Add proxy <-> management authentication

proxy/internal/grpc/auth.go

@@ -0,0 +1,48 @@
+// Package grpc provides gRPC utilities for the proxy client.
+package grpc
+
+import (
+	"context"
+	"os"
+	"strconv"
+
+	log "github.com/sirupsen/logrus"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
+)
+
+// EnvProxyAllowInsecure controls whether the proxy token can be sent over non-TLS connections.
+const EnvProxyAllowInsecure = "NB_PROXY_ALLOW_INSECURE"
+
+var _ credentials.PerRPCCredentials = (*proxyAuthToken)(nil)
+
+type proxyAuthToken struct {
+	token         string
+	allowInsecure bool
+}
+
+func (t proxyAuthToken) GetRequestMetadata(context.Context, ...string) (map[string]string, error) {
+	return map[string]string{
+		"authorization": "Bearer " + t.token,
+	}, nil
+}
+
+// RequireTransportSecurity returns true by default to protect the token in transit.
+// Set NB_PROXY_ALLOW_INSECURE=true to allow non-TLS connections (not recommended for production).
+func (t proxyAuthToken) RequireTransportSecurity() bool {
+	return !t.allowInsecure
+}
+
+// WithProxyToken returns a DialOption that sets the proxy access token on each outbound RPC.
+func WithProxyToken(token string) grpc.DialOption {
+	allowInsecure := false
+	if val := os.Getenv(EnvProxyAllowInsecure); val != "" {
+		parsed, err := strconv.ParseBool(val)
+		if err != nil {
+			log.Warnf("invalid value for %s: %v", EnvProxyAllowInsecure, err)
+		} else {
+			allowInsecure = parsed
+		}
+	}
+	return grpc.WithPerRPCCredentials(proxyAuthToken{token: token, allowInsecure: allowInsecure})
+}