Adding app/log/RotatingFile.go

app/log/RotatingFile.go

@@ -0,0 +1,114 @@
+package log
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"path"
+	"time"
+)
+
+type RotatingFile struct {
+	fd      *os.File
+	size    int64
+	maxSize int64
+	ts      time.Time
+	maxAge  time.Duration
+	format  string
+}
+
+func open(filename string) (*os.File, error) {
+	return os.OpenFile(filename, os.O_CREATE|os.O_RDWR|os.O_APPEND, 0o666)
+}
+
+func NewRotatingFile(filename string, maxSize int64, maxAge time.Duration) (*RotatingFile, error) {
+	if err := os.MkdirAll(path.Dir(filename), 0o766); err != nil && !os.IsExist(err) {
+		return nil, err
+	}
+
+	fd, err := open(filename)
+	if err != nil {
+		return nil, err
+	}
+
+	stat, err := fd.Stat()
+	if err != nil {
+		return nil, err
+	}
+
+	return &RotatingFile{
+		fd:      fd,
+		size:    stat.Size(),
+		maxSize: maxSize,
+		ts:      time.Now(),
+		maxAge:  maxAge,
+		format:  "2006-01-02_150405",
+	}, nil
+}
+
+func NewRotatingFileFromConfig(config Config) (*RotatingFile, error) {
+	return NewRotatingFile(config.GetFilePath(), int64(config.MaxFileSize), config.MaxTime)
+}
+
+func (w *RotatingFile) newFilename(name string) string {
+	ext := path.Ext(name)
+	if len(ext) > 0 {
+		name = name[:len(name)-len(ext)]
+	}
+	return fmt.Sprintf("%s-%s%s", name, time.Now().Format(w.format), ext)
+}
+
+// Rotate the file.
+func (w *RotatingFile) Rotate() error {
+	dst, err := os.OpenFile(w.newFilename(w.fd.Name()), os.O_CREATE|os.O_WRONLY, 0o666)
+	if err != nil {
+		return err
+	}
+	defer dst.Close()
+
+	// Seek to the beginning of file
+	if _, err = w.fd.Seek(0, io.SeekStart); err != nil {
+		return err
+	}
+
+	// And copy the contents to the new file.
+	if _, err = io.Copy(dst, w.fd); err != nil {
+		return err
+	}
+
+	// Then truncate the log.
+	if err = w.fd.Truncate(0); err != nil {
+		return err
+	}
+
+	w.size = 0
+	w.ts = time.Now()
+
+	return nil
+}
+
+// Implement io.Writer interface
+func (w *RotatingFile) Write(p []byte) (int, error) {
+	n, err := w.fd.Write(p)
+	if err != nil {
+		return n, err
+	}
+
+	w.size += int64(n)
+
+	// Check if we should rotate
+	if w.size >= w.maxSize || time.Since(w.ts) >= w.maxAge {
+		if err := w.Rotate(); err != nil {
+			return n, err
+		}
+	}
+
+	return n, nil
+}
+
+// Implement io.Closer interface
+func (w *RotatingFile) Close() error {
+	err := w.fd.Close()
+	w.fd = nil
+	return err
+}