chore: add backup app

pkg/core/backup/timer/timer.go

@@ -0,0 +1,68 @@
+// Package timer provides ...
+package timer
+
+import (
+	"errors"
+	"strconv"
+	"time"
+
+	"github.com/eiblog/eiblog/pkg/config"
+	"github.com/eiblog/eiblog/pkg/core/backup/timer/qiniu"
+
+	"github.com/sirupsen/logrus"
+)
+
+// Start to backup with ticker
+func Start() error {
+	var storage Storage
+	// backup instance
+	switch config.Conf.BackupApp.BackupTo {
+	case "qiniu":
+		storage = qiniu.Storage{}
+
+	default:
+		return errors.New("timer: unknown backup to driver: " +
+			config.Conf.BackupApp.BackupTo)
+	}
+
+	// parse duration
+	interval, err := ParseDuration(config.Conf.BackupApp.Interval)
+	if err != nil {
+		return err
+	}
+
+	t := time.NewTicker(interval)
+	for now := range t.C {
+		err = storage.BackupData(now)
+		if err != nil {
+			logrus.Error("timer: Start.BackupData: ", now, err)
+		}
+	}
+	return nil
+}
+
+// ParseDuration parse string to duration
+func ParseDuration(d string) (time.Duration, error) {
+	if len(d) == 0 {
+		return 0, errors.New("timer: incorrect duration input")
+	}
+
+	length := len(d)
+	switch d[length-1] {
+	case 's', 'm', 'h':
+		return time.ParseDuration(d)
+	case 'd':
+		di, err := strconv.Atoi(d[:length-1])
+		if err != nil {
+			return 0, err
+		}
+		return time.Duration(di) * time.Hour * 24, nil
+	}
+
+	return 0, errors.New("timer: unsupported duration:" + d)
+}
+
+// Storage backup backend
+type Storage interface {
+	BackupData(now time.Time) error
+}