84 lines
2.1 KiB
Go
84 lines
2.1 KiB
Go
package logx
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import (
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"errors"
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"io"
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"os"
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"path/filepath"
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"sync"
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"gopkg.in/natefinch/lumberjack.v2"
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)
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// RotationConfig opts a file logger into size-based rotation. Zero limits use
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// 100 MiB, 10 backups and 7 days. Each file must have a single process owner.
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type RotationConfig struct {
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Enabled bool `json:"enabled"`
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MaxSizeMB int `json:"maxSizeMb"`
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MaxBackups int `json:"maxBackups"`
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MaxAgeDays int `json:"maxAgeDays"`
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Compress bool `json:"compress"`
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}
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func (r RotationConfig) validate(cfg Config) error {
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if r.MaxSizeMB < 0 || r.MaxSizeMB > 1024*1024 || r.MaxBackups < 0 || r.MaxBackups > 10000 || r.MaxAgeDays < 0 || r.MaxAgeDays > 36500 {
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return errors.New("logx: invalid rotation limits")
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}
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if r.Enabled && (cfg.File == "" || cfg.Writer != nil) {
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return errors.New("logx: rotation requires a file and no custom writer")
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}
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return nil
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}
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func rotatingWriter(cfg Config) (io.Writer, func() error, error) {
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r := cfg.Rotation
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if r.MaxSizeMB == 0 {
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r.MaxSizeMB = 100
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}
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if r.MaxBackups == 0 {
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r.MaxBackups = 10
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}
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if r.MaxAgeDays == 0 {
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r.MaxAgeDays = 7
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}
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if err := os.MkdirAll(filepath.Dir(cfg.File), 0700); err != nil {
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return nil, nil, err
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}
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// Fail at setup, rather than silently dropping the first log record.
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f, err := os.OpenFile(cfg.File, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0600)
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if err != nil {
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return nil, nil, err
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}
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if err = f.Close(); err != nil {
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return nil, nil, err
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}
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w := &rotationWriter{writer: &lumberjack.Logger{Filename: cfg.File, MaxSize: r.MaxSizeMB, MaxBackups: r.MaxBackups, MaxAge: r.MaxAgeDays, Compress: r.Compress}}
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return w, w.Close, nil
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}
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// Lumberjack can reopen after Close; prevent children of a closed logger from
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// resurrecting its file. The lock also serializes shutdown with pending writes.
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type rotationWriter struct {
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mu sync.Mutex
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writer *lumberjack.Logger
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closed bool
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}
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func (w *rotationWriter) Write(p []byte) (int, error) {
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w.mu.Lock()
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defer w.mu.Unlock()
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if w.closed {
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return 0, io.ErrClosedPipe
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}
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return w.writer.Write(p)
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}
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func (w *rotationWriter) Close() error {
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w.mu.Lock()
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defer w.mu.Unlock()
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if w.closed {
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return nil
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}
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w.closed = true
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return w.writer.Close()
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}
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