Merge pull request #55 from tuhao1020/master

add new rotationSize option

Author: lestrrat

interface.go

@@ -45,6 +45,7 @@ type RotateLogs struct {
 	outFh         *os.File
 	pattern       *strftime.Strftime
 	rotationTime  time.Duration
+	rotationSize  int64
 	rotationCount uint
 	forceNewFile  bool
 }

options.go

@@ -12,6 +12,7 @@ const (
 	optkeyLinkName      = "link-name"
 	optkeyMaxAge        = "max-age"
 	optkeyRotationTime  = "rotation-time"
+	optkeyRotationSize  = "rotation-size"
 	optkeyRotationCount = "rotation-count"
 	optkeyForceNewFile  = "force-new-file"
 )
@@ -60,6 +61,12 @@ func WithRotationTime(d time.Duration) Option {
 	return option.New(optkeyRotationTime, d)
 }
 
+// WithRotationSize creates a new Option that sets the
+// log file size between rotation.
+func WithRotationSize(s int64) Option {
+	return option.New(optkeyRotationSize, s)
+}
+
 // WithRotationCount creates a new Option that sets the
 // number of files should be kept before it gets
 // purged from the file system.

rotatelogs.go

@@ -37,6 +37,7 @@ func New(p string, options ...Option) (*RotateLogs, error) {
 
 	var clock Clock = Local
 	rotationTime := 24 * time.Hour
+	var rotationSize int64
 	var rotationCount uint
 	var linkName string
 	var maxAge time.Duration
@@ -59,6 +60,11 @@ func New(p string, options ...Option) (*RotateLogs, error) {
 			if rotationTime < 0 {
 				rotationTime = 0
 			}
+		case optkeyRotationSize:
+			rotationSize = o.Value().(int64)
+			if rotationSize < 0 {
+				rotationSize = 0
+			}
 		case optkeyRotationCount:
 			rotationCount = o.Value().(uint)
 		case optkeyHandler:
@@ -85,6 +91,7 @@ func New(p string, options ...Option) (*RotateLogs, error) {
 		maxAge:        maxAge,
 		pattern:       pattern,
 		rotationTime:  rotationTime,
+		rotationSize: rotationSize,
 		rotationCount: rotationCount,
 		forceNewFile:  forceNewFile,
 	}, nil
@@ -140,6 +147,14 @@ func (rl *RotateLogs) getWriter_nolock(bailOnRotateFail, useGenerationalNames bo
 	baseFn := rl.genFilename()
 	filename := baseFn
 	var forceNewFile bool
+
+	fi, err := os.Stat(rl.curFn)
+	sizeRotation := false
+	if err == nil && rl.rotationSize > 0 && rl.rotationSize <= fi.Size() {
+		forceNewFile = true
+		sizeRotation = true
+	}
+
 	if baseFn != rl.curBaseFn {
 		generation = 0
 		// even though this is the first write after calling New(),
@@ -148,7 +163,7 @@ func (rl *RotateLogs) getWriter_nolock(bailOnRotateFail, useGenerationalNames bo
 			forceNewFile = true
 		}
 	} else {
-		if !useGenerationalNames {
+		if !useGenerationalNames && !sizeRotation {
 			// nothing to do
 			return rl.outFh, nil
 		}