fix(outputs.syslog): Trim field-names belonging to explicit SDIDs correctly (#16014)

plugins/outputs/syslog/syslog.go

@@ -121,13 +121,14 @@ func (s *Syslog) Write(metrics []telegraf.Metric) (err error) {
 		}
 	}
 	for _, metric := range metrics {
-		var msg *rfc5424.SyslogMessage
-		if msg, err = s.mapper.MapMetricToSyslogMessage(metric); err != nil {
+		msg, err := s.mapper.MapMetricToSyslogMessage(metric)
+		if err != nil {
 			s.Log.Errorf("Failed to create syslog message: %v", err)
 			continue
 		}
-		var msgBytesWithFraming []byte
-		if msgBytesWithFraming, err = s.getSyslogMessageBytesWithFraming(msg); err != nil {
+
+		msgBytesWithFraming, err := s.getSyslogMessageBytesWithFraming(msg)
+		if err != nil {
 			s.Log.Errorf("Failed to convert syslog message with framing: %v", err)
 			continue
 		}

plugins/outputs/syslog/syslog_mapper.go

@@ -53,23 +53,26 @@ func (sm *SyslogMapper) mapStructuredData(metric telegraf.Metric, msg *rfc5424.S
 }
 
 func (sm *SyslogMapper) mapStructuredDataItem(key, value string, msg *rfc5424.SyslogMessage) {
+	// Do not add already reserved keys
 	if sm.reservedKeys[key] {
 		return
 	}
-	isExplicitSdid := false
+
+	// Add keys matching one of the sd-IDs
 	for _, sdid := range sm.Sdids {
-		k := strings.TrimLeft(key, sdid+sm.Separator)
-		if len(key) > len(k) {
-			isExplicitSdid = true
+		if k := strings.TrimPrefix(key, sdid+sm.Separator); key != k {
 			msg.SetParameter(sdid, k, value)
-			break
+			return
 		}
 	}
-	if !isExplicitSdid && len(sm.DefaultSdid) > 0 {
+
+	// Add remaining keys with the default sd-ID if configured
+	if sm.DefaultSdid == "" {
+		return
+	}
 	k := strings.TrimPrefix(key, sm.DefaultSdid+sm.Separator)
 	msg.SetParameter(sm.DefaultSdid, k, value)
 }
-}
 
 func (sm *SyslogMapper) mapAppname(metric telegraf.Metric, msg *rfc5424.SyslogMessage) {
 	if value, ok := metric.GetTag("appname"); ok {

