| <!-- | |
| Licensed to the Apache Software Foundation (ASF) under one | |
| or more contributor license agreements. See the NOTICE file | |
| distributed with this work for additional information | |
| regarding copyright ownership. The ASF licenses this file | |
| to you under the Apache License, Version 2.0 (the | |
| "License"); you may not use this file except in compliance | |
| with the License. You may obtain a copy of the License at | |
| http://www.apache.org/licenses/LICENSE-2.0 | |
| Unless required by applicable law or agreed to in writing, | |
| software distributed under the License is distributed on an | |
| "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY | |
| KIND, either express or implied. See the License for the | |
| specific language governing permissions and limitations | |
| under the License. | |
| --> | |
| <div align=center><img src=https://docs.google.com/drawings/d/e/2PACX-1vSkTj4ZujX3NOS18gt_xzX6hqobVCDRnpbbVUsWeV7L1-s4xF2Pg8NsFKLGQl---LsE9TzMQUseOtPU/pub?w=990&h=700#NexresRPC> | |
| </div> | |
| NexresRPC Server is a modern high-performance asynchronous IO Remote Procedure Call(RPC) framework that supports any service running in Byzantine Environment. | |
| It provides the capability for any service to connect other services in or out of the same cluster. | |
| NexresRPC contains three components: Acceptor, Service, and ReplicaClient. | |
| * Acceptor runs two types of connections: **Long Connection** that is built between internal services, and **Short Connection** that is connected from the user clients. | |
| * Long Connection uses an Async Acceptor, which uses the [boost::asio](https://www.boost.org/doc/libs/1_79_0/doc/html/boost_asio.html) library as the core io operator, to manage the socket channels. | |
| * Short Connection uses the standard tcp socket library to accept a client request. The client socket information will be passed to the service in case | |
| they need to send messages back to the client. The incoming messages will be pushed into the message input queue(MIQ). | |
| * Service runs multiple workers which keep watching the incoming messages from MIQ, popping and executing. Messages that need to be | |
| delivered to other services will be pushed into the message output queue(MOQ). | |
| * ReplicaClient is also an asnychronous io client which uses the [boost::asio](https://www.boost.org/doc/libs/1_79_0/doc/html/boost_asio.html) library to send out the messages from MOQ as well. Async Replica Client handlers a few | |
| numbers of [boost::io_service](https://www.boost.org/doc/libs/1_66_0/doc/html/boost_asio/reference/io_service.html) so as to fully utilize the IO write. Messages from MOQ will be grouped as one batch to reduce the IO latency. |