Expose the received_us of RPC to users

Author: liupengs

src/brpc/controller.cpp

@@ -298,6 +298,7 @@ void Controller::ResetPods() {
     _response_streams.clear();
     _remote_stream_settings = NULL;
     _auth_flags = 0;
+    _rpc_received_us = 0;
 }
 
 Controller::Call::Call(Controller::Call* rhs)

src/brpc/controller.h

@@ -638,6 +638,17 @@ friend void policy::ProcessThriftRequest(InputMessageBase*);
         return _response_content_type;
     }
 
+    // If brpc acts as a server, this interface exposes the time when the RPC was received from the
+    // socket. This function can be used in scenarios where the user code needs to understand the RPC
+    // reception time, such as for precise control of timeouts. Users will require timing to start
+    // from the receipt of the RPC. When the user processing function starts to handle the RPC, if
+    // it is found that the RPC has timed out, it will be directly discarded
+    void set_rpc_received_us(int64_t received_us) { _rpc_received_us = received_us; }
+
+    // Get the received time of RPC (in microseconds), if the returned value is 0, it means that
+    // the received time of RPC is not recorded in the controller.
+    int64_t get_rpc_received_us() const { return _rpc_received_us; }
+
 private:
     struct CompletionInfo {
         CallId id;           // call_id of the corresponding request
@@ -909,6 +920,9 @@ friend void policy::ProcessThriftRequest(InputMessageBase*);
     uint32_t _auth_flags;
 
     AfterRpcRespFnType _after_rpc_resp_fn;
+
+    // The point in time when the rpc is read from the socket
+    int64_t _rpc_received_us;
 };
 
 // Advises the RPC system that the caller desires that the RPC call be

src/brpc/policy/baidu_rpc_protocol.cpp

@@ -615,6 +615,7 @@ void ProcessRpcRequest(InputMessageBase* msg_base) {
     cntl->set_request_content_type(meta.content_type());
     cntl->set_request_compress_type((CompressType)meta.compress_type());
     cntl->set_request_checksum_type((ChecksumType)meta.checksum_type());
+    cntl->set_rpc_received_us(msg->received_us());
     accessor.set_checksum_value(meta.checksum_value());
     accessor.set_server(server)
         .set_security_mode(security_mode)
@@ -943,6 +944,7 @@ void ProcessRpcResponse(InputMessageBase* msg_base) {
         }
     }
 
+    cntl->set_rpc_received_us(msg->received_us());
     Span* span = accessor.span();
     if (span) {
         span->set_base_real_us(msg->base_real_us());