Raft

etcd-raft 有关 log 的实现在分布在log.go，log_unstable.go，storage.go 三个文件中。首先看一下 raftLog 结构体。 raftLog 结构体 type raftLog struct { // storage contains all stable entries since the last snapshot. storage Storage // unstable contains all unstable entries and snapshot. // they will be saved into storage. unstable unstable // committed is the highest log position that is known to be in // stable storage on a quorum of nodes. committed uint64 // applied is the highest log position that the application has // been instructed to apply to its state machine....

首先看一下 raft node 之间传递的基本消息（比如 leader 选举，AppendLog）类型 Message protobuf 定义 message Message { optional MessageType type = 1 ; optional uint64 to = 2 ; optional uint64 from = 3 ; // 整个消息发出去时，所处的任期 optional uint64 term = 4 ; // logTerm is generally used for appending Raft logs to followers. For example, // (type=MsgApp,index=100,logTerm=5) means leader appends entries starting at // index=101, and the term of entry at index 100 is 5....