// SendBatch implements Sender.
// TODO(tschottdorf): We actually don't want to chop EndTransaction off for
// single-range requests (but that happens now since EndTransaction has the
// isAlone flag). Whether it is one or not is unknown right now (you can only
// find out after you've sent to the Range/looked up a descriptor that suggests
// that you're multi-range. In those cases, the wrapped sender should return an
// error so that we split and retry once the chunk which contains
// EndTransaction (i.e. the last one).
func (cs *chunkingSender) SendBatch(ctx context.Context, ba proto.BatchRequest) (*proto.BatchResponse, error) {
if len(ba.Requests) < 1 {
panic("empty batch")
}
// Deterministically create ClientCmdIDs for all parts of the batch if
// a CmdID is already set (otherwise, leave them empty).
var nextID func() proto.ClientCmdID
empty := proto.ClientCmdID{}
if empty == ba.CmdID {
nextID = func() proto.ClientCmdID {
return empty
}
} else {
rng := rand.New(rand.NewSource(ba.CmdID.Random))
id := ba.CmdID
nextID = func() proto.ClientCmdID {
curID := id // copy
id.Random = rng.Int63() // adjust for next call
return curID
}
}
parts := ba.Split()
var rplChunks []*proto.BatchResponse
for _, part := range parts {
ba.Requests = part
ba.CmdID = nextID()
rpl, err := cs.f(ctx, ba)
if err != nil {
return nil, err
}
// Propagate transaction from last reply to next request. The final
// update is taken and put into the response's main header.
ba.Txn.Update(rpl.Header().Txn)
rplChunks = append(rplChunks, rpl)
}
reply := rplChunks[0]
for _, rpl := range rplChunks[1:] {
reply.Responses = append(reply.Responses, rpl.Responses...)
}
reply.ResponseHeader = rplChunks[len(rplChunks)-1].ResponseHeader
reply.Txn = ba.Txn
return reply, nil
}