重构数据库备份与恢复模块 (#80)

* fix: 保存 LastResult 时截断字符串过长部分，以避免数据库报错

* refactor: 新增 entity.DbTaskBase 和 persistence.dbTaskBase, 用于实现数据库备份和恢复任务处理相关部分

* fix: aeskey变更后，解密密码出现数组越界访问错误

* fix: 时间属性为零值时，保存到 mysql 数据库报错

* refactor db.infrastructure.service.scheduler

* feat: 实现立即备份功能

* refactor db.infrastructure.service.db_instance

* refactor: 从数据库中获取数据库备份目录、mysql文件路径等配置信息

* fix: 数据库备份和恢复问题

* fix: 修改 .gitignore 文件，忽略数据库备份目录和数据库程序目录

server/internal/db/application/db_binlog.go

@@ -0,0 +1,154 @@
+package application
+
+import (
+	"context"
+	"fmt"
+	"mayfly-go/internal/db/domain/entity"
+	"mayfly-go/internal/db/domain/repository"
+	"mayfly-go/pkg/logx"
+	"mayfly-go/pkg/utils/stringx"
+	"mayfly-go/pkg/utils/timex"
+	"sync"
+	"time"
+)
+
+const (
+	binlogDownloadInterval = time.Minute * 15
+)
+
+type DbBinlogApp struct {
+	binlogRepo        repository.DbBinlog
+	binlogHistoryRepo repository.DbBinlogHistory
+	backupRepo        repository.DbBackup
+	backupHistoryRepo repository.DbBackupHistory
+	dbApp             Db
+	context           context.Context
+	cancel            context.CancelFunc
+	waitGroup         sync.WaitGroup
+}
+
+var (
+	binlogResult = map[entity.TaskStatus]string{
+		entity.TaskDelay:    "等待备份BINLOG",
+		entity.TaskReady:    "准备备份BINLOG",
+		entity.TaskReserved: "BINLOG备份中",
+		entity.TaskSuccess:  "BINLOG备份成功",
+		entity.TaskFailed:   "BINLOG备份失败",
+	}
+)
+
+func newDbBinlogApp(repositories *repository.Repositories, dbApp Db) (*DbBinlogApp, error) {
+	ctx, cancel := context.WithCancel(context.Background())
+	svc := &DbBinlogApp{
+		binlogRepo:        repositories.Binlog,
+		binlogHistoryRepo: repositories.BinlogHistory,
+		backupRepo:        repositories.Backup,
+		backupHistoryRepo: repositories.BackupHistory,
+		dbApp:             dbApp,
+		context:           ctx,
+		cancel:            cancel,
+	}
+	svc.waitGroup.Add(1)
+	go svc.run()
+	return svc, nil
+}
+
+func (app *DbBinlogApp) runTask(ctx context.Context, backup *entity.DbBackup) error {
+	if err := app.AddTaskIfNotExists(ctx, entity.NewDbBinlog(backup.DbInstanceId)); err != nil {
+		return err
+	}
+	latestBinlogSequence, earliestBackupSequence := int64(-1), int64(-1)
+	binlogHistory, ok, err := app.binlogHistoryRepo.GetLatestHistory(backup.DbInstanceId)
+	if err != nil {
+		return err
+	}
+	if ok {
+		latestBinlogSequence = binlogHistory.Sequence
+	} else {
+		backupHistory, err := app.backupHistoryRepo.GetEarliestHistory(backup.DbInstanceId)
+		if err != nil {
+			return err
+		}
+		earliestBackupSequence = backupHistory.BinlogSequence
+	}
+	conn, err := app.dbApp.GetDbConnByInstanceId(backup.DbInstanceId)
+	if err != nil {
+		return err
+	}
+	dbProgram := conn.GetDialect().GetDbProgram()
+	binlogFiles, err := dbProgram.FetchBinlogs(ctx, false, earliestBackupSequence, latestBinlogSequence)
+	if err == nil {
+		err = app.binlogHistoryRepo.InsertWithBinlogFiles(ctx, backup.DbInstanceId, binlogFiles)
+	}
+	taskStatus := entity.TaskSuccess
+	if err != nil {
+		taskStatus = entity.TaskFailed
+	}
+	task := &entity.DbBinlog{}
+	task.Id = backup.DbInstanceId
+	return app.updateCurTask(ctx, taskStatus, err, task)
+}
+
+func (app *DbBinlogApp) run() {
+	defer app.waitGroup.Done()
+
+	for !app.closed() {
+		app.fetchFromAllInstances()
+		timex.SleepWithContext(app.context, binlogDownloadInterval)
+	}
+}
+
+func (app *DbBinlogApp) fetchFromAllInstances() {
+	tasks, err := app.backupRepo.ListRepeating()
+	if err != nil {
+		logx.Errorf("DbBinlogApp: 获取数据库备份任务失败: %s", err.Error())
+		return
+	}
+	for _, task := range tasks {
+		if app.closed() {
+			break
+		}
+		if err := app.runTask(app.context, task); err != nil {
+			logx.Errorf("DbBinlogApp: 下载 binlog 文件失败: %s", err.Error())
+			return
+		}
+	}
+}
+
+func (app *DbBinlogApp) Close() {
+	app.cancel()
+	app.waitGroup.Wait()
+}
+
+func (app *DbBinlogApp) closed() bool {
+	return app.context.Err() != nil
+}
+
+func (app *DbBinlogApp) AddTaskIfNotExists(ctx context.Context, task *entity.DbBinlog) error {
+	if err := app.binlogRepo.AddTaskIfNotExists(ctx, task); err != nil {
+		return err
+	}
+	if task.Id == 0 {
+		return nil
+	}
+	return nil
+}
+
+func (app *DbBinlogApp) DeleteTask(ctx context.Context, taskId uint64) error {
+	// todo: 删除 Binlog 历史文件
+	if err := app.binlogRepo.DeleteById(ctx, taskId); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (app *DbBinlogApp) updateCurTask(ctx context.Context, status entity.TaskStatus, lastErr error, task *entity.DbBinlog) error {
+	task.LastStatus = status
+	var result = binlogResult[status]
+	if lastErr != nil {
+		result = fmt.Sprintf("%v: %v", binlogResult[status], lastErr)
+	}
+	task.LastResult = stringx.TruncateStr(result, entity.LastResultSize)
+	task.LastTime = timex.NewNullTime(time.Now())
+	return app.binlogRepo.UpdateById(ctx, task, "last_status", "last_result", "last_time")
+}