From ce01a67b5ada69e7fc658ac8a7cc66fa305e435e Mon Sep 17 00:00:00 2001
From: Simon Pasquier <spasquie@redhat.com>
Date: Fri, 21 Jan 2022 17:16:04 +0100
Subject: [PATCH] notify/sns: detect FIFO topic based on the rendered value

Since the TopicARN field is a template string, it's safer to check for
the ".fifo" suffix in the rendered string.

Signed-off-by: Simon Pasquier <spasquie@redhat.com>
---
 notify/sns/sns.go | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/notify/sns/sns.go b/notify/sns/sns.go
index 281e46a8..104c4a45 100644
--- a/notify/sns/sns.go
+++ b/notify/sns/sns.go
@@ -43,7 +43,6 @@ type Notifier struct {
 	logger  log.Logger
 	client  *http.Client
 	retrier *notify.Retrier
-	isFifo  *bool
 }
 
 // New returns a new SNS notification handler.
@@ -68,7 +67,7 @@ func (n *Notifier) Notify(ctx context.Context, alert ...*types.Alert) (bool, err
 		tmpl = notify.TmplText(n.tmpl, data, &err)
 	)
 
-	client, err := createSNSClient(n.client, n, tmpl)
+	client, err := n.createSNSClient(tmpl)
 	if err != nil {
 		if e, ok := err.(awserr.RequestFailure); ok {
 			return n.retrier.Check(e.StatusCode(), strings.NewReader(e.Message()))
@@ -77,7 +76,7 @@ func (n *Notifier) Notify(ctx context.Context, alert ...*types.Alert) (bool, err
 		}
 	}
 
-	publishInput, err := createPublishInput(ctx, n, tmpl)
+	publishInput, err := n.createPublishInput(ctx, tmpl)
 	if err != nil {
 		return true, err
 	}
@@ -96,7 +95,7 @@ func (n *Notifier) Notify(ctx context.Context, alert ...*types.Alert) (bool, err
 	return false, nil
 }
 
-func createSNSClient(httpClient *http.Client, n *Notifier, tmpl func(string) string) (*sns.SNS, error) {
+func (n *Notifier) createSNSClient(tmpl func(string) string) (*sns.SNS, error) {
 	var creds *credentials.Credentials = nil
 	// If there are provided sigV4 credentials we want to use those to create a session.
 	if n.conf.Sigv4.AccessKey != "" && n.conf.Sigv4.SecretKey != "" {
@@ -133,7 +132,7 @@ func createSNSClient(httpClient *http.Client, n *Notifier, tmpl func(string) str
 		creds = stscreds.NewCredentials(stsSess, n.conf.Sigv4.RoleARN)
 	}
 	// Use our generated session with credentials to create the SNS Client.
-	client := sns.New(sess, &aws.Config{Credentials: creds, HTTPClient: httpClient})
+	client := sns.New(sess, &aws.Config{Credentials: creds, HTTPClient: n.client})
 	// We will always need a region to be set by either the local config or the environment.
 	if aws.StringValue(sess.Config.Region) == "" {
 		return nil, fmt.Errorf("region not configured in sns.sigv4.region or in default credentials chain")
@@ -141,19 +140,16 @@ func createSNSClient(httpClient *http.Client, n *Notifier, tmpl func(string) str
 	return client, nil
 }
 
-func createPublishInput(ctx context.Context, n *Notifier, tmpl func(string) string) (*sns.PublishInput, error) {
+func (n *Notifier) createPublishInput(ctx context.Context, tmpl func(string) string) (*sns.PublishInput, error) {
 	publishInput := &sns.PublishInput{}
-	messageAttributes := createMessageAttributes(n, tmpl)
+	messageAttributes := n.createMessageAttributes(tmpl)
 	// Max message size for a message in a SNS publish request is 256KB, except for SMS messages where the limit is 1600 characters/runes.
 	messageSizeLimit := 256 * 1024
 	if n.conf.TopicARN != "" {
-		topicTmpl := tmpl(n.conf.TopicARN)
-		publishInput.SetTopicArn(topicTmpl)
-		if n.isFifo == nil {
-			// If we are using a topic ARN it could be a FIFO topic specified by the topic postfix .fifo.
-			n.isFifo = aws.Bool(n.conf.TopicARN[len(n.conf.TopicARN)-5:] == ".fifo")
-		}
-		if *n.isFifo {
+		topicARN := tmpl(n.conf.TopicARN)
+		publishInput.SetTopicArn(topicARN)
+		// If we are using a topic ARN, it could be a FIFO topic specified by the topic's suffix ".fifo".
+		if strings.HasSuffix(topicARN, ".fifo") {
 			// Deduplication key and Message Group ID are only added if it's a FIFO SNS Topic.
 			key, err := notify.ExtractGroupKey(ctx)
 			if err != nil {
@@ -204,7 +200,7 @@ func validateAndTruncateMessage(message string, maxMessageSizeInBytes int) (stri
 	return string(truncated), true, nil
 }
 
-func createMessageAttributes(n *Notifier, tmpl func(string) string) map[string]*sns.MessageAttributeValue {
+func (n *Notifier) createMessageAttributes(tmpl func(string) string) map[string]*sns.MessageAttributeValue {
 	// Convert the given attributes map into the AWS Message Attributes Format.
 	attributes := make(map[string]*sns.MessageAttributeValue, len(n.conf.Attributes))
 	for k, v := range n.conf.Attributes {