From 9144117c320dbad29b9fad6dbd8b9fbffb6a2c4c Mon Sep 17 00:00:00 2001
From: kiwiidb <kwinten.debacker@hotmail.com>
Date: Mon, 16 Jan 2023 17:59:41 +0100
Subject: [PATCH] add graceful shutdown context

---
 lib/service/invoicesubscription.go |  7 +------
 main.go                            | 27 ++++++++++++++++++---------
 2 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/lib/service/invoicesubscription.go b/lib/service/invoicesubscription.go
index 7440ffb..8545cc6 100644
--- a/lib/service/invoicesubscription.go
+++ b/lib/service/invoicesubscription.go
@@ -243,11 +243,6 @@ func (svc *LndhubService) InvoiceUpdateSubscription(ctx context.Context) error {
 			if err != nil {
 				svc.Logger.Errorf("Error processing invoice update subscription: %v", err)
 				sentry.CaptureException(err)
-				// TODO: close the stream somehoe before retrying?
-				// Wait 30 seconds and try to reconnect
-				// TODO: implement some backoff
-				time.Sleep(30 * time.Second)
-				invoiceSubscriptionStream, _ = svc.ConnectInvoiceSubscription(ctx)
 				continue
 			}
 
@@ -256,7 +251,7 @@ func (svc *LndhubService) InvoiceUpdateSubscription(ctx context.Context) error {
 			// Processing open invoices here could cause a race condition:
 			// We could get this notification faster than we finish the AddInvoice call
 			if rawInvoice.State == lnrpc.Invoice_OPEN {
-				svc.Logger.Infof("Invoice state is open. Ignoring update. r_hash:%v", hex.EncodeToString(rawInvoice.RHash))
+				svc.Logger.Debugf("Invoice state is open. Ignoring update. r_hash:%v", hex.EncodeToString(rawInvoice.RHash))
 				continue
 			}
 
diff --git a/main.go b/main.go
index 5bbc7f4..c96e09e 100644
--- a/main.go
+++ b/main.go
@@ -8,6 +8,7 @@ import (
 	"net/http"
 	"os"
 	"os/signal"
+	"sync"
 	"time"
 
 	cache "github.com/SporkHubr/echo-http-cache"
@@ -169,28 +170,33 @@ func main() {
 	docs.SwaggerInfo.Host = c.Host
 	e.GET("/swagger/*", echoSwagger.WrapHandler)
 
+	var backgroundWg sync.WaitGroup
+	ctx, cancelBackgroundRoutines := context.WithCancel(context.Background())
 	// Subscribe to LND invoice updates in the background
-	go svc.InvoiceUpdateSubscription(context.Background())
+	backgroundWg.Add(1)
+	go func() {
+		err = svc.InvoiceUpdateSubscription(ctx)
+		if err != nil {
+			svc.Logger.Error(err)
+		}
+		backgroundWg.Done()
+	}()
 
 	// Check the status of all pending outgoing payments
 	// A goroutine will be spawned for each one
-	err = svc.CheckAllPendingOutgoingPayments(context.Background())
+	err = svc.CheckAllPendingOutgoingPayments(ctx)
 	if err != nil {
 		svc.Logger.Error(err)
 	}
 
 	//Start webhook subscription
 	if svc.Config.WebhookUrl != "" {
-		webhookCtx, cancelWebhook := context.WithCancel(context.Background())
-		go svc.StartWebhookSubscribtion(webhookCtx, svc.Config.WebhookUrl)
-		defer cancelWebhook()
+		go svc.StartWebhookSubscribtion(ctx, svc.Config.WebhookUrl)
 	}
 
 	if svc.Config.EnableGRPC {
 		//start grpc server
-		grpcContext, grpcCancel := context.WithCancel(context.Background())
-		go svc.StartGrpcServer(grpcContext)
-		defer grpcCancel()
+		go svc.StartGrpcServer(ctx)
 	}
 
 	//Start Prometheus server if necessary
@@ -233,7 +239,10 @@ func main() {
 			e.Logger.Fatal(err)
 		}
 	}
-
+	//cancel and wait for graceful shutdown of background routines
+	cancelBackgroundRoutines()
+	backgroundWg.Wait()
+	fmt.Println("LNDhub exiting gracefully. Goodbye.")
 }
 
 func createRateLimitMiddleware(seconds int, burst int) echo.MiddlewareFunc {