mirror of
https://github.com/etcd-io/etcd.git
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0544f33248
Apps typically maintain the raft configuration as part of the state machine. As a result, they want to be able to reject configuration change entries at apply time based on the state on which the entry is supposed to be applied. When this happens, the app should not call ApplyConfChange, but the comments did not make this clear. As a result, it was tempting to pass an empty pb.ConfChange or it's V2 version instead of not calling ApplyConfChange. However, an empty V1 or V2 proto aren't noops when the configuration is joint: an empty V1 change is treated internally as a single configuration change for NodeID zero and will cause a panic when applied in a joint state. An empty V2 proto is treated as a signal to leave a joint state, which means that the app's config and raft's would diverge. The comments updated in this commit now ask users to not call ApplyConfState when they reject a conf change. Apps that never use joint consensus can keep their old behavior since the distinction only matters when in a joint state, but we don't want to encourage that.
95 lines
2.4 KiB
Go
95 lines
2.4 KiB
Go
// Copyright 2019 The etcd Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package rafttest
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import (
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"fmt"
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"strconv"
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"testing"
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"github.com/cockroachdb/datadriven"
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"go.etcd.io/etcd/raft"
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"go.etcd.io/etcd/raft/raftpb"
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)
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func (env *InteractionEnv) handleDeliverMsgs(t *testing.T, d datadriven.TestData) error {
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var rs []Recipient
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for _, arg := range d.CmdArgs {
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if len(arg.Vals) == 0 {
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id, err := strconv.ParseUint(arg.Key, 10, 64)
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if err != nil {
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t.Fatal(err)
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}
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rs = append(rs, Recipient{ID: id})
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}
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for i := range arg.Vals {
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switch arg.Key {
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case "drop":
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var id uint64
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arg.Scan(t, i, &id)
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var found bool
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for _, r := range rs {
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if r.ID == id {
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found = true
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}
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}
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if found {
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t.Fatalf("can't both deliver and drop msgs to %d", id)
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}
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rs = append(rs, Recipient{ID: id, Drop: true})
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}
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}
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}
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if n := env.DeliverMsgs(rs...); n == 0 {
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env.Output.WriteString("no messages\n")
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}
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return nil
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}
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type Recipient struct {
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ID uint64
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Drop bool
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}
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// DeliverMsgs goes through env.Messages and, depending on the Drop flag,
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// delivers or drops messages to the specified Recipients. Returns the
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// number of messages handled (i.e. delivered or dropped). A handled message
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// is removed from env.Messages.
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func (env *InteractionEnv) DeliverMsgs(rs ...Recipient) int {
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var n int
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for _, r := range rs {
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var msgs []raftpb.Message
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msgs, env.Messages = splitMsgs(env.Messages, r.ID)
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n += len(msgs)
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for _, msg := range msgs {
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if r.Drop {
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fmt.Fprint(env.Output, "dropped: ")
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}
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fmt.Fprintln(env.Output, raft.DescribeMessage(msg, defaultEntryFormatter))
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if r.Drop {
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// NB: it's allowed to drop messages to nodes that haven't been instantiated yet,
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// we haven't used msg.To yet.
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continue
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}
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toIdx := int(msg.To - 1)
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if err := env.Nodes[toIdx].Step(msg); err != nil {
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fmt.Fprintln(env.Output, err)
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}
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}
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}
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return n
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}
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