Gracefully shutdown watched address fill service on interrupt

cmd/serve.go

@@ -101,9 +101,11 @@ func serve() {
 		logWithCommand.Info("state validator disabled")
 	}
 
+	var watchedAddressFillService *fill.Service
 	if serverConfig.WatchedAddressGapFillerEnabled {
-		service := fill.New(serverConfig)
-		go service.Start()
+		watchedAddressFillService = fill.New(serverConfig)
+		wg.Add(1)
+		go watchedAddressFillService.Start(wg)
 		logWithCommand.Info("watched address gap filler enabled")
 	} else {
 		logWithCommand.Info("watched address gap filler disabled")
@@ -115,6 +117,9 @@ func serve() {
 	if graphQL != nil {
 		graphQL.Stop()
 	}
+	if watchedAddressFillService != nil {
+		watchedAddressFillService.Stop()
+	}
 	server.Stop()
 	wg.Wait()
 }

pkg/fill/service.go

@@ -19,6 +19,7 @@ package fill
 import (
 	"math"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -46,6 +47,7 @@ type Service struct {
 	db       *sqlx.DB
 	client   *rpc.Client
 	interval int
+	quitChan chan bool
 }
 
 // NewServer creates a new Service
@@ -54,12 +56,32 @@ func New(config *serve.Config) *Service {
 		db:       config.DB,
 		client:   config.Client,
 		interval: config.WatchedAddressGapFillInterval,
+		quitChan: make(chan bool),
 	}
 }
 
 // Start is used to begin the service
-func (s *Service) Start() {
+func (s *Service) Start(wg *sync.WaitGroup) {
+	defer wg.Done()
 	for {
+		select {
+		case <-s.quitChan:
+			log.Info("quiting eth ipld server process")
+			return
+		default:
+			s.fill()
+		}
+	}
+}
+
+// Stop is used to gracefully stop the service
+func (s *Service) Stop() {
+	log.Info("stopping watched address gap filler")
+	close(s.quitChan)
+}
+
+// fill performs the filling of indexing gap for watched addresses
+func (s *Service) fill() {
 	// Wait for specified interval duration
 	time.Sleep(time.Duration(s.interval) * time.Second)
 
@@ -98,7 +120,6 @@ func (s *Service) Start() {
 			s.UpdateLastFilledAt(blockNumber, fillAddresses)
 		}
 	}
-	}
 }
 
 // GetFillAddresses finds the encompassing range to perform fill for the given watched addresses