From 454a429e10d30cd3658b8ea103845b98e2e9983d Mon Sep 17 00:00:00 2001
From: siddontang <siddontang@gmail.com>
Date: Tue, 29 Apr 2014 08:43:39 +0800
Subject: [PATCH] add nullhandler and rotatingfilehandler

---
 log/handler.go  | 80 +++++++++++++++++++++++++++++++++++++++++++++++++
 log/log_test.go | 36 ++++++++++++++++++++++
 2 files changed, 116 insertions(+)

diff --git a/log/handler.go b/log/handler.go
index 87b835a..af4acb4 100644
--- a/log/handler.go
+++ b/log/handler.go
@@ -32,6 +32,21 @@ func (h *StreamHandler) Close() error {
 	return nil
 }
 
+type NullHandler struct {
+}
+
+func NewNullHandler() (*NullHandler, error) {
+	return new(NullHandler), nil
+}
+
+func (h *NullHandler) Write(b []byte) (n int, err error) {
+	return len(b), nil
+}
+
+func (h *NullHandler) Close() {
+
+}
+
 type FileHandler struct {
 	fd *os.File
 }
@@ -57,6 +72,71 @@ func (h *FileHandler) Close() error {
 	return h.fd.Close()
 }
 
+type RotatingFileHandler struct {
+	fd *os.File
+
+	fileName    string
+	maxBytes    int
+	backupCount int
+}
+
+func NewRotatingFileHandler(fileName string, maxBytes int, backupCount int) (*RotatingFileHandler, error) {
+	h := new(RotatingFileHandler)
+
+	h.fileName = fileName
+	h.maxBytes = maxBytes
+	h.backupCount = backupCount
+
+	var err error
+	h.fd, err = os.OpenFile(fileName, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
+	if err != nil {
+		return nil, err
+	}
+
+	return h, nil
+}
+
+func (h *RotatingFileHandler) Write(p []byte) (n int, err error) {
+	h.doRollover()
+	return h.fd.Write(p)
+}
+
+func (h *RotatingFileHandler) Close() error {
+	if h.fd != nil {
+		return h.fd.Close()
+	}
+	return nil
+}
+
+func (h *RotatingFileHandler) doRollover() {
+	f, err := h.fd.Stat()
+	if err != nil {
+		return
+	}
+
+	if h.maxBytes <= 0 {
+		return
+	} else if f.Size() < int64(h.maxBytes) {
+		return
+	}
+
+	if h.backupCount > 0 {
+		h.fd.Close()
+
+		for i := h.backupCount - 1; i > 0; i-- {
+			sfn := fmt.Sprintf("%s.%d", h.fileName, i)
+			dfn := fmt.Sprintf("%s.%d", h.fileName, i+1)
+
+			os.Rename(sfn, dfn)
+		}
+
+		dfn := fmt.Sprintf("%s.1", h.fileName)
+		os.Rename(h.fileName, dfn)
+
+		h.fd, _ = os.OpenFile(h.fileName, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
+	}
+}
+
 //refer: http://docs.python.org/2/library/logging.handlers.html
 //same like python TimedRotatingFileHandler
 
diff --git a/log/log_test.go b/log/log_test.go
index e5e022b..67d3b0b 100644
--- a/log/log_test.go
+++ b/log/log_test.go
@@ -14,3 +14,39 @@ func TestStdStreamLog(t *testing.T) {
 
 	Info("hello world")
 }
+
+func TestRotatingFileLog(t *testing.T) {
+	path := "./test_log"
+	os.RemoveAll(path)
+
+	os.Mkdir(path, 0777)
+	fileName := path + "/test"
+
+	h, err := NewRotatingFileHandler(fileName, 10, 2)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	buf := make([]byte, 10)
+
+	h.Write(buf)
+
+	h.Write(buf)
+
+	if _, err := os.Stat(fileName + ".1"); err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err := os.Stat(fileName + ".2"); err == nil {
+		t.Fatal(err)
+	}
+
+	h.Write(buf)
+	if _, err := os.Stat(fileName + ".2"); err != nil {
+		t.Fatal(err)
+	}
+
+	h.Close()
+
+	os.RemoveAll(path)
+}