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Commit f6233a1

Browse files
add token range example in the distributed-db playground
1 parent 883f407 commit f6233a1

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1 file changed

+87
-16
lines changed
  • mutexes/distributed-db/playground/tokens

1 file changed

+87
-16
lines changed

‎mutexes/distributed-db/playground/tokens/main.go‎

Lines changed: 87 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -10,23 +10,59 @@ import (
1010
)
1111

1212
func main() {
13-
tokens := NewTokens(5, 256)
14-
for i := 0; i < 50; i++ {
13+
nodes := []Node{
14+
{
15+
ID: 1,
16+
Name: "server1",
17+
Address: "localhost:8081",
18+
},
19+
{
20+
ID: 2,
21+
Name: "server2",
22+
Address: "localhost:8082",
23+
},
24+
{
25+
ID: 3,
26+
Name: "server3",
27+
Address: "localhost:8083",
28+
},
29+
{
30+
ID: 4,
31+
Name: "server4",
32+
Address: "localhost:8084",
33+
},
34+
{
35+
ID: 5,
36+
Name: "server5",
37+
Address: "localhost:8085",
38+
},
39+
}
40+
tokens := NewTokens(nodes, 256)
41+
42+
newNode := Node{
43+
ID: 6,
44+
Name: "server6",
45+
Address: "localhost:8086",
46+
}
47+
tokens.AddNode(newNode)
48+
49+
for i := 0; i < 1000; i++ {
1550
key := fmt.Sprintf("k%d", i+1)
1651
sum := hash(key)
17-
fmt.Println(key, sum, tokens.Get(sum))
52+
fmt.Println(key, sum, tokens.GetNode(sum).Name)
1853
}
1954
}
2055

21-
func NewTokens(numberOfNodes, numberOfTokenRanges int) Tokens {
22-
servers := make([]string, numberOfNodes)
23-
tokenRange := math.MaxInt / numberOfNodes / numberOfTokenRanges
56+
func NewTokens(nodes []Node, numberOfTokenRanges int) Tokens {
57+
numberOfNodes := len(nodes)
58+
tokenRange := uint64(math.MaxInt / numberOfNodes / numberOfTokenRanges)
2459
ranges := make([]uint64, 0, numberOfNodes*numberOfTokenRanges)
60+
nodesMap := map[int]Node{}
2561
for i := 0; i < numberOfNodes; i++ {
26-
servers[i] = fmt.Sprintf("server%d", i+1)
62+
nodesMap[nodes[i].ID] = nodes[i]
2763
for j := numberOfTokenRanges * i; j < numberOfTokenRanges*(i+1); j++ {
28-
r := tokenRange * (j + 1)
29-
ranges = append(ranges, uint64(r))
64+
r := tokenRange * uint64(j + 1)
65+
ranges = append(ranges, r)
3066
}
3167
}
3268

@@ -36,9 +72,9 @@ func NewTokens(numberOfNodes, numberOfTokenRanges int) Tokens {
3672
randomRanges[i], randomRanges[j] = randomRanges[j], randomRanges[i]
3773
})
3874

39-
i, mappings := 0, map[uint64]string{}
75+
i, mappings := 0, map[uint64]int{}
4076
for _, r := range randomRanges {
41-
mappings[r] = servers[i]
77+
mappings[r] = nodes[i].ID
4278
i++
4379
if i == numberOfNodes {
4480
i = 0
@@ -48,20 +84,55 @@ func NewTokens(numberOfNodes, numberOfTokenRanges int) Tokens {
4884
tokens := Tokens{
4985
Ranges: ranges,
5086
Mappings: mappings,
87+
Nodes: nodesMap,
88+
NumberOfTokenRanges: numberOfTokenRanges,
5189
}
5290
return tokens
5391
}
5492

5593
type Tokens struct {
56-
Ranges []uint64
57-
Mappings map[uint64]string
94+
Ranges []uint64
95+
Mappings map[uint64]int
96+
Nodes map[int]Node
97+
NumberOfTokenRanges int
98+
rangeMax uint64
5899
}
59100

60-
func (t *Tokens) Get(n uint64) string {
101+
func (t *Tokens) GetNode(token uint64) Node {
61102
idx := sort.Search(len(t.Ranges)-1, func(i int) bool {
62-
return t.Ranges[i] >= n
103+
return t.Ranges[i] >= token
63104
})
64-
return t.Mappings[t.Ranges[idx]]
105+
nodeID := t.Mappings[t.Ranges[idx]]
106+
return t.Nodes[nodeID]
107+
}
108+
109+
func (t *Tokens) AddNode(node Node) {
110+
t.Nodes[node.ID] = node
111+
tokenRange := uint64(math.MaxInt / len(t.Nodes) / t.NumberOfTokenRanges)
112+
newRanges := make([]uint64, 0, t.NumberOfTokenRanges)
113+
for i := 0; i < len(t.Ranges)+t.NumberOfTokenRanges; i++ {
114+
if i < len(t.Ranges) {
115+
r := t.Ranges[i]
116+
decrement := r - tokenRange*(uint64(i+1))
117+
newRange := r - decrement
118+
srv := t.Mappings[r]
119+
120+
delete(t.Mappings, r)
121+
t.Mappings[newRange] = srv
122+
t.Ranges[i] = newRange
123+
} else {
124+
newRange := tokenRange * uint64(i+1)
125+
t.Mappings[newRange] = len(t.Nodes)
126+
newRanges = append(newRanges, newRange)
127+
}
128+
}
129+
t.Ranges = append(t.Ranges, newRanges...)
130+
}
131+
132+
type Node struct {
133+
ID int
134+
Name string
135+
Address string
65136
}
66137

67138
func hash(s string) uint64 {

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