chore: Fix linter findings for nolintlint (part3) (#12613)

Co-authored-by: Pawel Zak <Pawel Zak>

.golangci.yml

@@ -21,6 +21,7 @@ linters:
     - makezero
     - nakedret
     - nilerr
+    - nolintlint
     - prealloc
     - predeclared
     - revive
@@ -80,6 +81,13 @@ linters-settings:
     # Tab width in spaces.
     # Default: 1
     tab-width: 4
+  nolintlint:
+    # Enable to require an explanation of nonzero length after each nolint directive.
+    # Default: false
+    require-explanation: true
+    # Enable to require nolint directives to mention the specific linter being suppressed.
+    # Default: false
+    require-specific: true
   prealloc:
     # Report pre-allocation suggestions only on simple loops that have no returns/breaks/continues/gotos in them.
     # Default: true

plugins/common/shim/goshim.go

@@ -84,7 +84,7 @@ func (s *Shim) Run(pollInterval time.Duration) error {
 		if err != nil {
 			return fmt.Errorf("RunProcessor error: %w", err)
 		}
-	} else if s.Output != nil { //nolint:revive // Not simplifying here to stay in the structure for better understanding the code
+	} else if s.Output != nil {
 		err := s.RunOutput()
 		if err != nil {
 			return fmt.Errorf("RunOutput error: %w", err)

plugins/inputs/statsd/statsd.go

@@ -876,10 +876,7 @@ func (s *Statsd) handler(conn *net.TCPConn, id string) {
 	// connection cleanup function
 	defer func() {
 		s.wg.Done()
-
+		conn.Close() //nolint:revive // Ignore the returned error as we cannot do anything about it anyway
-		// Ignore the returned error as we cannot do anything about it anyway
-		//nolint:errcheck,revive
-		conn.Close()
 
 		// Add one connection potential back to channel when this one closes
 		s.accept <- true
@@ -911,11 +908,8 @@ func (s *Statsd) handler(conn *net.TCPConn, id string) {
 
 			b := s.bufPool.Get().(*bytes.Buffer)
 			b.Reset()
-			// Writes to a bytes buffer always succeed, so do not check the errors here
+			b.Write(scanner.Bytes()) //nolint:revive // Writes to a bytes buffer always succeed, so do not check the errors here
-			//nolint:errcheck,revive
+			b.WriteByte('\n')        //nolint:revive // Writes to a bytes buffer always succeed, so do not check the errors here
-			b.Write(scanner.Bytes())
-			//nolint:errcheck,revive
-			b.WriteByte('\n')
 
 			select {
 			case s.in <- input{Buffer: b, Time: time.Now(), Addr: remoteIP}:
@@ -933,9 +927,7 @@ func (s *Statsd) handler(conn *net.TCPConn, id string) {
 
 // refuser refuses a TCP connection
 func (s *Statsd) refuser(conn *net.TCPConn) {
-	// Ignore the returned error as we cannot do anything about it anyway
+	conn.Close() //nolint:revive // Ignore the returned error as we cannot do anything about it anyway
-	//nolint:errcheck,revive
-	conn.Close()
 	s.Log.Infof("Refused TCP Connection from %s", conn.RemoteAddr())
 	s.Log.Warn("Maximum TCP Connections reached, you may want to adjust max_tcp_connections")
 }
@@ -959,13 +951,9 @@ func (s *Statsd) Stop() {
 	s.Log.Infof("Stopping the statsd service")
 	close(s.done)
 	if s.isUDP() {
-		// Ignore the returned error as we cannot do anything about it anyway
+		s.UDPlistener.Close() //nolint:revive // Ignore the returned error as we cannot do anything about it anyway
-		//nolint:errcheck,revive
-		s.UDPlistener.Close()
 	} else {
-		// Ignore the returned error as we cannot do anything about it anyway
+		s.TCPlistener.Close() //nolint:revive // Ignore the returned error as we cannot do anything about it anyway
-		//nolint:errcheck,revive
-		s.TCPlistener.Close()
 		// Close all open TCP connections
 		//  - get all conns from the s.conns map and put into slice
 		//  - this is so the forget() function doesnt conflict with looping
@@ -977,9 +965,7 @@ func (s *Statsd) Stop() {
 		}
 		s.cleanup.Unlock()
 		for _, conn := range conns {
-			// Ignore the returned error as we cannot do anything about it anyway
+			conn.Close() //nolint:revive // Ignore the returned error as we cannot do anything about it anyway
-			//nolint:errcheck,revive
-			conn.Close()
 		}
 	}
 	s.Unlock()

plugins/inputs/suricata/suricata.go

@@ -69,9 +69,7 @@ func (s *Suricata) Start(acc telegraf.Accumulator) error {
 // Stop causes the plugin to cease collecting JSON data from the socket provided
 // to Suricata.
 func (s *Suricata) Stop() {
-	// Ignore the returned error as we cannot do anything about it anyway
+	s.inputListener.Close() //nolint:revive // Ignore the returned error as we cannot do anything about it anyway
-	//nolint:errcheck,revive
-	s.inputListener.Close()
 	if s.cancel != nil {
 		s.cancel()
 	}
@@ -184,7 +182,7 @@ func (s *Suricata) parseStats(acc telegraf.Accumulator, result map[string]interf
 		return
 	}
 
