gogo/protobuf is deprecated

[johnlanda]

The gogoproto project is deprecated.

I noticed that there is an issue in the etcd repo but wanted to raise this here as well now that raft is in its own repo.

• Protobuf: cleanup both golang/protobuf and gogo/protobuf etcd#14533

It seems like the consensus was to move to google.golang.org/protobuf

[tbg]

Unfortunately, the official protobuf library lacks an equivalent to (gogoproto.nullable). We have a number of non-primitive fields that would then be turned into pointers, which would likely negatively impair the memory efficiency of raft:

raft/raftpb/raft.proto

Lines 70 to 107 in 09c91d8

	message Message {
	optional MessageType type = 1 [(gogoproto.nullable) = false];
	optional uint64 to = 2 [(gogoproto.nullable) = false];
	optional uint64 from = 3 [(gogoproto.nullable) = false];
	optional uint64 term = 4 [(gogoproto.nullable) = false];
	// logTerm is generally used for appending Raft logs to followers. For example,
	// (type=MsgApp,index=100,logTerm=5) means the leader appends entries starting
	// at index=101, and the term of the entry at index 100 is 5.
	// (type=MsgAppResp,reject=true,index=100,logTerm=5) means follower rejects some
	// entries from its leader as it already has an entry with term 5 at index 100.
	// (type=MsgStorageAppendResp,index=100,logTerm=5) means the local node wrote
	// entries up to index=100 in stable storage, and the term of the entry at index
	// 100 was 5. This doesn't always mean that the corresponding MsgStorageAppend
	// message was the one that carried these entries, just that those entries were
	// stable at the time of processing the corresponding MsgStorageAppend.
	optional uint64 logTerm = 5 [(gogoproto.nullable) = false];
	optional uint64 index = 6 [(gogoproto.nullable) = false];
	repeated Entry entries = 7 [(gogoproto.nullable) = false];
	optional uint64 commit = 8 [(gogoproto.nullable) = false];
	// (type=MsgStorageAppend,vote=5,term=10) means the local node is voting for
	// peer 5 in term 10. For MsgStorageAppends, the term, vote, and commit fields
	// will either all be set (to facilitate the construction of a HardState) if
	// any of the fields have changed or will all be unset if none of the fields
	// have changed.
	optional uint64 vote = 13 [(gogoproto.nullable) = false];
	// snapshot is non-nil and non-empty for MsgSnap messages and nil for all other
	// message types. However, peer nodes running older binary versions may send a
	// non-nil, empty value for the snapshot field of non-MsgSnap messages. Code
	// should be prepared to handle such messages.
	optional Snapshot snapshot = 9 [(gogoproto.nullable) = true];
	optional bool reject = 10 [(gogoproto.nullable) = false];
	optional uint64 rejectHint = 11 [(gogoproto.nullable) = false];
	optional bytes context = 12 [(gogoproto.nullable) = true];
	// responses are populated by a raft node to instruct storage threads on how
	// to respond and who to respond to when the work associated with a message
	// is complete. Populated for MsgStorageAppend and MsgStorageApply messages.
	repeated Message responses = 14 [(gogoproto.nullable) = false];
	}

We have the same problem over in https://github.com/cockroachdb/cockroach/. I know we have an issue but I can't find it right now.

This doesn't mean we want to stick with gogoproto forever, just pointing out that it's not trivial.