From dd48666357a94979ff50a0570b02ca8b1f3c2566 Mon Sep 17 00:00:00 2001
From: Alex Vanin <alexey@nspcc.ru>
Date: Tue, 13 Oct 2020 18:40:35 +0300
Subject: [PATCH] [#72] Shutdown inner ring app if RPC node has been terminated

Adopt error channel from Listener interface.

Signed-off-by: Alex Vanin <alexey@nspcc.ru>
---
 cmd/neofs-ir/main.go       | 12 +++++++++---
 pkg/innerring/innerring.go | 21 ++++++++++++++++++---
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/cmd/neofs-ir/main.go b/cmd/neofs-ir/main.go
index 2f634f5b..32c1d52b 100644
--- a/cmd/neofs-ir/main.go
+++ b/cmd/neofs-ir/main.go
@@ -10,6 +10,7 @@ import (
 	"github.com/nspcc-dev/neofs-node/pkg/util/grace"
 	"github.com/nspcc-dev/neofs-node/pkg/util/logger"
 	"github.com/nspcc-dev/neofs-node/pkg/util/profiler"
+	"go.uber.org/zap"
 )
 
 const (
@@ -44,6 +45,7 @@ func main() {
 	exitErr(err)
 
 	ctx := grace.NewGracefulContext(log)
+	intErr := make(chan error) // internal inner ring errors
 
 	pprof := profiler.NewProfiler(log, cfg)
 	prometheus := profiler.NewMetrics(log, cfg)
@@ -66,15 +68,19 @@ func main() {
 	}
 
 	// start inner ring
-	err = innerRing.Start(ctx)
+	err = innerRing.Start(ctx, intErr)
 	if err != nil {
 		exitErr(err)
 	}
 
 	log.Info("application started")
 
-	// todo: select ctx.Done or exported error channel
-	<-ctx.Done()
+	select {
+	case <-ctx.Done():
+	case err := <-intErr:
+		// todo: restart application instead of shutdown
+		log.Info("internal error", zap.String("msg", err.Error()))
+	}
 
 	innerRing.Stop()
 
diff --git a/pkg/innerring/innerring.go b/pkg/innerring/innerring.go
index c9558a58..8f725f21 100644
--- a/pkg/innerring/innerring.go
+++ b/pkg/innerring/innerring.go
@@ -75,7 +75,7 @@ const (
 )
 
 // Start runs all event providers.
-func (s *Server) Start(ctx context.Context) error {
+func (s *Server) Start(ctx context.Context, intError chan<- error) error {
 	err := s.initConfigFromBlockchain()
 	if err != nil {
 		return err
@@ -83,8 +83,23 @@ func (s *Server) Start(ctx context.Context) error {
 
 	s.localTimers.Start(ctx) // local timers start ticking
 
-	go s.morphListener.Listen(ctx)   // listen for neo:morph events
-	go s.mainnetListener.Listen(ctx) // listen for neo:mainnet events
+	morphErr := make(chan error)
+	mainnnetErr := make(chan error)
+
+	// anonymous function to multiplex error channels
+	go func() {
+		select {
+		case <-ctx.Done():
+			return
+		case err := <-morphErr:
+			intError <- errors.Wrap(err, "sidechain")
+		case err := <-mainnnetErr:
+			intError <- errors.Wrap(err, "mainnet")
+		}
+	}()
+
+	go s.morphListener.ListenWithError(ctx, morphErr)      // listen for neo:morph events
+	go s.mainnetListener.ListenWithError(ctx, mainnnetErr) // listen for neo:mainnet events
 
 	return nil
 }