Function lockDatabase

backend/server/services/locking.go:36–66

lockDatabase prevents multiple devlake instances from sharing the same lockDatabase check the models.LockingHistory for the detail

()

// lockDatabase prevents multiple devlake instances from sharing the same lockDatabase
// check the models.LockingHistory for the detail
func lockDatabase() {
	db := basicRes.GetDal()
	// first, register the instance
	errors.Must(db.AutoMigrate(&models.LockingHistory{}))
	hostName := errors.Must1(os.Hostname())
	lockingHistory := &models.LockingHistory{
		HostName: hostName,
		Version:  version.Version,
	}
	errors.Must(db.Create(lockingHistory))
	// 2. obtain the lock: using a never released transaction
	// This prevents multiple devlake instances from sharing the same database by locking the migration history table
	// However, it would not work if any older devlake instances were already using the database.
	lockingTx = db.Begin()
	c := make(chan bool, 1)
	go func() {
		errors.Must(lockingTx.DropTables(models.LockingStub{}.TableName()))
		errors.Must(lockingTx.AutoMigrate(&models.LockingStub{}))
		errors.Must(lockingTx.LockTables(dal.LockTables{{Table: "_devlake_locking_stub", Exclusive: true}}))
		lockingHistory.Succeeded = true
		errors.Must(db.Update(lockingHistory))
		c <- true
	}()

	// 3. update the record
	select {
	case <-c:
	case <-time.After(10 * time.Second):
		panic(fmt.Errorf("locking _devlake_locking_stub timeout, the database might be locked by another devlake instance"))
	}
}