2.6版本不包含 max_body_size ，无法调整brpc max_body_size，导致报错

[noahdyp]

bug描述 Describe the Bug

E1130 16:30:07.186429 75 baidu_rpc_protocol.cpp:118] body_size=109507652 from 192.168.142.57:58816 is too large
E1130 16:30:07.186448 75 input_messenger.cpp:139] A message from 192.168.142.57:58816(protocol=baidu_std) is bigger than 67108864 bytes, the connection will be closed. Set max_body_size to allow bigger messages

其他补充信息 Additional Supplementary Information

No response

[noahdyp]

解决思路：

1. 用动态库暴露brpc 的 gflags参数
2. python中显示更新max_body_size

`
echo '
#include <gflags/gflags.h>
#include <pybind11/pybind11.h>

namespace brpc {
DECLARE_uint64(max_body_size);
}

namespace py = pybind11;

PYBIND11_MODULE(brpc_flags, m) {
m.def("get_max_body_size", {
return brpc::FLAGS_max_body_size;
}, "A function that returns the max body size.");

m.def("set_max_body_size", [](int64_t new_size) {
    brpc::FLAGS_max_body_size = new_size;
}, "A function that sets the max body size.");

}' > brpc_flags.cc
`

[noahdyp]

bug描述 Describe the Bug

E1130 16:30:07.186429 75 baidu_rpc_protocol.cpp:118] body_size=109507652 from 192.168.142.57:58816 is too large E1130 16:30:07.186448 75 input_messenger.cpp:139] A message from 192.168.142.57:58816(protocol=baidu_std) is bigger than 67108864 bytes, the connection will be closed. Set max_body_size to allow bigger messages

其他补充信息 Additional Supplementary Information

No response