我们要实现的peer.go中函数接受*pb.Message类型的消息，消息定义在fabric.pb.go中
type Message struct {
Type Message_Type
Timestamp *google_protobuf.Timestamp
Payload []byte
Signature []byte
}
其中Type为消息类型，其值为uint类型，Timestamp为时间戳，Payload为消息内容的编码，Signature为签名。
Payload消息内容编码之前有一下几种类型：
type Message_RequestBatch struct {
RequestBatch *RequestBatch
}
type Message_PrePrepare struct {
PrePrepare *PrePrepare
}
type Message_Prepare struct {
Prepare *Prepare
}
type Message_Commit struct {
Commit *Commit
}
type Message_Checkpoint struct {
Checkpoint *Checkpoint
}
type Message_ViewChange struct {
ViewChange *ViewChange
}
type Message_NewView struct {
NewView *NewView
}
type Message_FetchRequestBatch struct {
FetchRequestBatch *FetchRequestBatch
}
type Message_ReturnRequestBatch struct {
ReturnRequestBatch *RequestBatch
}
1、RequestBatch类型的 batch.go 145行：给出Payload和Type
func (op *obcBatch) broadcastMsg(msg *BatchMessage) {
msgPayload, _ := proto.Marshal(msg)
ocMsg := &pb.Message{
Type: pb.Message_CONSENSUS,
Payload: msgPayload,
}
op.broadcaster.Broadcast(ocMsg)
}
batch.go 135行：Payload取自这儿
func (op *obcBatch) submitToLeader(req *Request) events.Event {
...
op.broadcastMsg(&BatchMessage{Payload: &BatchMessage_Request{Request: req}})
...
}
batch.go 445行：打包成批
func (op *obcBatch) wrapMessage(msgPayload []byte) *pb.Message {
batchMsg := &BatchMessage{Payload: &BatchMessage_PbftMessage{PbftMessage: msgPayload}}
packedBatchMsg, _ := proto.Marshal(batchMsg)
ocMsg := &pb.Message{
Type: pb.Message_CONSENSUS,
Payload: packedBatchMsg,
}
return ocMsg
}
2、Preprepare类型的 pbft-core 659行：此处获得Payload
func (instance *pbftCore) sendPrePrepare(reqBatch *RequestBatch, digest string) {
...
instance.seqNo = n
preprep := &PrePrepare{
View: instance.view,
SequenceNumber: n,
BatchDigest: digest,
RequestBatch: reqBatch,
ReplicaId: instance.id,
}
cert := instance.getCert(instance.view, n)
cert.prePrepare = preprep
cert.digest = digest
instance.innerBroadcast(&Message{Payload: &Message_PrePrepare{PrePrepare: preprep}})
...
}
batch.go 445行：对Payload进行进一步的包装并给出消息类型Type
func (op *obcBatch) wrapMessage(msgPayload []byte) *pb.Message {
batchMsg := &BatchMessage{Payload: &BatchMessage_PbftMessage{PbftMessage: msgPayload}}
packedBatchMsg, _ := proto.Marshal(batchMsg)
ocMsg := &pb.Message{
Type: pb.Message_CONSENSUS,
Payload: packedBatchMsg,
}
return ocMsg
}
3、Prepare、commit、Checkpoint、ViewChange类型的和Preprepare消息产生的过程类似，
pbft-core.go 693行 recvPrePrepare方法中获得Prepare类型的Payload，
pbft-core.go 798行 maybeSendCommit方法中获得commit类型的Payload，
pbft-core.go 958行 Checkpoint方法中获得checkpoint类型的Payload，
viewchange.go 125行 sendViewChange方法中获得ViewChange类型的Payload，和对消息的签名，
viewchange.go 257行 sendNewView方法中获得NewView类型的Payload，
pbft-core.go 1222行 fetchRequestBatches方法中获得FetchRequestBatch类型的Payload，
然后都是经过一系列的调用后经过wrapMessage对Payload进行进一步的包装并给出消息类型Type。