RPC remote procedure call

RPC brief introduction

RPC, English full name : Remote Procedure Call. Chinese name : Remote procedure call , It is a computer communication protocol . With the help of RPC You can call remote services as if they were local services . For example, two servers, order server and commodity server , The order server needs to call the method of product details , Because the two applications are not in the same memory space , Can't call directly , Therefore, it is necessary to express the semantics of the call and convey the data of the call through the network . It should be noted that RPC Not specific technology , It refers to the process of remote call of the whole network

RPC Four core components

Client( client ), The caller of the service .
Client Stub( Client stub ), Store the address message of the server , Then package the request parameters of the client into network messages , And then send it to the server remotely through the network .
Server( Server side ), The real provider of services .
Server Stub( Server stub ), Receive messages from clients , Send message to Jaguar , And call local methods .

1. client (client) In local call mode ( That is, in the way of interface ) Call the service ;
2. Client stub (client stub) After receiving the call , Be responsible for putting methods 、 The parameters are assembled into a message body capable of network transmission
   ( Serialize the message body object to binary );
3. Client pass socket Send the message to the server ;
4. Server stub ( server stub) Decode the message upon receipt ( Deserialize message object );
5. Server stub ( server stub) The local service is invoked based on the decoding results ;
6. Service handling ( Business processing )
7. The local service executes and returns the result to the server stub ( server stub);
8. Server stub ( server stub) Package the returned results into messages ( Serialize result message object );
9. Server side (server) adopt socket Send a message to the client ;
10. Client stub (client stub) Received result message , And decode it ( Serialize the result message );
11. client (client) Get the final result .

RPC The goal is to 2,3,4,5,7,8,9,10 These steps are encapsulated , only 1,6,11
Duboo,Feign,gRPC All belong to RPC frame

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