log, errors: Introduce `rotate_compress` option (#1731)

* vendor: update Lumberjack dep

* httpserver/roller: introduce rotate_compress directive

This directive will enable gzip compression provided by [Lumberjack](https://github.com/natefinch/lumberjack/pull/43).

The directive `rotate_compress` can be `true` or `false`, being `false` by default.

* httpserver/roller: remove need to set bool with rotate_compress option

caddyhttp/errors/setup_test.go

@@ -85,13 +85,14 @@ func TestErrorsParse(t *testing.T) {
 				Roller: httpserver.DefaultLogRoller(),
 			},
 		}},
-		{`errors errors.txt { rotate_size 2 rotate_age 10 rotate_keep 3 }`, false, ErrorHandler{
+		{`errors errors.txt { rotate_size 2 rotate_age 10 rotate_keep 3 rotate_compress }`, false, ErrorHandler{
 			ErrorPages: map[int]string{},
 			Log: &httpserver.Logger{
 				Output: "errors.txt", Roller: &httpserver.LogRoller{
 					MaxSize:    2,
 					MaxAge:     10,
 					MaxBackups: 3,
+					Compress:   true,
 					LocalTime:  true,
 				},
 			},
@@ -113,6 +114,7 @@ func TestErrorsParse(t *testing.T) {
 					MaxSize:    3,
 					MaxAge:     11,
 					MaxBackups: 5,
+					Compress:   false,
 					LocalTime:  true,
 				},
 			},

caddyhttp/httpserver/roller.go

@@ -14,6 +14,7 @@ type LogRoller struct {
 	MaxSize    int
 	MaxAge     int
 	MaxBackups int
+	Compress   bool
 	LocalTime  bool
 }
 
@@ -37,6 +38,7 @@ func (l LogRoller) GetLogWriter() io.Writer {
 			MaxSize:    l.MaxSize,
 			MaxAge:     l.MaxAge,
 			MaxBackups: l.MaxBackups,
+			Compress:   l.Compress,
 			LocalTime:  l.LocalTime,
 		}
 		lumberjacks[absPath] = lj
@@ -48,7 +50,8 @@ func (l LogRoller) GetLogWriter() io.Writer {
 func IsLogRollerSubdirective(subdir string) bool {
 	return subdir == directiveRotateSize ||
 		subdir == directiveRotateAge ||
-		subdir == directiveRotateKeep
+		subdir == directiveRotateKeep ||
+		subdir == directiveRotateCompress
 }
 
 // ParseRoller parses roller contents out of c.
@@ -59,7 +62,7 @@ func ParseRoller(l *LogRoller, what string, where string) error {
 	var value int
 	var err error
 	value, err = strconv.Atoi(where)
-	if err != nil {
+	if what != directiveRotateCompress && err != nil {
 		return err
 	}
 	switch what {
@@ -69,6 +72,8 @@ func ParseRoller(l *LogRoller, what string, where string) error {
 		l.MaxAge = value
 	case directiveRotateKeep:
 		l.MaxBackups = value
+	case directiveRotateCompress:
+		l.Compress = true
 	}
 	return nil
 }
@@ -79,6 +84,7 @@ func DefaultLogRoller() *LogRoller {
 		MaxSize:    defaultRotateSize,
 		MaxAge:     defaultRotateAge,
 		MaxBackups: defaultRotateKeep,
+		Compress:   false,
 		LocalTime:  true,
 	}
 }
@@ -90,9 +96,11 @@ const (
 	defaultRotateAge = 14
 	// defaultRotateKeep is 10 files.
 	defaultRotateKeep = 10
+
 	directiveRotateSize     = "rotate_size"
 	directiveRotateAge      = "rotate_age"
 	directiveRotateKeep     = "rotate_keep"
+	directiveRotateCompress = "rotate_compress"
 )
 
 // lumberjacks maps log filenames to the logger

caddyhttp/log/setup_test.go

@@ -203,6 +203,7 @@ func TestLogParse(t *testing.T) {
 						MaxSize:    2,
 						MaxAge:     10,
 						MaxBackups: 3,
+						Compress:   false,
 						LocalTime:  true,
 					}},
 				Format: DefaultLogFormat,

vendor/gopkg.in/natefinch/lumberjack.v2/lumberjack.go

@@ -22,6 +22,8 @@
 package lumberjack
 
 import (
+	"compress/gzip"
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -35,6 +37,7 @@ import (
 
 const (
 	backupTimeFormat = "2006-01-02T15-04-05.000"
+	compressSuffix   = ".gz"
 	defaultMaxSize   = 100
 )
 
@@ -100,9 +103,16 @@ type Logger struct {
 	// time.
 	LocalTime bool `json:"localtime" yaml:"localtime"`
 
