/
logger.go
85 lines (74 loc) · 1.88 KB
/
logger.go
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package util
import (
"errors"
"fmt"
"io"
"log"
"os"
"path/filepath"
"sync"
"time"
)
type LoggerOptions struct {
UseStdout bool
FilePath string
AdditionalWriters []io.Writer
}
func NewPrefixLogger(prefix string) (*log.Logger, error) {
name := fmt.Sprintf("%v_log_%v.txt", prefix, time.Now().Unix())
return NewLogger(LoggerOptions{true, name, []io.Writer{}})
}
func NewDefaultLogger() (*log.Logger, error) {
return NewPrefixLogger("default")
}
// Logger can be used concurrently.
func NewLogger(loggerOptions LoggerOptions) (*log.Logger, error) {
writers := make([]io.Writer, len(loggerOptions.AdditionalWriters))
copy(writers, loggerOptions.AdditionalWriters)
if loggerOptions.FilePath != "" {
doesFileExist, err := DoesFileExist(loggerOptions.FilePath)
if err != nil {
return nil, err
}
if doesFileExist {
absoluteFilePath, err := filepath.Abs(loggerOptions.FilePath)
if err != nil {
return nil, err
}
return nil, errors.New(fmt.Sprintf("File already exists at %v", absoluteFilePath))
}
file, err := os.Create(loggerOptions.FilePath)
if err != nil {
return nil, err
}
// Close, so we can reopen as write-only
err = file.Close()
if err != nil {
return nil, err
}
file, err = os.OpenFile(loggerOptions.FilePath, os.O_WRONLY, 0)
if err != nil {
return nil, err
}
writers = append(writers, file)
}
if loggerOptions.UseStdout {
writers = append(writers, os.Stdout)
}
writer := newSyncWriter(io.MultiWriter(writers...))
logger := log.New(writer, "", log.LUTC|log.Ldate|log.Ltime|log.Lshortfile)
return logger, nil
}
type syncWriter struct {
mutex *sync.Mutex
writer io.Writer
}
func newSyncWriter(writer io.Writer) io.Writer {
return &syncWriter{&sync.Mutex{}, writer}
}
func (sw *syncWriter) Write(p []byte) (n int, err error) {
sw.mutex.Lock()
n, err = sw.writer.Write(p)
sw.mutex.Unlock()
return n, err
}