Merge pull request #8548 from dgquintas/lb-tokens-length

Made LB token dynamic size <= 50 bytes

src/core/ext/lb_policy/grpclb/grpclb.c

@@ -407,10 +407,12 @@ static grpc_lb_addresses *process_serverlist(
     /* lb token processing */
     void *user_data;
     if (server->has_load_balance_token) {
-      const size_t lb_token_size =
-          GPR_ARRAY_SIZE(server->load_balance_token) - 1;
+      const size_t lb_token_max_length =
+          GPR_ARRAY_SIZE(server->load_balance_token);
+      const size_t lb_token_length =
+          strnlen(server->load_balance_token, lb_token_max_length);
       grpc_mdstr *lb_token_mdstr = grpc_mdstr_from_buffer(
-          (uint8_t *)server->load_balance_token, lb_token_size);
+          (uint8_t *)server->load_balance_token, lb_token_length);
       user_data = grpc_mdelem_from_metadata_strings(GRPC_MDSTR_LB_TOKEN,
                                                     lb_token_mdstr);
     } else {

src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h

@@ -77,7 +77,7 @@ typedef struct _grpc_lb_v1_Server {
     bool has_port;
     int32_t port;
     bool has_load_balance_token;
-    char load_balance_token[65];
+    char load_balance_token[50];
     bool has_drop_request;
     bool drop_request;
 /* @@protoc_insertion_point(struct:grpc_lb_v1_Server) */
@@ -172,7 +172,7 @@ extern const pb_field_t grpc_lb_v1_Server_fields[5];
 #define grpc_lb_v1_LoadBalanceResponse_size      (98 + grpc_lb_v1_ServerList_size)
 #define grpc_lb_v1_InitialLoadBalanceResponse_size 90
 /* grpc_lb_v1_ServerList_size depends on runtime parameters */
-#define grpc_lb_v1_Server_size                   98
+#define grpc_lb_v1_Server_size                   83
 
 /* Message IDs (where set with "msgid" option) */
 #ifdef PB_MSGID

src/proto/grpc/lb/v1/load_balancer.options

@@ -1,6 +1,5 @@
 grpc.lb.v1.InitialLoadBalanceRequest.name max_size:128
-grpc.lb.v1.InitialLoadBalanceResponse.client_config max_size:64
 grpc.lb.v1.InitialLoadBalanceResponse.load_balancer_delegate max_size:64
 grpc.lb.v1.Server.ip_address max_size:16
-grpc.lb.v1.Server.load_balance_token max_size:65
+grpc.lb.v1.Server.load_balance_token max_size:50
 load_balancer.proto no_unions:true

src/proto/grpc/lb/v1/load_balancer.proto

@@ -63,7 +63,8 @@ message LoadBalanceRequest {
 }
 
 message InitialLoadBalanceRequest {
-  // Name of load balanced service (IE, service.grpc.gslb.google.com)
+  // Name of load balanced service (IE, service.grpc.gslb.google.com). Its
+  // length should be less than 256 bytes.
   string name = 1;
 }
 
@@ -95,7 +96,8 @@ message InitialLoadBalanceResponse {
   // This is an application layer redirect that indicates the client should use
   // the specified server for load balancing. When this field is non-empty in
   // the response, the client should open a separate connection to the
-  // load_balancer_delegate and call the BalanceLoad method.
+  // load_balancer_delegate and call the BalanceLoad method. Its length should
+  // be less than 64 bytes.
   string load_balancer_delegate = 1;
 
   // This interval defines how often the client should send the client stats
@@ -130,6 +132,8 @@ message Server {
   // frontend requests for that pick must include the token in its initial
   // metadata. The token is used by the backend to verify the request and to
   // allow the backend to report load to the gRPC LB system.
+  //
+  // Its length is variable but less than 50 bytes.
   string load_balance_token = 3;
 
   // Indicates whether this particular request should be dropped by the client

test/cpp/grpclb/grpclb_test.cc

@@ -144,7 +144,6 @@ static gpr_slice build_response_payload_slice(
     // disfunctional implementation of std::to_string in gcc 4.4, which doesn't
     // have a version for int but does have one for long long int.
     string token_data = "token" + std::to_string((long long int)ports[i]);
-    token_data.resize(64, '-');
     server->set_load_balance_token(token_data);
   }
   const grpc::string &enc_resp = response.SerializeAsString();
@@ -333,7 +332,6 @@ static void start_backend_server(server_fixture *sf) {
     // disfunctional implementation of std::to_string in gcc 4.4, which doesn't
     // have a version for int but does have one for long long int.
     string expected_token = "token" + std::to_string((long long int)sf->port);
-    expected_token.resize(64, '-');
     GPR_ASSERT(contains_metadata(&request_metadata_recv, "lb-token",
                                  expected_token.c_str()));