	_ = ms.log.Sync()
 }

pkg/services/notary/notary.go

@@ -228,6 +228,7 @@ func (n *Notary) Shutdown() {
 	close(n.stopCh)
 	<-n.done
 	n.wallet.Close()
+	_ = n.Config.Log.Sync()
 }
 
 // IsAuthorized returns whether Notary service currently is authorized to collect

pkg/services/oracle/oracle.go

@@ -192,6 +192,7 @@ func (o *Oracle) Shutdown() {
 	o.ResponseHandler.Shutdown()
 	<-o.done
 	o.wallet.Close()
+	_ = o.Log.Sync()
 }
 
 // Start runs the oracle service in a separate goroutine.

pkg/services/rpcsrv/server.go

@@ -482,6 +482,7 @@ func (s *Server) Shutdown() {
 
 	// Wait for handleSubEvents to finish.
 	<-s.subEventsToExitCh
+	_ = s.log.Sync()
 }
 
 // SetOracleHandler allows to update oracle handler used by the Server.

pkg/services/stateroot/validators.go

@@ -77,6 +77,7 @@ func (s *service) Shutdown() {
 	if s.wallet != nil {
 		s.wallet.Close()
 	}
+	_ = s.log.Sync()
 }
 
 func (s *service) signAndSend(r *state.MPTRoot) error {