feat: complete API-driven projects with infrastructure and business acceptance

logx/rotation.go

@@ -0,0 +1,83 @@
+package logx
+
+import (
+	"errors"
+	"io"
+	"os"
+	"path/filepath"
+	"sync"
+
+	"gopkg.in/natefinch/lumberjack.v2"
+)
+
+// RotationConfig opts a file logger into size-based rotation. Zero limits use
+// 100 MiB, 10 backups and 7 days. Each file must have a single process owner.
+type RotationConfig struct {
+	Enabled    bool `json:"enabled"`
+	MaxSizeMB  int  `json:"maxSizeMb"`
+	MaxBackups int  `json:"maxBackups"`
+	MaxAgeDays int  `json:"maxAgeDays"`
+	Compress   bool `json:"compress"`
+}
+
+func (r RotationConfig) validate(cfg Config) error {
+	if r.MaxSizeMB < 0 || r.MaxSizeMB > 1024*1024 || r.MaxBackups < 0 || r.MaxBackups > 10000 || r.MaxAgeDays < 0 || r.MaxAgeDays > 36500 {
+		return errors.New("logx: invalid rotation limits")
+	}
+	if r.Enabled && (cfg.File == "" || cfg.Writer != nil) {
+		return errors.New("logx: rotation requires a file and no custom writer")
+	}
+	return nil
+}
+
+func rotatingWriter(cfg Config) (io.Writer, func() error, error) {
+	r := cfg.Rotation
+	if r.MaxSizeMB == 0 {
+		r.MaxSizeMB = 100
+	}
+	if r.MaxBackups == 0 {
+		r.MaxBackups = 10
+	}
+	if r.MaxAgeDays == 0 {
+		r.MaxAgeDays = 7
+	}
+	if err := os.MkdirAll(filepath.Dir(cfg.File), 0700); err != nil {
+		return nil, nil, err
+	}
+	// Fail at setup, rather than silently dropping the first log record.
+	f, err := os.OpenFile(cfg.File, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0600)
+	if err != nil {
+		return nil, nil, err
+	}
+	if err = f.Close(); err != nil {
+		return nil, nil, err
+	}
+	w := &rotationWriter{writer: &lumberjack.Logger{Filename: cfg.File, MaxSize: r.MaxSizeMB, MaxBackups: r.MaxBackups, MaxAge: r.MaxAgeDays, Compress: r.Compress}}
+	return w, w.Close, nil
+}
+
+// Lumberjack can reopen after Close; prevent children of a closed logger from
+// resurrecting its file. The lock also serializes shutdown with pending writes.
+type rotationWriter struct {
+	mu     sync.Mutex
+	writer *lumberjack.Logger
+	closed bool
+}
+
+func (w *rotationWriter) Write(p []byte) (int, error) {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	if w.closed {
+		return 0, io.ErrClosedPipe
+	}
+	return w.writer.Write(p)
+}
+func (w *rotationWriter) Close() error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	if w.closed {
+		return nil
+	}
+	w.closed = true
+	return w.writer.Close()
+}