plugins/outputs/syslog/syslog_test.go

@@ -1,7 +1,10 @@
 package syslog
 
 import (
+	"bytes"
 	"net"
+	"os"
+	"path/filepath"
 	"sync"
 	"testing"
 	"time"
@@ -9,9 +12,12 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/config"
 	"github.com/influxdata/telegraf/internal"
 	"github.com/influxdata/telegraf/metric"
 	"github.com/influxdata/telegraf/models"
+	"github.com/influxdata/telegraf/plugins/outputs"
+	"github.com/influxdata/telegraf/plugins/parsers/influx"
 	"github.com/influxdata/telegraf/testutil"
 	"github.com/leodido/go-syslog/v4/nontransparent"
 )
@@ -428,3 +434,153 @@ func TestStartupErrorBehaviorRetry(t *testing.T) {
 	wg.Wait()
 	require.NotEmpty(t, string(buf))
 }
+
+func TestCases(t *testing.T) {
+	// Get all testcase directories
+	folders, err := os.ReadDir("testcases")
+	require.NoError(t, err)
+
+	// Register the plugin
+	outputs.Add("syslog", func() telegraf.Output { return newSyslog() })
+
+	for _, f := range folders {
+		// Only handle folders
+		if !f.IsDir() {
+			continue
+		}
+
+		t.Run(f.Name(), func(t *testing.T) {
+			testcasePath := filepath.Join("testcases", f.Name())
+			configFilename := filepath.Join(testcasePath, "telegraf.conf")
+			inputFilename := filepath.Join(testcasePath, "input.influx")
+			expectedFilename := filepath.Join(testcasePath, "expected.out")
+			expectedErrorFilename := filepath.Join(testcasePath, "expected.err")
+
+			// Get parser to parse input and expected output
+			parser := &influx.Parser{}
+			require.NoError(t, parser.Init())
+
+			// Load the input data
+			input, err := testutil.ParseMetricsFromFile(inputFilename, parser)
+			require.NoError(t, err)
+
+			// Read the expected output if any
+			var expected []byte
+			if _, err := os.Stat(expectedFilename); err == nil {
+				expected, err = os.ReadFile(expectedFilename)
+				require.NoError(t, err)
+			}
+
+			// Read the expected output if any
+			var expectedError string
+			if _, err := os.Stat(expectedErrorFilename); err == nil {
+				expectedErrors, err := testutil.ParseLinesFromFile(expectedErrorFilename)
+				require.NoError(t, err)
+				require.Len(t, expectedErrors, 1)
+				expectedError = expectedErrors[0]
+			}
+
+			// Configure the plugin
+			cfg := config.NewConfig()
+			require.NoError(t, cfg.LoadConfig(configFilename))
+			require.Len(t, cfg.Outputs, 1)
+
+			// Create a mock-server to receive the data
+			server, err := newMockServer()
+			require.NoError(t, err)
+
+			var wg sync.WaitGroup
+			wg.Add(1)
+			go func() {
+				defer wg.Done()
+				server.listen()
+			}()
+			defer server.close()
+
+			// Setup the plugin
+			plugin := cfg.Outputs[0].Output.(*Syslog)
+			plugin.Address = "udp://" + server.address()
+			plugin.Log = testutil.Logger{}
+			require.NoError(t, plugin.Init())
+			require.NoError(t, plugin.Connect())
+			defer plugin.Close()
+
+			// Write the data and wait for it to arrive
+			err = plugin.Write(input)
+			if expectedError != "" {
+				require.ErrorContains(t, err, expectedError)
+				return
+			}
+			require.NoError(t, err)
+			require.NoError(t, plugin.Close())
+
+			require.Eventuallyf(t, func() bool {
+				return server.len() >= len(expected)
+			}, 3*time.Second, 100*time.Millisecond, "received %q", server.message())
+
+			// Check the received data
+			require.Equal(t, string(expected), server.message())
+		})
+	}
+}
+
+type mockServer struct {
+	conn *net.UDPConn
+
+	data bytes.Buffer
+	err  error
+
+	sync.Mutex
+}
+
+func newMockServer() (*mockServer, error) {
+	addr, err := net.ResolveUDPAddr("udp", "127.0.0.1:0")
+	if err != nil {
+		return nil, err
+	}
+
+	conn, err := net.ListenUDP("udp", addr)
+	if err != nil {
+		return nil, err
+	}
+
+	return &mockServer{conn: conn}, nil
+}
+
+func (s *mockServer) address() string {
+	return s.conn.LocalAddr().String()
+}
+
+func (s *mockServer) listen() {
+	buf := make([]byte, 2048)
+	for {
+		n, err := s.conn.Read(buf)
+		if err != nil {
+			s.err = err
+			return
+		}
+		s.Lock()
+		_, _ = s.data.Write(buf[:n])
+		s.Unlock()
+	}
+}
+
+func (s *mockServer) close() error {
+	if s.conn == nil {
+		return nil
+	}
+
+	return s.conn.Close()
+}
+
+func (s *mockServer) message() string {
+	s.Lock()
+	defer s.Unlock()
+	return s.data.String()
+}
+
+func (s *mockServer) len() int {
+	s.Lock()
+	defer s.Unlock()
+	return s.data.Len()
+}

plugins/outputs/syslog/testcases/issue_16012/expected.out

@@ -0,0 +1 @@
+342 <13>1 2024-10-11T21:30:04Z draco Telegraf - scc-change-logs [additional entityUid="6b580296-7199-47b5-9736-9b91329c284e" lastEventDate="2024-10-09T19:26:13Z" status="COMPLETED" uid="544ee602-1f4c-4f5f-bbd2-365d865d78b3"][events action="UPDATE" date="2024-10-09T19:26:08Z" description="Changed ASA Config" diff="" username="user@mydomain.com"]

plugins/outputs/syslog/testcases/issue_16012/input.influx

@@ -0,0 +1 @@
+scc-change-logs,host=draco events_description="Changed ASA Config",events_diff="@@ -5,1 +5,1 @@\\n-: Written by lockhart at 18:53:02.210 UTC Tue Oct 8 2024\\n+: Written by lockhart at 19:24:54.048 UTC Wed Oct 9 2024\\n@@ -135,2 +135,0 @@\\n-object network 1.1.1.1\\n-host 1.1.1.1\\n@@ -239,0 +237,2 @@\\n+object network 1.1.1.1\\n+host 1.1.1.1\\n@@ -1108,1 +1108,1 @@\\n-Cryptochecksum:b06f479add1a10f8388a2958d0ee0018\\n+Cryptochecksum:b858dfb10323f3dbc9694a49b8c94168",events_username="user@mydomain.com",events_date="2024-10-09T19:26:08Z",events_action="UPDATE",uid="544ee602-1f4c-4f5f-bbd2-365d865d78b3",status="COMPLETED",lastEventDate="2024-10-09T19:26:13Z",entityUid="6b580296-7199-47b5-9736-9b91329c284e" 1728682204000000000

plugins/outputs/syslog/testcases/issue_16012/telegraf.conf

@@ -0,0 +1,4 @@
+[[outputs.syslog]]
+  address = "udp://127.0.0.1:0"
+  default_sdid = "additional"
+  sdids = ["events"]