-	fields := make(map[string](map[string]interface{}))
+	fields := make(map[string]map[string]interface{})
 	totalmap := make(map[string]interface{})
 	for k, v := range result["stats"].(map[string]interface{}) {
 		if k == "threads" {

plugins/inputs/synproxy/synproxy_test.go

@@ -58,9 +58,7 @@ func TestSynproxyFileInvalidHex(t *testing.T) {
 func TestNoSynproxyFile(t *testing.T) {
 	tmpfile := makeFakeSynproxyFile([]byte(synproxyFileNormal))
 	// Remove file to generate "no such file" error
-	// Ignore errors if file does not yet exist
+	os.Remove(tmpfile) //nolint:revive // Ignore errors if file does not yet exist
-	//nolint:errcheck,revive
-	os.Remove(tmpfile)
 
 	k := Synproxy{
 		statFile: tmpfile,

plugins/inputs/syslog/syslog.go

@@ -97,9 +97,7 @@ func (s *Syslog) Start(acc telegraf.Accumulator) error {
 	}
 
 	if scheme == "unix" || scheme == "unixpacket" || scheme == "unixgram" {
-		// Accept success and failure in case the file does not exist
+		os.Remove(s.Address) //nolint:revive // Accept success and failure in case the file does not exist
-		//nolint:errcheck,revive
-		os.Remove(s.Address)
 	}
 
 	if s.isStream {
@@ -141,9 +139,7 @@ func (s *Syslog) Stop() {
 	defer s.mu.Unlock()
 
 	if s.Closer != nil {
-		// Ignore the returned error as we cannot do anything about it anyway
+		s.Close() //nolint:revive // Ignore the returned error as we cannot do anything about it anyway
-		//nolint:errcheck,revive
-		s.Close()
 	}
 	s.wg.Wait()
 }
@@ -269,9 +265,7 @@ func (s *Syslog) removeConnection(c net.Conn) {
 func (s *Syslog) handle(conn net.Conn, acc telegraf.Accumulator) {
 	defer func() {
 		s.removeConnection(conn)
-		// Ignore the returned error as we cannot do anything about it anyway
+		conn.Close() //nolint:revive // Ignore the returned error as we cannot do anything about it anyway
-		//nolint:errcheck,revive
-		conn.Close()
 	}()
 
 	var p syslog.Parser
@@ -422,9 +416,7 @@ type unixCloser struct {
 
 func (uc unixCloser) Close() error {
 	err := uc.closer.Close()
-	// Accept success and failure in case the file does not exist
+	os.Remove(uc.path) //nolint:revive // Accept success and failure in case the file does not exist
-	//nolint:errcheck,revive
-	os.Remove(uc.path)
 	return err
 }
 

plugins/inputs/system/system.go

@@ -106,10 +106,7 @@ func formatUptime(uptime uint64) string {
 	minutes %= 60
 
 	fmt.Fprintf(w, "%2d:%02d", hours, minutes)
-
+	w.Flush() //nolint:revive // This will always succeed, so skip checking the error
-	// This will always succeed, so skip checking the error
-	//nolint:errcheck,revive
-	w.Flush()
 	return buf.String()
 }
 

plugins/inputs/tcp_listener/tcp_listener.go

@@ -127,9 +127,8 @@ func (t *TCPListener) Stop() {
 	t.Lock()
 	defer t.Unlock()
 	close(t.done)
-	// Ignore the returned error as we cannot do anything about it anyway
+
-	//nolint:errcheck,revive
+	t.listener.Close() //nolint:revive // Ignore the returned error as we cannot do anything about it anyway
-	t.listener.Close()
 
