Add in process log rotation (#5778)

logger/logger.go

@@ -1,12 +1,15 @@
 package logger
 
 import (
+	"errors"
 	"io"
 	"log"
 	"os"
 	"regexp"
 	"time"
 
+	"github.com/influxdata/telegraf/internal"
+	"github.com/influxdata/telegraf/internal/rotate"
 	"github.com/influxdata/wlog"
 )
 
@@ -15,12 +18,32 @@ var prefixRegex = regexp.MustCompile("^[DIWE]!")
 // newTelegrafWriter returns a logging-wrapped writer.
 func newTelegrafWriter(w io.Writer) io.Writer {
 	return &telegrafLog{
-		writer: wlog.NewWriter(w),
+		writer:         wlog.NewWriter(w),
+		internalWriter: w,
 	}
 }
 
+// LogConfig contains the log configuration settings
+type LogConfig struct {
+	// will set the log level to DEBUG
+	Debug bool
+	//will set the log level to ERROR
+	Quiet bool
+	// will direct the logging output to a file. Empty string is
+	// interpreted as stderr. If there is an error opening the file the
+	// logger will fallback to stderr
+	Logfile string
+	// will rotate when current file at the specified time interval
+	RotationInterval internal.Duration
+	// will rotate when current file size exceeds this parameter.
+	RotationMaxSize internal.Size
+	// maximum rotated files to keep (older ones will be deleted)
+	RotationMaxArchives int
+}
+
 type telegrafLog struct {
-	writer io.Writer
+	writer         io.Writer
+	internalWriter io.Writer
 }
 
 func (t *telegrafLog) Write(b []byte) (n int, err error) {
@@ -33,31 +56,40 @@ func (t *telegrafLog) Write(b []byte) (n int, err error) {
 	return t.writer.Write(line)
 }
 
+func (t *telegrafLog) Close() error {
+	closer, isCloser := t.internalWriter.(io.Closer)
+	if !isCloser {
+		return errors.New("the underlying writer cannot be closed")
+	}
+	return closer.Close()
+}
+
 // SetupLogging configures the logging output.
-//   debug   will set the log level to DEBUG
-//   quiet   will set the log level to ERROR
-//   logfile will direct the logging output to a file. Empty string is
-//           interpreted as stderr. If there is an error opening the file the
-//           logger will fallback to stderr.
-func SetupLogging(debug, quiet bool, logfile string) {
+func SetupLogging(config LogConfig) {
+	newLogWriter(config)
+}
+
+func newLogWriter(config LogConfig) io.Writer {
 	log.SetFlags(0)
-	if debug {
+	if config.Debug {
 		wlog.SetLevel(wlog.DEBUG)
 	}
-	if quiet {
+	if config.Quiet {
 		wlog.SetLevel(wlog.ERROR)
 	}
 
-	var oFile *os.File
-	if logfile != "" {
+	var writer io.Writer
+	if config.Logfile != "" {
 		var err error
-		if oFile, err = os.OpenFile(logfile, os.O_CREATE|os.O_APPEND|os.O_WRONLY, os.ModeAppend|0644); err != nil {
-			log.Printf("E! Unable to open %s (%s), using stderr", logfile, err)
-			oFile = os.Stderr
+		if writer, err = rotate.NewFileWriter(config.Logfile, config.RotationInterval.Duration, config.RotationMaxSize.Size, config.RotationMaxArchives); err != nil {
+			log.Printf("E! Unable to open %s (%s), using stderr", config.Logfile, err)
+			writer = os.Stderr
 		}
 	} else {
-		oFile = os.Stderr
+		writer = os.Stderr
 	}
 
-	log.SetOutput(newTelegrafWriter(oFile))
+	telegrafLog := newTelegrafWriter(writer)
+	log.SetOutput(telegrafLog)
+	return telegrafLog
 }

logger/logger_test.go

@@ -2,12 +2,16 @@ package logger
 
 import (
 	"bytes"
+	"io"
 	"io/ioutil"
 	"log"
 	"os"
+	"path/filepath"
 	"testing"
 
