disable colored log lines when output is not a terminal (#1477)

go.mod

@@ -26,6 +26,7 @@ require (
 	github.com/stretchr/testify v1.8.4
 	golang.org/x/crypto v0.11.0
 	golang.org/x/net v0.12.0
+	golang.org/x/term v0.10.0
 	gopkg.in/yaml.v2 v2.4.0
 )
 

go.sum

@@ -255,6 +255,8 @@ golang.org/x/term v0.6.0/go.mod h1:m6U89DPEgQRMq3DNkDClhWw02AUbt2daBVO4cn4Hv9U=
 golang.org/x/term v0.7.0/go.mod h1:P32HKFT3hSsZrRxla30E9HqToFYAQPCMs/zFMBUFqPY=
 golang.org/x/term v0.8.0/go.mod h1:xPskH00ivmX89bAKVGSKKtLOWNx2+17Eiy94tnKShWo=
 golang.org/x/term v0.9.0/go.mod h1:M6DEAAIenWoTxdKrOltXcmDY3rSplQUkrvaDU5FcQyo=
+golang.org/x/term v0.10.0 h1:3R7pNqamzBraeqj/Tj8qt1aQ2HpmlC+Cx/qL/7hn4/c=
+golang.org/x/term v0.10.0/go.mod h1:lpqdcUyK/oCiQxvxVrppt5ggO2KCZ5QblwqPnfZ6d5o=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=

internal/logger/destination.go

@@ -1,5 +1,9 @@
 package logger
 
+import (
+	"time"
+)
+
 // Destination is a log destination.
 type Destination int
 
@@ -15,6 +19,6 @@ const (
 )
 
 type destination interface {
-	log(Level, string, ...interface{})
+	log(time.Time, Level, string, ...interface{})
 	close()
 }

internal/logger/destination_file.go

@@ -3,6 +3,7 @@ package logger
 import (
 	"bytes"
 	"os"
+	"time"
 )
 
 type destinationFile struct {
@@ -21,9 +22,9 @@ func newDestinationFile(filePath string) (destination, error) {
 	}, nil
 }
 
-func (d *destinationFile) log(level Level, format string, args ...interface{}) {
+func (d *destinationFile) log(t time.Time, level Level, format string, args ...interface{}) {
 	d.buf.Reset()
-	writeTime(&d.buf, false)
+	writeTime(&d.buf, t, false)
 	writeLevel(&d.buf, level, false)
 	writeContent(&d.buf, format, args)
 	d.file.Write(d.buf.Bytes())

internal/logger/destination_stdout.go

@@ -3,20 +3,27 @@ package logger
 import (
 	"bytes"
 	"os"
+	"time"
+
+	"golang.org/x/term"
 )
 
 type destinationStdout struct {
+	useColor bool
+
 	buf bytes.Buffer
 }
 
 func newDestionationStdout() destination {
-	return &destinationStdout{}
+	return &destinationStdout{
+		useColor: term.IsTerminal(int(os.Stdout.Fd())),
+	}
 }
 
-func (d *destinationStdout) log(level Level, format string, args ...interface{}) {
+func (d *destinationStdout) log(t time.Time, level Level, format string, args ...interface{}) {
 	d.buf.Reset()
-	writeTime(&d.buf, true)
-	writeLevel(&d.buf, level, true)
+	writeTime(&d.buf, t, d.useColor)
+	writeLevel(&d.buf, level, d.useColor)
 	writeContent(&d.buf, format, args)
 	os.Stdout.Write(d.buf.Bytes())
 }

internal/logger/destination_syslog.go

@@ -3,6 +3,7 @@ package logger
 import (
 	"bytes"
 	"io"
+	"time"
 )
 
 type destinationSysLog struct {
@@ -21,9 +22,9 @@ func newDestinationSyslog() (destination, error) {
 	}, nil
 }
 
-func (d *destinationSysLog) log(level Level, format string, args ...interface{}) {
+func (d *destinationSysLog) log(t time.Time, level Level, format string, args ...interface{}) {
 	d.buf.Reset()
-	writeTime(&d.buf, false)
+	writeTime(&d.buf, t, false)
 	writeLevel(&d.buf, level, false)
 	writeContent(&d.buf, format, args)
 	d.syslog.Write(d.buf.Bytes())

internal/logger/logger.go

@@ -74,12 +74,11 @@ func itoa(i int, wid int) []byte {
 	return b[bp:]
 }
 
-func writeTime(buf *bytes.Buffer, doColor bool) {
+func writeTime(buf *bytes.Buffer, t time.Time, useColor bool) {
 	var intbuf bytes.Buffer
 
 	// date
-	now := time.Now()
-	year, month, day := now.Date()
+	year, month, day := t.Date()
 	intbuf.Write(itoa(year, 4))
 	intbuf.WriteByte('/')
 	intbuf.Write(itoa(int(month), 2))
@@ -88,46 +87,46 @@ func writeTime(buf *bytes.Buffer, doColor bool) {
 	intbuf.WriteByte(' ')
 
 	// time
-	hour, min, sec := now.Clock()
+	hour, min, sec := t.Clock()
 	intbuf.Write(itoa(hour, 2))
 	intbuf.WriteByte(':')
 	intbuf.Write(itoa(min, 2))
 	intbuf.WriteByte(':')
 	intbuf.Write(itoa(sec, 2))
 	intbuf.WriteByte(' ')
 
-	if doColor {
+	if useColor {
 		buf.WriteString(color.RenderString(color.Gray.Code(), intbuf.String()))
 	} else {
 		buf.WriteString(intbuf.String())
 	}
 }
 
-func writeLevel(buf *bytes.Buffer, level Level, doColor bool) {
+func writeLevel(buf *bytes.Buffer, level Level, useColor bool) {
 	switch level {
 	case Debug:
-		if doColor {
+		if useColor {
 			buf.WriteString(color.RenderString(color.Debug.Code(), "DEB"))
 		} else {
 			buf.WriteString("DEB")
 		}
 
 	case Info:
-		if doColor {
+		if useColor {
 			buf.WriteString(color.RenderString(color.Green.Code(), "INF"))
 		} else {
 			buf.WriteString("INF")
 		}
 
 	case Warn:
-		if doColor {
+		if useColor {
 			buf.WriteString(color.RenderString(color.Warn.Code(), "WAR"))
 		} else {
 			buf.WriteString("WAR")
 		}
 
 	case Error:
-		if doColor {
+		if useColor {
 			buf.WriteString(color.RenderString(color.Error.Code(), "ERR"))
 		} else {
 			buf.WriteString("ERR")
@@ -150,7 +149,9 @@ func (lh *Logger) Log(level Level, format string, args ...interface{}) {
 	lh.mutex.Lock()
 	defer lh.mutex.Unlock()
 
+	t := time.Now()
+
 	for _, dest := range lh.destinations {
-		dest.log(level, format, args...)
+		dest.log(t, level, format, args...)
 	}
 }