diff --git a/raft/log.go b/raft/log.go index 57e902cca..2e853a23a 100644 --- a/raft/log.go +++ b/raft/log.go @@ -84,16 +84,18 @@ func (l *raftLog) append(after uint64, ents ...pb.Entry) uint64 { } // findConflict finds the index of the conflict. -// It returns the the first pair of confilcting entries between the existing -// entries and the given entries, if there is any. +// It returns the first pair of conflicting entries between the existing +// entries and the given entries, if there are any. // If there is no conflicting entries, and the existing entries contains // all the given entries, zero will be returned. // If there is no conflicting entries, but the given entries contains new // entries, the index of the first new entry will be returned. -// Conflicting entries has the same index but different term. -// The first given entry MUST have the index equal to from. -// The index of the given entries MUST be continously increasing. +// An entry is considered to be conflicting if it has the same index but +// a different term. +// The first entry MUST have an index equal to the argument 'from'. +// The index of the given entries MUST be continuously increasing. func (l *raftLog) findConflict(from uint64, ents []pb.Entry) uint64 { + // TODO(xiangli): validate the index of ents for i, ne := range ents { if oe := l.at(from + uint64(i)); oe == nil || oe.Term != ne.Term { return from + uint64(i) @@ -133,7 +135,7 @@ func (l *raftLog) resetNextEnts() { func (l *raftLog) lastIndex() uint64 { return uint64(len(l.ents)) - 1 + l.offset } -func (l raftLog) lastTerm() uint64 { return l.term(l.lastIndex()) } +func (l *raftLog) lastTerm() uint64 { return l.term(l.lastIndex()) } func (l *raftLog) term(i uint64) uint64 { if e := l.at(i); e != nil { @@ -156,7 +158,8 @@ func (l *raftLog) entries(i uint64) []pb.Entry { // by comparing the index and term of the last entries in the existing logs. // If the logs have last entries with different terms, then the log with the // later term is more up-to-date. If the logs end with the same term, then -// whichever log has the larger lastIndex is more up-to-date. +// whichever log has the larger lastIndex is more up-to-date. If the logs are +// the same, the given log is up-to-date. func (l *raftLog) isUpToDate(lasti, term uint64) bool { return term > l.lastTerm() || (term == l.lastTerm() && lasti >= l.lastIndex()) } diff --git a/raft/log_test.go b/raft/log_test.go index a555acda9..3cfa41a31 100644 --- a/raft/log_test.go +++ b/raft/log_test.go @@ -50,7 +50,7 @@ func TestFindConflict(t *testing.T) { for i, tt := range tests { raftLog := newLog() - raftLog.ents = append(raftLog.ents, previousEnts...) + raftLog.append(raftLog.lastIndex(), previousEnts...) gconflict := raftLog.findConflict(tt.from, tt.ents) if gconflict != tt.wconflict { @@ -62,7 +62,7 @@ func TestFindConflict(t *testing.T) { func TestIsUpToDate(t *testing.T) { previousEnts := []pb.Entry{{Term: 1}, {Term: 2}, {Term: 3}} raftLog := newLog() - raftLog.ents = append(raftLog.ents, previousEnts...) + raftLog.append(raftLog.lastIndex(), previousEnts...) tests := []struct { lastIndex uint64 term uint64 @@ -139,7 +139,7 @@ func TestAppend(t *testing.T) { for i, tt := range tests { raftLog := newLog() - raftLog.ents = append(raftLog.ents, previousEnts...) + raftLog.append(raftLog.lastIndex(), previousEnts...) raftLog.unstable = previousUnstable index := raftLog.append(tt.after, tt.ents...) if index != tt.windex { @@ -219,7 +219,7 @@ func TestUnstableEnts(t *testing.T) { for i, tt := range tests { raftLog := newLog() - raftLog.ents = append(raftLog.ents, previousEnts...) + raftLog.append(0, previousEnts...) raftLog.unstable = tt.unstable ents := raftLog.unstableEnts() raftLog.resetUnstable()