chore(linters): Enable `preferDecodeRune` and `preferFprint` checkers for gocritic (#14453)

.golangci.yml

@@ -118,6 +118,8 @@ linters-settings:
       - weakCond
       # performance
       - equalFold
+      - preferDecodeRune
+      - preferFprint      
       - preferStringWriter
       - stringXbytes
   gosec:

cmd/telegraf/main.go

@@ -178,7 +178,7 @@ func runApp(args []string, outputBuffer io.Writer, pprof Server, c TelegrafConfi
 			}
 			sort.Strings(names)
 			for _, k := range names {
-				outputBuffer.Write([]byte(fmt.Sprintf("  %s\n", k)))
+				fmt.Fprintf(outputBuffer, "  %s\n", k)
 			}
 			return nil
 		// print available input plugins
@@ -191,7 +191,7 @@ func runApp(args []string, outputBuffer io.Writer, pprof Server, c TelegrafConfi
 			}
 			sort.Strings(names)
 			for _, k := range names {
-				outputBuffer.Write([]byte(fmt.Sprintf("  %s\n", k)))
+				fmt.Fprintf(outputBuffer, "  %s\n", k)
 			}
 			return nil
 		// print usage for a plugin, ie, 'telegraf --usage mysql'
@@ -204,7 +204,7 @@ func runApp(args []string, outputBuffer io.Writer, pprof Server, c TelegrafConfi
 			return nil
 		// DEPRECATED
 		case cCtx.Bool("version"):
-			outputBuffer.Write([]byte(fmt.Sprintf("%s\n", internal.FormatFullVersion())))
+			fmt.Fprintf(outputBuffer, "%s\n", internal.FormatFullVersion())
 			return nil
 		// DEPRECATED
 		case cCtx.Bool("sample-config"):
@@ -363,7 +363,7 @@ func runApp(args []string, outputBuffer io.Writer, pprof Server, c TelegrafConfi
 				Name:  "version",
 				Usage: "print current version to stdout",
 				Action: func(cCtx *cli.Context) error {
-					outputBuffer.Write([]byte(fmt.Sprintf("%s\n", internal.FormatFullVersion())))
+					fmt.Fprintf(outputBuffer, "%s\n", internal.FormatFullVersion())
 					return nil
 				},
 			},

cmd/telegraf/main_test.go

@@ -133,7 +133,7 @@ func (m *MockConfig) CollectDeprecationInfos(_, _, _, _ []string) map[string][]c
 
 func (m *MockConfig) PrintDeprecationList(plugins []config.PluginDeprecationInfo) {
 	for _, p := range plugins {
-		_, _ = m.Buffer.Write([]byte(fmt.Sprintf("plugin name: %s\n", p.Name)))
+		fmt.Fprintf(m.Buffer, "plugin name: %s\n", p.Name)
 	}
 }
 

cmd/telegraf/printer.go

@@ -364,14 +364,14 @@ func printConfig(name string, p telegraf.PluginDescriber, op string, commented b
 		if di.RemovalIn != "" {
 			removalNote = " and will be removed in " + di.RemovalIn
 		}
-		outputBuffer.Write([]byte(fmt.Sprintf("\n%s ## DEPRECATED: The %q plugin is deprecated in version %s%s, %s.",
-			comment, name, di.Since, removalNote, di.Notice)))
+		fmt.Fprintf(outputBuffer, "\n%s ## DEPRECATED: The %q plugin is deprecated in version %s%s, %s.",
+			comment, name, di.Since, removalNote, di.Notice)
 	}
 
 	sample := p.SampleConfig()
 	if sample == "" {
-		outputBuffer.Write([]byte(fmt.Sprintf("\n#[[%s.%s]]", op, name)))
-		outputBuffer.Write([]byte(fmt.Sprintf("\n%s  # no configuration\n\n", comment)))
+		fmt.Fprintf(outputBuffer, "\n#[[%s.%s]]", op, name)
+		fmt.Fprintf(outputBuffer, "\n%s  # no configuration\n\n", comment)
 	} else {
 		lines := strings.Split(sample, "\n")
 		outputBuffer.Write([]byte("\n"))

