|
1
|
|
|
package balancer |
|
2
|
|
|
|
|
3
|
|
|
import ( |
|
4
|
|
|
"crypto/rand" |
|
5
|
|
|
"fmt" |
|
6
|
|
|
"log" |
|
7
|
|
|
"math/big" |
|
8
|
|
|
|
|
9
|
|
|
"google.golang.org/grpc/balancer" |
|
10
|
|
|
|
|
11
|
|
|
"github.com/Permify/permify/pkg/consistent" |
|
12
|
|
|
) |
|
13
|
|
|
|
|
14
|
|
|
type picker struct { |
|
15
|
|
|
consistent *consistent.Consistent |
|
16
|
|
|
width int |
|
17
|
|
|
} |
|
18
|
|
|
|
|
19
|
|
|
// Generate a cryptographically secure random index function with resilient error handling |
|
20
|
|
|
var randomIndex = func(max int) int { |
|
21
|
|
|
// Ensure max > 0 to avoid issues |
|
22
|
|
|
if max <= 0 { |
|
23
|
|
|
log.Println("randomIndex: max value is less than or equal to 0, returning 0 as fallback") |
|
24
|
|
|
return 0 |
|
25
|
|
|
} |
|
26
|
|
|
|
|
27
|
|
|
// Use crypto/rand to generate a random index |
|
28
|
|
|
n, err := rand.Int(rand.Reader, big.NewInt(int64(max))) |
|
29
|
|
|
if err != nil { |
|
30
|
|
|
// Log the error and return a deterministic fallback value (e.g., 0) |
|
31
|
|
|
log.Printf("randomIndex: failed to generate a secure random number, returning 0 as fallback: %v", err) |
|
32
|
|
|
return 0 |
|
33
|
|
|
} |
|
34
|
|
|
|
|
35
|
|
|
return int(n.Int64()) |
|
36
|
|
|
} |
|
37
|
|
|
|
|
38
|
|
|
func (p *picker) Pick(info balancer.PickInfo) (balancer.PickResult, error) { |
|
39
|
|
|
// Safely extract the key from the context |
|
40
|
|
|
keyValue := info.Ctx.Value(Key) |
|
41
|
|
|
if keyValue == nil { |
|
42
|
|
|
return balancer.PickResult{}, fmt.Errorf("context key missing") |
|
43
|
|
|
} |
|
44
|
|
|
key, ok := keyValue.([]byte) |
|
45
|
|
|
if !ok { |
|
46
|
|
|
return balancer.PickResult{}, fmt.Errorf("context key is not of type []byte") |
|
47
|
|
|
} |
|
48
|
|
|
|
|
49
|
|
|
// Retrieve the closest N members |
|
50
|
|
|
members, err := p.consistent.ClosestN(key, p.width) |
|
51
|
|
|
if err != nil { |
|
52
|
|
|
return balancer.PickResult{}, fmt.Errorf("failed to get closest members: %v", err) |
|
53
|
|
|
} |
|
54
|
|
|
if len(members) == 0 { |
|
55
|
|
|
return balancer.PickResult{}, fmt.Errorf("no available members") |
|
56
|
|
|
} |
|
57
|
|
|
|
|
58
|
|
|
// Randomly pick one member if width > 1 |
|
59
|
|
|
index := 0 |
|
60
|
|
|
if p.width > 1 { |
|
61
|
|
|
index = randomIndex(p.width) |
|
62
|
|
|
} |
|
63
|
|
|
|
|
64
|
|
|
// Assert the member type |
|
65
|
|
|
chosen, ok := members[index].(ConsistentMember) |
|
66
|
|
|
if !ok { |
|
67
|
|
|
return balancer.PickResult{}, fmt.Errorf("invalid member type: expected subConnMember") |
|
68
|
|
|
} |
|
69
|
|
|
|
|
70
|
|
|
// Return the chosen connection |
|
71
|
|
|
return balancer.PickResult{SubConn: chosen.SubConn}, nil |
|
72
|
|
|
} |
|
73
|
|
|
|
Permify /
permify
