// Prepare send a block to datanode
func (self *DataServer) PrepareSendBlock(param *proc.PrepareBlockParam, lease *proc.CatLease) error {
var nextLease proc.CatLease
var deliverChan chan []byte
nextParam := param.NextPipeParam()
if nextParam != nil {
// if there is another replica
location := nextParam.ServerLocation()
nextDataServer := self.pool.DataServer(location)
// prepare next data server
err := nextDataServer.PrepareSendBlock(nextParam, &nextLease)
if err != nil {
return err
}
// prepare deliverChan block to next data server
nextBlockClient := self.pool.NewBlockClient(location)
deliverChan = make(chan []byte)
go nextBlockClient.SendBlock(deliverChan, nextLease.ID)
}
writeDiskChan := make(chan []byte, DEFAULT_CHAN_SIZE)
done := make(chan bool, 1)
// init the lease
lease.New()
self.leaseMap[lease.ID] = lease
self.pipelineMap[lease.ID] = NewPipelineParam(&nextLease, nextParam)
trans := NewReadTransaction(lease.ID, done, deliverChan, writeDiskChan)
go self.writeBlockToDisk(writeDiskChan, param.Block)
// init data receiver
self.blockServer.StartTransaction(trans)
return nil
}
func NewPipelineParam(lease *proc.CatLease, param *proc.PrepareBlockParam) *PipelineParam {
p := &PipelineParam{
lease: lease,
}
if param != nil {
p.location = param.ServerLocation()
}
return p
}