xmtop/logging/logging.go
2020-02-15 14:57:18 -06:00

101 lines
2.0 KiB
Go

package logging
import (
"fmt"
"io"
"log"
"os"
"path/filepath"
"sync"
"github.com/xxxserxxx/gotop"
)
func New(c gotop.Config) (io.WriteCloser, error) {
// create the log directory
if err := os.MkdirAll(c.LogDir, 0755); err != nil {
return nil, fmt.Errorf("failed to make the log directory: %v", err)
}
w := &RotateWriter{
filename: filepath.Join(c.LogDir, c.LogFile),
maxLogSize: c.MaxLogSize,
}
err := w.rotate()
if err != nil {
return nil, err
}
// log time, filename, and line number
log.SetFlags(log.Ltime | log.Lshortfile)
// log to file
log.SetOutput(w)
stderrToLogfile(w.fp)
return w, nil
}
type RotateWriter struct {
lock sync.Mutex
filename string // should be set to the actual filename
fp *os.File
maxLogSize int64
}
func (w *RotateWriter) Close() error {
return w.fp.Close()
}
// Write satisfies the io.Writer interface.
func (w *RotateWriter) Write(output []byte) (int, error) {
w.lock.Lock()
defer w.lock.Unlock()
// Rotate if the log hits the size limit
s, err := os.Stat(w.filename)
if err == nil {
if s.Size() > w.maxLogSize {
w.rotate()
}
}
return w.fp.Write(output)
}
// Perform the actual act of rotating and reopening file.
func (w *RotateWriter) rotate() (err error) {
// Close existing file if open
if w.fp != nil {
err = w.fp.Close()
w.fp = nil
if err != nil {
return
}
}
// This will keep three logs
for i := 1; i > -1; i-- {
from := fmt.Sprintf("%s.%d", w.filename, i)
to := fmt.Sprintf("%s.%d", w.filename, i+1)
// Rename dest file if it already exists
_, err = os.Stat(from)
if err == nil {
err = os.Rename(from, to)
if err != nil {
return
}
}
}
// Rename dest file if it already exists
_, err = os.Stat(w.filename)
if err == nil {
err = os.Rename(w.filename, fmt.Sprintf("%s.%d", w.filename, 0))
if err != nil {
return
}
}
// open the log file
w.fp, err = os.OpenFile(w.filename, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0660)
if err != nil {
return fmt.Errorf("failed to open log file %s: %v", w.filename, err)
}
return nil
}