func()

in store/cluster.go [198:232]

• 31 lines of code
• 9 McCabe index (conditional complexity)

func (cluster *Cluster) MigrateSlot(ctx context.Context, slot SlotRange, targetShardIdx int, slotOnly bool) error {
	if targetShardIdx < 0 || targetShardIdx >= len(cluster.Shards) {
		return consts.ErrIndexOutOfRange
	}
	sourceShardIdx, err := cluster.findShardIndexBySlot(slot)
	if err != nil {
		return err
	}
	if sourceShardIdx == targetShardIdx {
		return consts.ErrShardIsSame
	}
	if slotOnly {
		cluster.Shards[sourceShardIdx].SlotRanges = RemoveSlotFromSlotRanges(cluster.Shards[sourceShardIdx].SlotRanges, slot)
		cluster.Shards[targetShardIdx].SlotRanges = AddSlotToSlotRanges(cluster.Shards[targetShardIdx].SlotRanges, slot)
		return nil
	}

	if cluster.Shards[sourceShardIdx].IsMigrating() || cluster.Shards[targetShardIdx].IsMigrating() {
		return consts.ErrShardSlotIsMigrating
	}
	// Send the migration command to the source node
	sourceMasterNode := cluster.Shards[sourceShardIdx].GetMasterNode()
	if sourceMasterNode == nil {
		return consts.ErrNotFound
	}
	targetNodeID := cluster.Shards[targetShardIdx].GetMasterNode().ID()
	if err := sourceMasterNode.MigrateSlot(ctx, slot, targetNodeID); err != nil {
		return err
	}

	// Will start the data migration in the background
	cluster.Shards[sourceShardIdx].MigratingSlot = &slot
	cluster.Shards[sourceShardIdx].TargetShardIndex = targetShardIdx
	return nil
}