From 2ec2ef9ad6bb1d8ca877b19d0ba9b51efac1e93f Mon Sep 17 00:00:00 2001
From: Jesse Lee <gatsby1118@gmail.com>
Date: Fri, 3 Nov 2023 05:05:26 -0400
Subject: [PATCH] fix: go routine error handling

---
 cmd/monitor/monitor.go | 29 +++++++++++++++++------------
 go.mod                 |  2 +-
 go.sum                 |  2 --
 3 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/cmd/monitor/monitor.go b/cmd/monitor/monitor.go
index 621ca437..755b900a 100644
--- a/cmd/monitor/monitor.go
+++ b/cmd/monitor/monitor.go
@@ -102,20 +102,25 @@ func monitor(ctx context.Context) error {
 	isUiRendered := false
 	errChan := make(chan error)
 	go func() {
-		for {
-			err = fetchBlocks(ctx, ec, ms, rpc, isUiRendered)
-			if err != nil {
-				continue
-			}
+		select {
+		case <-ctx.Done(): // listens for a cancellation signal
+			return // exit the goroutine when the context is done
+		default:
+			for {
+				err = fetchBlocks(ctx, ec, ms, rpc, isUiRendered)
+				if err != nil {
+					continue
+				}
 
-			if !isUiRendered {
-				go func() {
-					errChan <- renderMonitorUI(ctx, ec, ms, rpc)
-				}()
-				isUiRendered = true
-			}
+				if !isUiRendered {
+					go func() {
+						errChan <- renderMonitorUI(ctx, ec, ms, rpc)
+					}()
+					isUiRendered = true
+				}
 
-			time.Sleep(interval)
+				time.Sleep(interval)
+			}
 		}
 	}()
 
diff --git a/go.mod b/go.mod
index 4e4445b4..50995f16 100644
--- a/go.mod
+++ b/go.mod
@@ -5,6 +5,7 @@ go 1.21
 require (
 	cloud.google.com/go/datastore v1.14.0
 	github.com/btcsuite/btcutil v1.0.2
+	github.com/cenkalti/backoff/v4 v4.2.1
 	github.com/ethereum/go-ethereum v1.13.2
 	github.com/gizak/termui/v3 v3.1.0
 	github.com/google/gofuzz v1.2.0
@@ -45,7 +46,6 @@ require (
 	github.com/bits-and-blooms/bitset v1.7.0 // indirect
 	github.com/btcsuite/btcd/btcec/v2 v2.3.2 // indirect
 	github.com/btcsuite/btcd/chaincfg/chainhash v1.0.2 // indirect
-	github.com/cenkalti/backoff/v4 v4.2.1 // indirect
 	github.com/cespare/xxhash/v2 v2.2.0 // indirect
 	github.com/cockroachdb/errors v1.8.1 // indirect
 	github.com/cockroachdb/logtags v0.0.0-20190617123548-eb05cc24525f // indirect
diff --git a/go.sum b/go.sum
index fdc21927..29ce29d0 100644
--- a/go.sum
+++ b/go.sum
@@ -88,8 +88,6 @@ github.com/btcsuite/goleveldb v0.0.0-20160330041536-7834afc9e8cd/go.mod h1:F+uVa
 github.com/btcsuite/snappy-go v0.0.0-20151229074030-0bdef8d06723/go.mod h1:8woku9dyThutzjeg+3xrA5iCpBRH8XEEg3lh6TiUghc=
 github.com/btcsuite/websocket v0.0.0-20150119174127-31079b680792/go.mod h1:ghJtEyQwv5/p4Mg4C0fgbePVuGr935/5ddU9Z3TmDRY=
 github.com/btcsuite/winsvc v1.0.0/go.mod h1:jsenWakMcC0zFBFurPLEAyrnc/teJEM1O46fmI40EZs=
-github.com/cenkalti/backoff v2.2.1+incompatible h1:tNowT99t7UNflLxfYYSlKYsBpXdEet03Pg2g16Swow4=
-github.com/cenkalti/backoff v2.2.1+incompatible/go.mod h1:90ReRw6GdpyfrHakVjL/QHaoyV4aDUVVkXQJJJ3NXXM=
 github.com/cenkalti/backoff/v4 v4.2.1 h1:y4OZtCnogmCPw98Zjyt5a6+QwPLGkiQsYW5oUqylYbM=
 github.com/cenkalti/backoff/v4 v4.2.1/go.mod h1:Y3VNntkOUPxTVeUxJ/G5vcM//AlwfmyYozVcomhLiZE=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=