 	// Close all open TCP connections
 	//  - get all conns from the t.conns map and put into slice
@@ -142,9 +141,7 @@ func (t *TCPListener) Stop() {
 	}
 	t.cleanup.Unlock()
 	for _, conn := range conns {
-		// Ignore the returned error as we cannot do anything about it anyway
+		conn.Close() //nolint:revive // Ignore the returned error as we cannot do anything about it anyway
-		//nolint:errcheck,revive
-		conn.Close()
 	}
 
 	t.wg.Wait()
@@ -196,8 +193,8 @@ func (t *TCPListener) refuser(conn *net.TCPConn) {
 	fmt.Fprintf(conn, "Telegraf maximum concurrent TCP connections (%d)"+
 		" reached, closing.\nYou may want to increase max_tcp_connections in"+
 		" the Telegraf tcp listener configuration.\n", t.MaxTCPConnections)
-	//nolint:errcheck,revive
+
-	conn.Close()
+	conn.Close() //nolint:revive // Ignore the returned error as we cannot do anything about it anyway
 	t.Log.Infof("Refused TCP Connection from %s", conn.RemoteAddr())
 	t.Log.Warn("Maximum TCP Connections reached, you may want to adjust max_tcp_connections")
 }

plugins/inputs/udp_listener/udp_listener.go

@@ -120,9 +120,7 @@ func (u *UDPListener) Stop() {
 	defer u.Unlock()
 	close(u.done)
 	u.wg.Wait()
-	// Ignore the returned error as we cannot do anything about it anyway
+	u.listener.Close() //nolint:revive // Ignore the returned error as we cannot do anything about it anyway
-	//nolint:errcheck,revive
-	u.listener.Close()
 	close(u.in)
 	u.Log.Infof("Stopped service on %q", u.ServiceAddress)
 }

plugins/inputs/vsphere/finder.go

@@ -99,9 +99,7 @@ func (f *Finder) descend(ctx context.Context, root types.ManagedObjectReference,
 	if err != nil {
 		return err
 	}
-	// Ignore the returned error as we cannot do anything about it anyway
+	defer v.Destroy(ctx) //nolint:errcheck // Ignore the returned error as we cannot do anything about it anyway
-	//nolint:errcheck,revive
-	defer v.Destroy(ctx)
 	var content []types.ObjectContent
 
 	fields := []string{"name"}
@@ -119,9 +117,7 @@ func (f *Finder) descend(ctx context.Context, root types.ManagedObjectReference,
 			if err != nil {
 				return err
 			}
-			// Ignore the returned error as we cannot do anything about it anyway
+			defer v2.Destroy(ctx) //nolint:errcheck // Ignore the returned error as we cannot do anything about it anyway
-			//nolint:errcheck,revive
-			defer v2.Destroy(ctx)
 			err = v2.Retrieve(ctx, []string{resType}, fields, &content)
 			if err != nil {
 				return err

plugins/inputs/webhooks/papertrail/papertrail_webhooks.go

@@ -73,7 +73,7 @@ func (pt *PapertrailWebhook) eventHandler(w http.ResponseWriter, r *http.Request
 			}
 			pt.acc.AddFields("papertrail", fields, tags, e.ReceivedAt)
 		}
-	} else if payload.Counts != nil { //nolint:revive // Not simplifying here to stay in the structure for better understanding the code
+	} else if payload.Counts != nil {
 		// Handle count-based payload
 		for _, c := range payload.Counts {
 			for ts, count := range *c.TimeSeries {

plugins/inputs/webhooks/webhooks.go

@@ -109,8 +109,6 @@ func (wb *Webhooks) Start(acc telegraf.Accumulator) error {
 }
 
 func (wb *Webhooks) Stop() {
-	// Ignore the returned error as we cannot do anything about it anyway
+	wb.srv.Close() //nolint:revive // Ignore the returned error as we cannot do anything about it anyway
-	//nolint:errcheck,revive
-	wb.srv.Close()
 	wb.Log.Infof("Stopping the Webhooks service")
 }

plugins/inputs/zipkin/zipkin.go

@@ -120,9 +120,7 @@ func (z *Zipkin) Stop() {
 	defer z.waitGroup.Wait()
 	defer cancel()
 
-	// Ignore the returned error as we cannot do anything about it anyway
+	z.server.Shutdown(ctx) //nolint:errcheck,revive // Ignore the returned error as we cannot do anything about it anyway
-	//nolint:errcheck,revive
-	z.server.Shutdown(ctx)
 }
 
 // Listen creates an http server on the zipkin instance it is called with, and

plugins/outputs/postgresql/postgresql.go

@@ -240,7 +240,7 @@ func (p *Postgresql) writeSequential(tableSources map[string]*TableSource) error
 	if err != nil {
 		return fmt.Errorf("starting transaction: %w", err)
 	}
-	defer tx.Rollback(p.dbContext) //nolint:errcheck
+	defer tx.Rollback(p.dbContext) //nolint:errcheck // In case of failure during commit, "err" from commit will be returned
 
