fix readme.md

README.md

@@ -111,3 +111,73 @@ func main() {
 
 ---
 ## 2. 同时写日志到文件
+
+### 2.1 使用 `logx`的 `FileWriter`
+
+```go
+package main
+
+import (
+	"io"
+	"os"
+	"time"
+
+	"github.com/zituocn/logx"
+)
+
+func init() {
+	logx.SetWriter(io.MultiWriter(
+		os.Stdout,
+		logx.NewFileWriter(logx.FileOptions{
+			StorageType: logx.StorageTypeDay,
+			MaxDay:      7,
+			Dir:         "./logs",
+			Prefix:      "web",
+		}))).SetColor(false)
+}
+
+func main() {
+	logx.Infof("这是一个字串: %s", time.Now())
+	logx.Debugf("这是一个对象: %#v", time.Now())
+}
+```
+**代码说明**：
+
+1. `logx.SetWriter` 时，使用了` io.MultiWriter`
+2. 把日志输出到了`os.Stdout` 和`logx.FileWriter`
+3. 设置不显示颜色 `SetColor(false)`
+
+
+### 2.2 自己设计一个io.Writer
+
+
+可以自己设计一个实现了 `io.Writer` ，由 `logx.SetWriter` 传入，可以是文件或网络。
+
+
+```go
+package main
+
+import (
+	"github.com/zituocn/logx"
+	"io"
+	"os"
+	"time"
+)
+
+func init() {
+	myWriter, err := os.OpenFile("./my_log_file.log", os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0664)
+	if err != nil {
+		panic(err)
+	}
+	logx.SetWriter(io.MultiWriter(
+		os.Stdout,
+		myWriter,
+	)).SetColor(false)
+}
+
+func main() {
+	logx.Infof("这是一个字串: %s", time.Now())
+	logx.Debugf("这是一个对象: %#v", time.Now())
+}
+
+```

file.go

@@ -2,12 +2,17 @@ package logx
 
 import (
 	"fmt"
+	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sync"
 	"time"
 )
 
+const (
+	nextSecond = 3600
+)
+
 type StorageType int
 
 const (
@@ -58,7 +63,7 @@ type FileOptions struct {
 	Prefix string
 
 	// date 日期
-	data string
+	date string
 }
 
 // FileWriter 文件存储实现
@@ -75,20 +80,22 @@ func NewFileWriter(opts ...FileOptions) *FileWriter {
 		FileOptions: opt,
 		mu:          &sync.Mutex{},
 	}
+	w.initFile()
+	go w.clearLogFile()
+	go w.startTimer()
 	return w
 }
 
 func (w *FileWriter) Write(p []byte) (n int, err error) {
 	w.mu.Lock()
 	defer w.mu.Unlock()
-	w.initFile()
 	return w.file.Write(p)
 }
 
 func (w *FileWriter) initFile() {
 	now := time.Now()
 	date := now.Format(w.StorageType.getFileFormat())
-	if w.data != date && w.file != nil {
+	if w.date != date && w.file != nil {
 		_ = w.file.Close()
 		w.file = nil
 	}
@@ -104,8 +111,73 @@ func (w *FileWriter) initFile() {
 			panic(errO)
 		}
 		w.file = file
-		w.data = date
+		w.date = date
+	}
+}
+
+func (w *FileWriter) startTimer() {
+	now := time.Now()
+	nextTime := now.Add(nextSecond * time.Second)
+	second := time.Duration(nextTime.Sub(now).Seconds())
+	w.timer(second)
+}
+
+func (w *FileWriter) timer(second time.Duration) {
+	timer := time.NewTicker(second * time.Second)
+	for {
+		select {
+		case <-timer.C:
+			{
+				w.clearLogFile()
+				nextTimer := time.NewTicker(nextSecond * time.Second)
+				for {
+					select {
+					case <-nextTimer.C:
+						w.startTimer()
+						return
+					}
+				}
+			}
+		}
+	}
+}
+
+func (w *FileWriter) clearLogFile() {
+	now := time.Now()
+	files := getDirFiles(w.Dir)
+	for _, item := range files {
+		modTime := item.ModTime
+		flag := modTime.Add(time.Hour * 24 * time.Duration(w.MaxDay-1)).Before(now)
+		if flag {
+			_ = os.Remove(w.Dir + item.Name)
+		}
+	}
+}
+
+// FileInfo file info
+type FileInfo struct {
+	Name    string
+	ModTime time.Time
+	Size    int64
+}
+
+// getDirFiles return log files
+func getDirFiles(path string) (files []*FileInfo) {
+	dir, err := ioutil.ReadDir(path)
+	if err != nil {
+		return
+	}
+	files = make([]*FileInfo, 0)
+	for _, fi := range dir {
+		if !fi.IsDir() {
+			files = append(files, &FileInfo{
+				Name:    fi.Name(),
+				ModTime: fi.ModTime(),
+				Size:    fi.Size(),
+			})
+		}
 	}
+	return
 }
 
 func prepareFileWriterOption(opts []FileOptions) FileOptions {