1// Copyright 2019 The etcd Authors
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package rafttest
16
17import (
18	"bufio"
19	"fmt"
20	"strings"
21	"testing"
22
23	"github.com/cockroachdb/datadriven"
24	"go.etcd.io/etcd/raft/raftpb"
25)
26
27func (env *InteractionEnv) handleStabilize(t *testing.T, d datadriven.TestData) error {
28	var idxs []int
29	for _, id := range ints(t, d) {
30		idxs = append(idxs, id-1)
31	}
32	return env.Stabilize(idxs...)
33}
34
35// Stabilize repeatedly runs Ready handling on and message delivery to the set
36// of nodes specified via the idxs slice until reaching a fixed point.
37func (env *InteractionEnv) Stabilize(idxs ...int) error {
38	var nodes []Node
39	for _, idx := range idxs {
40		nodes = append(nodes, env.Nodes[idx])
41	}
42	if len(nodes) == 0 {
43		nodes = env.Nodes
44	}
45
46	withIndent := func(f func()) {
47		orig := env.Output.Builder
48		env.Output.Builder = &strings.Builder{}
49		f()
50
51		scanner := bufio.NewScanner(strings.NewReader(env.Output.Builder.String()))
52		for scanner.Scan() {
53			orig.WriteString("  " + scanner.Text() + "\n")
54		}
55		env.Output.Builder = orig
56	}
57
58	for {
59		done := true
60		for _, rn := range nodes {
61			if rn.HasReady() {
62				done = false
63				idx := int(rn.Status().ID - 1)
64				fmt.Fprintf(env.Output, "> %d handling Ready\n", idx+1)
65				withIndent(func() { env.ProcessReady(idx) })
66			}
67		}
68		for _, rn := range nodes {
69			id := rn.Status().ID
70			// NB: we grab the messages just to see whether to print the header.
71			// DeliverMsgs will do it again.
72			if msgs, _ := splitMsgs(env.Messages, id); len(msgs) > 0 {
73				fmt.Fprintf(env.Output, "> %d receiving messages\n", id)
74				withIndent(func() { env.DeliverMsgs(Recipient{ID: id}) })
75				done = false
76			}
77		}
78		if done {
79			return nil
80		}
81	}
82}
83
84func splitMsgs(msgs []raftpb.Message, to uint64) (toMsgs []raftpb.Message, rmdr []raftpb.Message) {
85	// NB: this method does not reorder messages.
86	for _, msg := range msgs {
87		if msg.To == to {
88			toMsgs = append(toMsgs, msg)
89		} else {
90			rmdr = append(rmdr, msg)
91		}
92	}
93	return toMsgs, rmdr
94}
95