+	// Compress determines if the rotated log files should be compressed
+	// using gzip.
+	Compress bool `json:"compress" yaml:"compress"`
+
 	size int64
 	file *os.File
 	mu   sync.Mutex
+
+	millCh    chan bool
+	startMill sync.Once
 }
 
 var (
@@ -171,8 +181,8 @@ func (l *Logger) close() error {
 // Rotate causes Logger to close the existing log file and immediately create a
 // new one.  This is a helper function for applications that want to initiate
 // rotations outside of the normal rotation rules, such as in response to
-// SIGHUP.  After rotating, this initiates a cleanup of old log files according
-// to the normal rules.
+// SIGHUP.  After rotating, this initiates compression and removal of old log
+// files according to the configuration.
 func (l *Logger) Rotate() error {
 	l.mu.Lock()
 	defer l.mu.Unlock()
@@ -181,16 +191,16 @@ func (l *Logger) Rotate() error {
 
 // rotate closes the current file, moves it aside with a timestamp in the name,
 // (if it exists), opens a new file with the original filename, and then runs
-// cleanup.
+// post-rotation processing and removal.
 func (l *Logger) rotate() error {
 	if err := l.close(); err != nil {
 		return err
 	}
-
 	if err := l.openNew(); err != nil {
 		return err
 	}
-	return l.cleanup()
+	l.mill()
+	return nil
 }
 
 // openNew opens a new log file for writing, moving any old log file out of the
@@ -252,6 +262,8 @@ func backupName(name string, local bool) string {
 // would not put it over MaxSize.  If there is no such file or the write would
 // put it over the MaxSize, a new file is created.
 func (l *Logger) openExistingOrNew(writeLen int) error {
+	l.mill()
+
 	filename := l.filename()
 	info, err := os_Stat(filename)
 	if os.IsNotExist(err) {
@@ -285,10 +297,12 @@ func (l *Logger) filename() string {
 	return filepath.Join(os.TempDir(), name)
 }
 
-// cleanup deletes old log files, keeping at most l.MaxBackups files, as long as
+// millRunOnce performs compression and removal of stale log files.
+// Log files are compressed if enabled via configuration and old log
+// files are removed, keeping at most l.MaxBackups files, as long as
 // none of them are older than MaxAge.
-func (l *Logger) cleanup() error {
-	if l.MaxBackups == 0 && l.MaxAge == 0 {
+func (l *Logger) millRunOnce() error {
+	if l.MaxBackups == 0 && l.MaxAge == 0 && !l.Compress {
 		return nil
 	}
 
@@ -297,38 +311,87 @@ func (l *Logger) cleanup() error {
 		return err
 	}
 
-	var deletes []logInfo
+	var compress, remove []logInfo
 
 	if l.MaxBackups > 0 && l.MaxBackups < len(files) {
-		deletes = files[l.MaxBackups:]
-		files = files[:l.MaxBackups]
+		preserved := make(map[string]bool)
+		var remaining []logInfo
+		for _, f := range files {
+			// Only count the uncompressed log file or the
+			// compressed log file, not both.
+			fn := f.Name()
+			if strings.HasSuffix(fn, compressSuffix) {
+				fn = fn[:len(fn)-len(compressSuffix)]
+			}
+			preserved[fn] = true
+
+			if len(preserved) > l.MaxBackups {
+				remove = append(remove, f)
+			} else {
+				remaining = append(remaining, f)
+			}
+		}
+		files = remaining
 	}
 	if l.MaxAge > 0 {
 		diff := time.Duration(int64(24*time.Hour) * int64(l.MaxAge))
-
 		cutoff := currentTime().Add(-1 * diff)
 
+		var remaining []logInfo
 		for _, f := range files {
 			if f.timestamp.Before(cutoff) {
-				deletes = append(deletes, f)
+				remove = append(remove, f)
+			} else {
+				remaining = append(remaining, f)
 			}
 		}
+		files = remaining
 	}
 
-	if len(deletes) == 0 {
-		return nil
+	if l.Compress {
+		for _, f := range files {
+			if !strings.HasSuffix(f.Name(), compressSuffix) {
+				compress = append(compress, f)
+			}
+		}
 	}
 
-	go deleteAll(l.dir(), deletes)
+	for _, f := range remove {
+		errRemove := os.Remove(filepath.Join(l.dir(), f.Name()))
+		if err == nil && errRemove != nil {
+			err = errRemove
+		}
+	}
+	for _, f := range compress {
+		fn := filepath.Join(l.dir(), f.Name())
+		errCompress := compressLogFile(fn, fn+compressSuffix)
+		if err == nil && errCompress != nil {
+			err = errCompress
+		}
+	}
 
