Try to fix heartbeat renew issue more fully

This approach first sets the remaining visibility timeout to zero.
This should ensure that the message is available to re-find as soon
as the process looks for it.

Correspondingly the delay between checks is much shorter, as there
shouldn't be a reason for much delay.

1 files changed, 13 insertions, 4 deletions

diff --git a/aws.go b/aws.go
index 5d66178..e3381ef 100644
--- a/aws.go
+++ b/aws.go
@@ -17,7 +17,7 @@ import (
 )
 
 const PreprocPattern = `_bin[0-9].[0-9].png`
-const heartbeatRetry = 20
+const heartbeatRetry = 100
 
 type Qmsg struct {
 	Id, Handle, Body string
@@ -155,8 +155,17 @@ func (a *AwsConn) QueueHeartbeat(msg Qmsg, qurl string, duration int64) (Qmsg, e
 		// Check if the visibility timeout has exceeded the maximum allowed,
 		// and if so try to find the message again to get a new handle.
 		if ok && aerr.Code() == "InvalidParameterValue" {
+			// First try to set the visibilitytimeout to zero to immediately
+			// make the message available to receive
+			z := int64(0)
+			_, _ = a.sqssvc.ChangeMessageVisibility(&sqs.ChangeMessageVisibilityInput{
+				ReceiptHandle:     &msg.Handle,
+				QueueUrl:          &qurl,
+				VisibilityTimeout: &z,
+			})
+
 			// Try heartbeatRetry times to find the message
-			for range [heartbeatRetry]bool{} {
+			for i := 0; i < heartbeatRetry; i++ {
 				msgResult, err := a.sqssvc.ReceiveMessage(&sqs.ReceiveMessageInput{
 					MaxNumberOfMessages: aws.Int64(10),
 					VisibilityTimeout:   &duration,
@@ -175,8 +184,8 @@ func (a *AwsConn) QueueHeartbeat(msg Qmsg, qurl string, duration int64) (Qmsg, e
 						}, nil
 					}
 				}
-				// Wait a little in case existing visibilitytimeout needs to expire
-				time.Sleep((2 * time.Duration(duration) / heartbeatRetry) * time.Second)
+				// Wait a second before trying again
+				time.Sleep(time.Second)
 			}
 			return Qmsg{}, errors.New("Heartbeat error failed to find message to update heartbeat")
 		} else {