etcd/contrib/raftexample/raft_test.go
Nathan VanBenschoten 0f9d7a4f95 raft: make Message.Snapshot nullable, halve struct size
This commit makes the rarely used `raftpb.Message.Snapshot` field nullable.
In doing so, it reduces the memory size of a `raftpb.Message` message from
264 bytes to 128 bytes — a 52% reduction in size.

While this commit does not change the protobuf encoding, it does change
how that encoding is used. `(gogoproto.nullable) = false` instruct the
generated proto marshaling logic to always encode a value for the field,
even if that value is empty. `(gogoproto.nullable) = true` instructs the
generated proto marshaling logic to omit an encoded value for the field
if the field is nil.

This raises compatibility concerns in both directions. Messages encoded
by new binary versions without a `Snapshot` field will be decoded as an
empty field by old binary versions. In other words, old binary versions
can't tell the difference. However, messages encoded by old binary versions
with an empty Snapshot field will be decoded as a non-nil, empty field by
new binary versions. As a result, new binary versions need to be prepared
to handle such messages.

While Message.Snapshot is not intentionally part of the external interface
of this library, it was possible for users of the library to access it and
manipulate it. As such, this change may be considered a breaking change.

Signed-off-by: Nathan VanBenschoten <nvanbenschoten@gmail.com>
2022-11-09 17:35:52 +00:00

131 lines
2.8 KiB
Go

// Copyright 2022 The etcd Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package main
import (
"reflect"
"testing"
"go.etcd.io/etcd/raft/v3/raftpb"
)
func TestProcessMessages(t *testing.T) {
cases := []struct {
name string
confState raftpb.ConfState
InputMessages []raftpb.Message
ExpectedMessages []raftpb.Message
}{
{
name: "only one snapshot message",
confState: raftpb.ConfState{
Voters: []uint64{2, 6, 8, 10},
},
InputMessages: []raftpb.Message{
{
Type: raftpb.MsgSnap,
To: 8,
Snapshot: &raftpb.Snapshot{
Metadata: raftpb.SnapshotMetadata{
Index: 100,
Term: 3,
ConfState: raftpb.ConfState{
Voters: []uint64{2, 6, 8},
AutoLeave: true,
},
},
},
},
},
ExpectedMessages: []raftpb.Message{
{
Type: raftpb.MsgSnap,
To: 8,
Snapshot: &raftpb.Snapshot{
Metadata: raftpb.SnapshotMetadata{
Index: 100,
Term: 3,
ConfState: raftpb.ConfState{
Voters: []uint64{2, 6, 8, 10},
},
},
},
},
},
},
{
name: "one snapshot message and one other message",
confState: raftpb.ConfState{
Voters: []uint64{2, 7, 8, 12},
},
InputMessages: []raftpb.Message{
{
Type: raftpb.MsgSnap,
To: 8,
Snapshot: &raftpb.Snapshot{
Metadata: raftpb.SnapshotMetadata{
Index: 100,
Term: 3,
ConfState: raftpb.ConfState{
Voters: []uint64{2, 6, 8},
AutoLeave: true,
},
},
},
},
{
Type: raftpb.MsgApp,
From: 6,
To: 8,
},
},
ExpectedMessages: []raftpb.Message{
{
Type: raftpb.MsgSnap,
To: 8,
Snapshot: &raftpb.Snapshot{
Metadata: raftpb.SnapshotMetadata{
Index: 100,
Term: 3,
ConfState: raftpb.ConfState{
Voters: []uint64{2, 7, 8, 12},
},
},
},
},
{
Type: raftpb.MsgApp,
From: 6,
To: 8,
},
},
},
}
for _, tc := range cases {
t.Run(tc.name, func(t *testing.T) {
rn := &raftNode{
confState: tc.confState,
}
outputMessages := rn.processMessages(tc.InputMessages)
if !reflect.DeepEqual(outputMessages, tc.ExpectedMessages) {
t.Fatalf("Unexpected messages, expected: %v, got %v", tc.ExpectedMessages, outputMessages)
}
})
}
}