 	for _, tableSource := range tableSources {
 		sp := tx
@@ -317,19 +317,16 @@ func isTempError(err error) bool {
 		errClass := pgErr.Code[:2]
 		switch errClass {
 		case "23": // Integrity Constraint Violation
-			switch pgErr.Code { //nolint:revive
+			//23505 - unique_violation
-			case "23505": // unique_violation
+			if pgErr.Code == "23505" && strings.Contains(err.Error(), "pg_type_typname_nsp_index") {
-				if strings.Contains(err.Error(), "pg_type_typname_nsp_index") {
 				// Happens when you try to create 2 tables simultaneously.
 				return true
 			}
-			}
 		case "25": // Invalid Transaction State
 			// If we're here, this is a bug, but recoverable
 			return true
 		case "40": // Transaction Rollback
-			switch pgErr.Code { //nolint:revive
+			if pgErr.Code == "40P01" { // deadlock_detected
-			case "40P01": // deadlock_detected
 				return true
 			}
 		case "42": // Syntax Error or Access Rule Violation
@@ -433,7 +430,7 @@ func (p *Postgresql) writeTagTable(ctx context.Context, db dbh, tableSource *Tab
 	if err != nil {
 		return err
 	}
-	defer tx.Rollback(ctx) //nolint:errcheck
+	defer tx.Rollback(ctx) //nolint:errcheck // In case of failure during commit, "err" from commit will be returned
 
 	ident := pgx.Identifier{ttsrc.postgresql.Schema, ttsrc.Name()}
 	identTemp := pgx.Identifier{ttsrc.Name() + "_temp"}

plugins/outputs/postgresql/postgresql_test.go

@@ -354,7 +354,7 @@ func TestWriteIntegration_concurrent(t *testing.T) {
 	// Lock the table so that we ensure the writes hangs and the plugin has to open another connection.
 	tx, err := p.db.Begin(ctx)
 	require.NoError(t, err)
-	defer tx.Rollback(ctx) //nolint:errcheck
+	defer tx.Rollback(ctx) //nolint:errcheck // ignore the returned error as we cannot do anything about it anyway
 	_, err = tx.Exec(ctx, "LOCK TABLE "+utils.QuoteIdentifier(t.Name()+"_a"))
 	require.NoError(t, err)
 

plugins/outputs/postgresql/table_manager.go

@@ -148,7 +148,7 @@ func (tm *TableManager) MatchSource(ctx context.Context, db dbh, rowSource *Tabl
 // If the table cannot be modified, the returned column list is the columns which are missing from the table. This
 // includes when an error is returned.
 //
-//nolint:revive
+//nolint:revive //argument-limit conditionally more arguments allowed
 func (tm *TableManager) EnsureStructure(
 	ctx context.Context,
 	db dbh,
@@ -248,7 +248,7 @@ func (tm *TableManager) EnsureStructure(
 	if err != nil {
 		return append(addColumns, invalidColumns...), err
 	}
-	defer tx.Rollback(ctx) //nolint:errcheck
+	defer tx.Rollback(ctx) //nolint:errcheck // In case of failure during commit, "err" from commit will be returned
 	// It's possible to have multiple telegraf processes, in which we can't ensure they all lock tables in the same
 	// order. So to prevent possible deadlocks, we have to have a single lock for all schema modifications.
 	if _, err := tx.Exec(ctx, "SELECT pg_advisory_xact_lock($1)", schemaAdvisoryLockID); err != nil {
@@ -346,7 +346,7 @@ func (tm *TableManager) getColumns(ctx context.Context, db dbh, name string) (ma
 	return cols, rows.Err()
 }
 
-//nolint:revive
+//nolint:revive //argument-limit conditionally more arguments allowed
 func (tm *TableManager) update(ctx context.Context,
 	tx pgx.Tx,
 	state *tableState,

plugins/outputs/signalfx/signalfx.go

@@ -92,7 +92,7 @@ func (s *SignalFx) Connect() error {
 	if s.IngestURL != "" {
 		client.DatapointEndpoint = datapointEndpointForIngestURL(s.IngestURL)
 		client.EventEndpoint = eventEndpointForIngestURL(s.IngestURL)
-	} else if s.SignalFxRealm != "" { //nolint: revive // "Simplifying" if c {...} else {... return } would not simplify anything at all in this case
+	} else if s.SignalFxRealm != "" {
 		client.DatapointEndpoint = datapointEndpointForRealm(s.SignalFxRealm)
 		client.EventEndpoint = eventEndpointForRealm(s.SignalFxRealm)
 	} else {

plugins/outputs/stackdriver/stackdriver_test.go

@@ -69,9 +69,7 @@ func TestMain(m *testing.M) {
 		log.Fatal(err)
 	}
 
-	// Ignore the returned error as the tests will fail anyway
+	go serv.Serve(lis) //nolint:errcheck // Ignore the returned error as the tests will fail anyway
-	//nolint:errcheck,revive
-	go serv.Serve(lis)
 
 	opt := grpc.WithTransportCredentials(insecure.NewCredentials())
 	conn, err := grpc.Dial(lis.Addr().String(), opt)