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b757e1bc87
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.
78 lines
2.1 KiB
Go
78 lines
2.1 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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"testing"
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"github.com/cockroachdb/datadriven"
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"go.etcd.io/etcd/raft/v3/raftpb"
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)
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func (env *InteractionEnv) handleStabilize(t *testing.T, d datadriven.TestData) error {
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idxs := nodeIdxs(t, d)
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return env.Stabilize(idxs...)
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}
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// Stabilize repeatedly runs Ready handling on and message delivery to the set
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// of nodes specified via the idxs slice until reaching a fixed point.
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func (env *InteractionEnv) Stabilize(idxs ...int) error {
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var nodes []Node
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for _, idx := range idxs {
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nodes = append(nodes, env.Nodes[idx])
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}
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if len(nodes) == 0 {
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nodes = env.Nodes
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}
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for {
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done := true
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for _, rn := range nodes {
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if rn.HasReady() {
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done = false
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idx := int(rn.Status().ID - 1)
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fmt.Fprintf(env.Output, "> %d handling Ready\n", idx+1)
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env.withIndent(func() { env.ProcessReady(idx) })
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}
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}
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for _, rn := range nodes {
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id := rn.Status().ID
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// NB: we grab the messages just to see whether to print the header.
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// DeliverMsgs will do it again.
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if msgs, _ := splitMsgs(env.Messages, id); len(msgs) > 0 {
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fmt.Fprintf(env.Output, "> %d receiving messages\n", id)
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env.withIndent(func() { env.DeliverMsgs(Recipient{ID: id}) })
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done = false
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}
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}
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if done {
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return nil
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}
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}
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}
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func splitMsgs(msgs []raftpb.Message, to uint64) (toMsgs []raftpb.Message, rmdr []raftpb.Message) {
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// NB: this method does not reorder messages.
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for _, msg := range msgs {
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if msg.To == to {
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toMsgs = append(toMsgs, msg)
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} else {
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rmdr = append(rmdr, msg)
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}
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}
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return toMsgs, rmdr
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}
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