WIP request ids + trace context

rpc/rpc_requestid.go

@@ -0,0 +1,58 @@
+package rpc
+
+import (
+	"context"
+	"encoding/base64"
+	"strings"
+
+	"github.com/google/uuid"
+)
+
+type requestIDGenerator struct{}
+
+func newRequestIDGenerator() *requestIDGenerator {
+	return &requestIDGenerator{}
+}
+
+type RequestID struct{ s string }
+
+func (r RequestID) String() string { return r.s }
+
+type requestIDContextKey int
+
+const (
+	requestIDContextKeyRequestID requestIDContextKey = 1 + iota
+)
+
+func (g *requestIDGenerator) newID() RequestID {
+	id := uuid.New()
+	var buf strings.Builder
+	enc := base64.NewEncoder(base64.RawStdEncoding, &buf)
+	n, err := enc.Write(id[:])
+	if err != nil {
+		panic(err)
+	} else if n != len(id) {
+		panic(n)
+	}
+	if err := enc.Close(); err != nil {
+		panic(err)
+	}
+	return RequestID{buf.String()}
+}
+
+func (g *requestIDGenerator) inject(ctx context.Context) context.Context {
+	return context.WithValue(ctx, requestIDContextKeyRequestID, g.newID())
+}
+
+func GetRequestID(ctx context.Context) (id RequestID, ok bool) {
+	id, ok = ctx.Value(requestIDContextKeyRequestID).(RequestID)
+	return id, ok
+}
+
+func MustGetRequestID(ctx context.Context) (id RequestID) {
+	id, ok := GetRequestID(ctx)
+	if !ok {
+		panic("calling context expectes request id to bet set")
+	}
+	return id
+}