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
|
package nodeid
import (
"context"
"fmt"
"os"
"github.com/cespare/xxhash/v2"
middleware "github.com/grpc-ecosystem/go-grpc-middleware/v2"
"github.com/rs/zerolog/log"
"google.golang.org/grpc"
)
const spiceDBPrefix = "spicedb:"
type ctxKeyType struct{}
var nodeIDKey ctxKeyType = struct{}{}
type nodeIDHandle struct {
nodeID string
}
var defaultNodeID string
func init() {
hostname, err := os.Hostname()
if err != nil {
log.Warn().Err(err).Msg("failed to get hostname, using an empty node ID")
return
}
// Hash the hostname to get the final default node ID.
hasher := xxhash.New()
if _, err := hasher.WriteString(hostname); err != nil {
log.Warn().Err(err).Msg("failed to hash hostname, using an empty node ID")
return
}
defaultNodeID = spiceDBPrefix + fmt.Sprintf("%x", hasher.Sum(nil))
}
// ContextWithHandle adds a placeholder to a context that will later be
// filled by the Node ID.
func ContextWithHandle(ctx context.Context) context.Context {
return context.WithValue(ctx, nodeIDKey, &nodeIDHandle{})
}
// FromContext reads the node's ID out of a context.Context.
func FromContext(ctx context.Context) (string, error) {
if c := ctx.Value(nodeIDKey); c != nil {
handle := c.(*nodeIDHandle)
if handle.nodeID != "" {
return handle.nodeID, nil
}
}
if err := setInContext(ctx, defaultNodeID); err != nil {
return "", err
}
return defaultNodeID, nil
}
// setInContext adds a node ID to the given context
func setInContext(ctx context.Context, nodeID string) error {
handle := ctx.Value(nodeIDKey)
if handle == nil {
return nil
}
handle.(*nodeIDHandle).nodeID = nodeID
return nil
}
// UnaryServerInterceptor returns a new unary server interceptor that adds the
// node ID to the context. If empty, spicedb:$hostname is used.
func UnaryServerInterceptor(nodeID string) grpc.UnaryServerInterceptor {
return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
newCtx := ContextWithHandle(ctx)
if nodeID != "" {
if err := setInContext(newCtx, nodeID); err != nil {
return nil, err
}
}
return handler(newCtx, req)
}
}
// StreamServerInterceptor returns a new stream server interceptor that adds the
// node ID to the context. If empty, spicedb:$hostname is used.
func StreamServerInterceptor(nodeID string) grpc.StreamServerInterceptor {
return func(srv interface{}, stream grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
wrapped := middleware.WrapServerStream(stream)
wrapped.WrappedContext = ContextWithHandle(wrapped.WrappedContext)
if nodeID != "" {
if err := setInContext(wrapped.WrappedContext, nodeID); err != nil {
return err
}
}
return handler(srv, wrapped)
}
}
|