plugins/inputs/disque/disque.go

@@ -106,7 +106,7 @@ func (d *Disque) gatherServer(addr *url.URL, acc telegraf.Accumulator) error {
 		if addr.User != nil {
 			pwd, set := addr.User.Password()
 			if set && pwd != "" {
-				if _, err := c.Write([]byte(fmt.Sprintf("AUTH %s\r\n", pwd))); err != nil {
+				if _, err := fmt.Fprintf(c, "AUTH %s\r\n", pwd); err != nil {
 					return err
 				}
 

plugins/inputs/influxdb_listener/influxdb_listener.go

@@ -490,7 +490,7 @@ func badRequest(res http.ResponseWriter, errString string) error {
 	}
 	res.Header().Set("X-Influxdb-Error", errString)
 	res.WriteHeader(http.StatusBadRequest)
-	_, err := res.Write([]byte(fmt.Sprintf(`{"error":%q}`, errString)))
+	_, err := fmt.Fprintf(res, `{"error":%q}`, errString)
 	return err
 }
 
@@ -499,7 +499,7 @@ func partialWrite(res http.ResponseWriter, errString string) error {
 	res.Header().Set("X-Influxdb-Version", "1.0")
 	res.Header().Set("X-Influxdb-Error", errString)
 	res.WriteHeader(http.StatusBadRequest)
-	_, err := res.Write([]byte(fmt.Sprintf(`{"error":%q}`, errString)))
+	_, err := fmt.Fprintf(res, `{"error":%q}`, errString)
 	return err
 }
 

plugins/inputs/intel_dlb/intel_dlb_test.go

@@ -950,7 +950,7 @@ func simulateSocketResponseForGather(socket net.Listener, t *testing.T) {
 
 	require.NoError(t, err)
 	eventdevListWithSecondIndex := []string{"/eventdev/port_list", "/eventdev/queue_list"}
-	_, err = conn.Write([]byte(fmt.Sprintf(`{%q: [0, 1]}`, eventdevListWithSecondIndex[0])))
+	_, err = fmt.Fprintf(conn, `{%q: [0, 1]}`, eventdevListWithSecondIndex[0])
 	require.NoError(t, err)
 }
 

plugins/inputs/varnish/varnish_test.go

@@ -92,7 +92,7 @@ func flatten(metrics []*testutil.Metric) map[string]interface{} {
 	for _, m := range metrics {
 		buf := &bytes.Buffer{}
 		for k, v := range m.Tags {
-			buf.WriteString(fmt.Sprintf("%s=%s", k, v))
+			fmt.Fprintf(buf, "%s=%s", k, v)
 		}
 		for k, v := range m.Fields {
 			flat[fmt.Sprintf("%s %s", buf.String(), k)] = v

plugins/parsers/csv/parser.go

@@ -199,16 +199,17 @@ func (p *Parser) compile(r io.Reader) *csv.Reader {
 	// ensures that the reader reads records of different lengths without an error
 	csvReader.FieldsPerRecord = -1
 	if !p.invalidDelimiter && p.Delimiter != "" {
-		csvReader.Comma = []rune(p.Delimiter)[0]
+		csvReader.Comma, _ = utf8.DecodeRuneInString(p.Delimiter)
 	}
 	// Check if delimiter is invalid
 	if p.invalidDelimiter && p.Delimiter != "" {
-		csvReader.Comma = []rune(commaByte)[0]
+		csvReader.Comma, _ = utf8.DecodeRuneInString(commaByte)
 	}
 	if p.Comment != "" {
-		csvReader.Comment = []rune(p.Comment)[0]
+		csvReader.Comment, _ = utf8.DecodeRuneInString(p.Comment)
 	}
 	csvReader.TrimLeadingSpace = p.TrimSpace
+
 	return csvReader
 }
 

plugins/serializers/csv/csv.go

@@ -8,6 +8,7 @@ import (
 	"sort"
 	"strconv"
 	"time"
+	"unicode/utf8"
 
 	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/internal"
@@ -46,7 +47,7 @@ func (s *Serializer) Init() error {
 
 	// Initialize the writer
 	s.writer = csv.NewWriter(&s.buffer)
-	s.writer.Comma = []rune(s.Separator)[0]
+	s.writer.Comma, _ = utf8.DecodeRuneInString(s.Separator)
 	s.writer.UseCRLF = runtime.GOOS == "windows"
 
 	return nil