-	return nil
+	return err
 }
 
-func deleteAll(dir string, files []logInfo) {
-	// remove files on a separate goroutine
-	for _, f := range files {
+// millRun runs in a goroutine to manage post-rotation compression and removal
+// of old log files.
+func (l *Logger) millRun() {
+	for _ = range l.millCh {
 		// what am I going to do, log this?
-		_ = os.Remove(filepath.Join(dir, f.Name()))
+		_ = l.millRunOnce()
+	}
+}
+
+// mill performs post-rotation compression and removal of stale log files,
+// starting the mill goroutine if necessary.
+func (l *Logger) mill() {
+	l.startMill.Do(func() {
+		l.millCh = make(chan bool, 1)
+		go l.millRun()
+	})
+	select {
+	case l.millCh <- true:
+	default:
 	}
 }
 
@@ -347,13 +410,13 @@ func (l *Logger) oldLogFiles() ([]logInfo, error) {
 		if f.IsDir() {
 			continue
 		}
-		name := l.timeFromName(f.Name(), prefix, ext)
-		if name == "" {
+		if t, err := l.timeFromName(f.Name(), prefix, ext); err == nil {
+			logFiles = append(logFiles, logInfo{t, f})
 			continue
 		}
-		t, err := time.Parse(backupTimeFormat, name)
-		if err == nil {
+		if t, err := l.timeFromName(f.Name(), prefix, ext+compressSuffix); err == nil {
 			logFiles = append(logFiles, logInfo{t, f})
+			continue
 		}
 		// error parsing means that the suffix at the end was not generated
 		// by lumberjack, and therefore it's not a backup file.
@@ -367,17 +430,15 @@ func (l *Logger) oldLogFiles() ([]logInfo, error) {
 // timeFromName extracts the formatted time from the filename by stripping off
 // the filename's prefix and extension. This prevents someone's filename from
 // confusing time.parse.
-func (l *Logger) timeFromName(filename, prefix, ext string) string {
+func (l *Logger) timeFromName(filename, prefix, ext string) (time.Time, error) {
 	if !strings.HasPrefix(filename, prefix) {
-		return ""
+		return time.Time{}, errors.New("mismatched prefix")
 	}
-	filename = filename[len(prefix):]
-
 	if !strings.HasSuffix(filename, ext) {
-		return ""
+		return time.Time{}, errors.New("mismatched extension")
 	}
-	filename = filename[:len(filename)-len(ext)]
-	return filename
+	ts := filename[len(prefix) : len(filename)-len(ext)]
+	return time.Parse(backupTimeFormat, ts)
 }
 
 // max returns the maximum size in bytes of log files before rolling.
@@ -402,6 +463,61 @@ func (l *Logger) prefixAndExt() (prefix, ext string) {
 	return prefix, ext
 }
 
+// compressLogFile compresses the given log file, removing the
+// uncompressed log file if successful.
+func compressLogFile(src, dst string) (err error) {
+	f, err := os.Open(src)
+	if err != nil {
+		return fmt.Errorf("failed to open log file: %v", err)
+	}
+	defer f.Close()
+
+	fi, err := os_Stat(src)
+	if err != nil {
+		return fmt.Errorf("failed to stat log file: %v", err)
+	}
+
+	if err := chown(dst, fi); err != nil {
+		return fmt.Errorf("failed to chown compressed log file: %v", err)
+	}
+
+	// If this file already exists, we presume it was created by
+	// a previous attempt to compress the log file.
+	gzf, err := os.OpenFile(dst, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, fi.Mode())
+	if err != nil {
+		return fmt.Errorf("failed to open compressed log file: %v", err)
+	}
+	defer gzf.Close()
+
+	gz := gzip.NewWriter(gzf)
+
+	defer func() {
+		if err != nil {
+			os.Remove(dst)
+			err = fmt.Errorf("failed to compress log file: %v", err)
+		}
+	}()
+
+	if _, err := io.Copy(gz, f); err != nil {
+		return err
+	}
+	if err := gz.Close(); err != nil {
+		return err
+	}
+	if err := gzf.Close(); err != nil {
+		return err
+	}
+
+	if err := f.Close(); err != nil {
+		return err
+	}
+	if err := os.Remove(src); err != nil {
+		return err
+	}
+
+	return nil
+}
+
 // logInfo is a convenience struct to return the filename and its embedded
 // timestamp.
 type logInfo struct {

vendor/manifest

@@ -434,7 +434,7 @@
 			"importpath": "gopkg.in/natefinch/lumberjack.v2",
 			"repository": "https://gopkg.in/natefinch/lumberjack.v2",
 			"vcs": "git",
-			"revision": "dd45e6a67c53f673bb49ca8a001fd3a63ceb640e",
+			"revision": "df99d62fd42d8b3752c8a42c6723555372c02a03",
 			"branch": "v2.0",
 			"notests": true
 		},