forked from itsnitigya/noise
-
Notifications
You must be signed in to change notification settings - Fork 0
/
iterator.go
180 lines (138 loc) · 3.71 KB
/
iterator.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
package kademlia
import (
"context"
"github.com/perlin-network/noise"
"go.uber.org/zap"
"sync"
"time"
)
// Iterator represents a S/Kademlia overlay network iterator over all peers that may be discovered in the network. It
// is used for peer discovery, and for finding peers by their public key over an overlay network.
type Iterator struct {
sync.Mutex
node *noise.Node
table *Table
logger *zap.Logger
visited map[noise.PublicKey]struct{}
results chan noise.ID
buckets [][]noise.ID
maxNumResults int
numParallelLookups int
numParallelRequestsPerLookup int
lookupTimeout time.Duration
}
// NewIterator instantiates a new overlay network iterator bounded to a node and routing table that may be
// optionally configured with a variadic list of functional options.
func NewIterator(node *noise.Node, table *Table, opts ...IteratorOption) *Iterator {
it := &Iterator{
node: node,
table: table,
logger: node.Logger(),
maxNumResults: BucketSize,
numParallelLookups: 3,
numParallelRequestsPerLookup: 8,
lookupTimeout: 3 * time.Second,
}
for _, opt := range opts {
opt(it)
}
return it
}
// Find attempts to salvage through the Kademlia overlay network through the peers of the node this iterator
// is bound to for a target public key. It blocks the current goroutine until the search is complete.
func (it *Iterator) Find(target noise.PublicKey) []noise.ID {
var closest []noise.ID
it.init(target)
go it.iterate()
for id := range it.results {
closest = append(closest, id)
}
closest = SortByDistance(target, closest)
if len(closest) > it.maxNumResults {
closest = closest[:it.maxNumResults]
}
return closest
}
func (it *Iterator) init(target noise.PublicKey) {
it.results = make(chan noise.ID, 1)
it.visited = map[noise.PublicKey]struct{}{
it.node.ID().ID: {},
target: {},
}
it.buckets = make([][]noise.ID, it.numParallelLookups)
for i, id := range it.table.Peers() {
it.visited[id.ID] = struct{}{}
it.buckets[i%it.numParallelLookups] = append(it.buckets[i%it.numParallelLookups], id)
}
}
func (it *Iterator) iterate() {
var wg sync.WaitGroup
wg.Add(len(it.buckets))
for i := 0; i < len(it.buckets); i++ {
i := i
go func() {
defer wg.Done()
it.processLookupBucket(i)
}()
}
wg.Wait()
close(it.results)
}
func (it *Iterator) processLookupBucket(i int) {
queue := make(chan noise.ID, it.numParallelRequestsPerLookup)
results := make(chan []noise.ID, it.numParallelRequestsPerLookup)
pending := 0
var wg sync.WaitGroup
wg.Add(it.numParallelRequestsPerLookup)
for i := 0; i < it.numParallelRequestsPerLookup; i++ {
go func() {
defer wg.Done()
it.processLookupRequests(queue, results)
}()
}
for {
for len(it.buckets[i]) > 0 && len(queue) < cap(queue) {
popped := it.buckets[i][0]
it.buckets[i] = it.buckets[i][1:]
queue <- popped
pending++
}
if pending == 0 {
break
}
ids := <-results
it.Lock()
for _, id := range ids {
if _, visited := it.visited[id.ID]; !visited {
it.visited[id.ID] = struct{}{}
it.buckets[i] = append(it.buckets[i], id)
}
}
it.Unlock()
pending--
}
close(queue)
wg.Wait()
close(results)
}
func (it *Iterator) processLookupRequests(in <-chan noise.ID, out chan<- []noise.ID) {
for id := range in {
it.lookupRequest(id, out)
}
}
func (it *Iterator) lookupRequest(id noise.ID, out chan<- []noise.ID) {
ctx, cancel := context.WithTimeout(context.Background(), it.lookupTimeout)
defer cancel()
obj, err := it.node.RequestMessage(ctx, id.Address, FindNodeRequest{Target: id.ID})
if err != nil {
out <- nil
return
}
res, ok := obj.(FindNodeResponse)
if !ok {
out <- nil
return
}
it.results <- id
out <- res.Results
}