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This commit creates a new probe_and_replicate.txt interactive test. The test creates a complete Raft log configuration and demonstrates how a leader probes and replicates to each of its followers. The log configuration constructed is identical to the one present in Figure 7 of the raft paper (https://raft.github.io/raft.pdf), which looks like: ``` 1 2 3 4 5 6 7 8 9 10 11 12 n1: [1][1][1][4][4][5][5][6][6][6] n2: [1][1][1][4][4][5][5][6][6] n3: [1][1][1][4] n4: [1][1][1][4][4][5][5][6][6][6][6] n5: [1][1][1][4][4][5][5][6][7][7][7][7] n6: [1][1][1][4][4][4][4] n7: [1][1][1][2][2][2][3][3][3][3][3] ``` Once in this state, we then elect node 1 as the leader and stabilize the entire raft group. This demonstrates how a newly elected leader probes for matching indexes, overwrites conflicting entries, and catches up all followers. This will be useful to demonstrate the impact of more efficient probing behavior.
104 lines
2.6 KiB
Go
104 lines
2.6 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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"bufio"
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"fmt"
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"math"
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"strings"
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"go.etcd.io/etcd/raft/v3"
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pb "go.etcd.io/etcd/raft/v3/raftpb"
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)
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// InteractionOpts groups the options for an InteractionEnv.
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type InteractionOpts struct {
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OnConfig func(*raft.Config)
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}
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// Node is a member of a raft group tested via an InteractionEnv.
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type Node struct {
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*raft.RawNode
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Storage
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Config *raft.Config
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History []pb.Snapshot
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}
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// InteractionEnv facilitates testing of complex interactions between the
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// members of a raft group.
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type InteractionEnv struct {
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Options *InteractionOpts
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Nodes []Node
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Messages []pb.Message // in-flight messages
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Output *RedirectLogger
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}
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// NewInteractionEnv initializes an InteractionEnv. opts may be nil.
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func NewInteractionEnv(opts *InteractionOpts) *InteractionEnv {
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if opts == nil {
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opts = &InteractionOpts{}
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}
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return &InteractionEnv{
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Options: opts,
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Output: &RedirectLogger{
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Builder: &strings.Builder{},
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},
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}
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}
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func (env *InteractionEnv) withIndent(f func()) {
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orig := env.Output.Builder
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env.Output.Builder = &strings.Builder{}
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f()
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scanner := bufio.NewScanner(strings.NewReader(env.Output.Builder.String()))
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for scanner.Scan() {
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orig.WriteString(" " + scanner.Text() + "\n")
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}
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env.Output.Builder = orig
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}
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// Storage is the interface used by InteractionEnv. It is comprised of raft's
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// Storage interface plus access to operations that maintain the log and drive
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// the Ready handling loop.
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type Storage interface {
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raft.Storage
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SetHardState(state pb.HardState) error
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ApplySnapshot(pb.Snapshot) error
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Compact(newFirstIndex uint64) error
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Append([]pb.Entry) error
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}
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// defaultRaftConfig sets up a *raft.Config with reasonable testing defaults.
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// In particular, no limits are set.
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func defaultRaftConfig(id uint64, applied uint64, s raft.Storage) *raft.Config {
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return &raft.Config{
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ID: id,
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Applied: applied,
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ElectionTick: 3,
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HeartbeatTick: 1,
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Storage: s,
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MaxSizePerMsg: math.MaxUint64,
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MaxInflightMsgs: math.MaxInt32,
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}
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}
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func defaultEntryFormatter(b []byte) string {
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return fmt.Sprintf("%q", b)
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}
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