+	"github.com/influxdata/telegraf/internal"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestWriteLogToFile(t *testing.T) {
@@ -15,7 +19,8 @@ func TestWriteLogToFile(t *testing.T) {
 	assert.NoError(t, err)
 	defer func() { os.Remove(tmpfile.Name()) }()
 
-	SetupLogging(false, false, tmpfile.Name())
+	config := createBasicLogConfig(tmpfile.Name())
+	SetupLogging(config)
 	log.Printf("I! TEST")
 	log.Printf("D! TEST") // <- should be ignored
 
@@ -28,8 +33,9 @@ func TestDebugWriteLogToFile(t *testing.T) {
 	tmpfile, err := ioutil.TempFile("", "")
 	assert.NoError(t, err)
 	defer func() { os.Remove(tmpfile.Name()) }()
-
-	SetupLogging(true, false, tmpfile.Name())
+	config := createBasicLogConfig(tmpfile.Name())
+	config.Debug = true
+	SetupLogging(config)
 	log.Printf("D! TEST")
 
 	f, err := ioutil.ReadFile(tmpfile.Name())
@@ -41,8 +47,9 @@ func TestErrorWriteLogToFile(t *testing.T) {
 	tmpfile, err := ioutil.TempFile("", "")
 	assert.NoError(t, err)
 	defer func() { os.Remove(tmpfile.Name()) }()
-
-	SetupLogging(false, true, tmpfile.Name())
+	config := createBasicLogConfig(tmpfile.Name())
+	config.Quiet = true
+	SetupLogging(config)
 	log.Printf("E! TEST")
 	log.Printf("I! TEST") // <- should be ignored
 
@@ -55,8 +62,9 @@ func TestAddDefaultLogLevel(t *testing.T) {
 	tmpfile, err := ioutil.TempFile("", "")
 	assert.NoError(t, err)
 	defer func() { os.Remove(tmpfile.Name()) }()
-
-	SetupLogging(true, false, tmpfile.Name())
+	config := createBasicLogConfig(tmpfile.Name())
+	config.Debug = true
+	SetupLogging(config)
 	log.Printf("TEST")
 
 	f, err := ioutil.ReadFile(tmpfile.Name())
@@ -68,8 +76,9 @@ func TestWriteToTruncatedFile(t *testing.T) {
 	tmpfile, err := ioutil.TempFile("", "")
 	assert.NoError(t, err)
 	defer func() { os.Remove(tmpfile.Name()) }()
-
-	SetupLogging(true, false, tmpfile.Name())
+	config := createBasicLogConfig(tmpfile.Name())
+	config.Debug = true
+	SetupLogging(config)
 	log.Printf("TEST")
 
 	f, err := ioutil.ReadFile(tmpfile.Name())
@@ -87,6 +96,23 @@ func TestWriteToTruncatedFile(t *testing.T) {
 	assert.Equal(t, f[19:], []byte("Z I! SHOULD BE FIRST\n"))
 }
 
+func TestWriteToFileInRotation(t *testing.T) {
+	tempDir, err := ioutil.TempDir("", "LogRotation")
+	require.NoError(t, err)
+	config := createBasicLogConfig(filepath.Join(tempDir, "test.log"))
+	config.RotationMaxSize = internal.Size{Size: int64(30)}
+	writer := newLogWriter(config)
+	// Close the writer here, otherwise the temp folder cannot be deleted because the current log file is in use.
+	closer, isCloser := writer.(io.Closer)
+	assert.True(t, isCloser)
+	defer func() { closer.Close(); os.RemoveAll(tempDir) }()
+
+	log.Printf("I! TEST 1") // Writes 31 bytes, will rotate
+	log.Printf("I! TEST")   // Writes 29 byes, no rotation expected
+	files, _ := ioutil.ReadDir(tempDir)
+	assert.Equal(t, 2, len(files))
+}
+
 func BenchmarkTelegrafLogWrite(b *testing.B) {
 	var msg = []byte("test")
 	var buf bytes.Buffer
@@ -96,3 +122,10 @@ func BenchmarkTelegrafLogWrite(b *testing.B) {
 		w.Write(msg)
 	}
 }
+
+func createBasicLogConfig(filename string) LogConfig {
+	return LogConfig{
+		Logfile:             filename,
+		RotationMaxArchives: -1,
+	}
+}