From bccecef13bc574ca9386cd55d4ce247cf2248ab5 Mon Sep 17 00:00:00 2001
From: Joshua Powers <powersj@influxdata.com>
Date: Tue, 11 Jan 2022 15:15:13 -0700
Subject: [PATCH] fix: correctly set ASCII trailer for syslog output (#10393)

---
 plugins/outputs/syslog/syslog.go      |  6 +++++-
 plugins/outputs/syslog/syslog_test.go | 26 ++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/plugins/outputs/syslog/syslog.go b/plugins/outputs/syslog/syslog.go
index d5925d4df..78308b6b0 100644
--- a/plugins/outputs/syslog/syslog.go
+++ b/plugins/outputs/syslog/syslog.go
@@ -219,7 +219,11 @@ func (s *Syslog) getSyslogMessageBytesWithFraming(msg *rfc5424.SyslogMessage) ([
 		return append([]byte(strconv.Itoa(len(msgBytes))+" "), msgBytes...), nil
 	}
 	// Non-transparent framing
-	return append(msgBytes, byte(s.Trailer)), nil
+	trailer, err := s.Trailer.Value()
+	if err != nil {
+		return nil, err
+	}
+	return append(msgBytes, byte(trailer)), nil
 }
 
 func (s *Syslog) initializeSyslogMapper() {
diff --git a/plugins/outputs/syslog/syslog_test.go b/plugins/outputs/syslog/syslog_test.go
index f245bcc84..f4948b421 100644
--- a/plugins/outputs/syslog/syslog_test.go
+++ b/plugins/outputs/syslog/syslog_test.go
@@ -8,6 +8,7 @@ import (
 
 	"github.com/stretchr/testify/require"
 
+	"github.com/influxdata/go-syslog/v3/nontransparent"
 	"github.com/influxdata/telegraf"
 	framing "github.com/influxdata/telegraf/internal/syslog"
 	"github.com/influxdata/telegraf/metric"
@@ -58,6 +59,31 @@ func TestGetSyslogMessageWithFramingNonTransparent(t *testing.T) {
 	messageBytesWithFraming, err := s.getSyslogMessageBytesWithFraming(syslogMessage)
 	require.NoError(t, err)
 
+	require.Equal(t, "<13>1 2010-11-10T23:00:00Z testhost Telegraf - testmetric -\n", string(messageBytesWithFraming), "Incorrect Octect counting framing")
+}
+
+func TestGetSyslogMessageWithFramingNonTransparentNul(t *testing.T) {
+	// Init plugin
+	s := newSyslog()
+	s.initializeSyslogMapper()
+	s.Framing = framing.NonTransparent
+	s.Trailer = nontransparent.NUL
+
+	// Init metrics
+	m1 := metric.New(
+		"testmetric",
+		map[string]string{
+			"hostname": "testhost",
+		},
+		map[string]interface{}{},
+		time.Date(2010, time.November, 10, 23, 0, 0, 0, time.UTC),
+	)
+
+	syslogMessage, err := s.mapper.MapMetricToSyslogMessage(m1)
+	require.NoError(t, err)
+	messageBytesWithFraming, err := s.getSyslogMessageBytesWithFraming(syslogMessage)
+	require.NoError(t, err)
+
 	require.Equal(t, "<13>1 2010-11-10T23:00:00Z testhost Telegraf - testmetric -\x00", string(messageBytesWithFraming), "Incorrect Octect counting framing")
 }