gRPC-Java

What is gRPC?

• gRPC is a high-performance open-source feature-rich RPC framework

• gRPC is originally developed by Google

• Now it is a part of the Cloud Native Computing Foundation - CNCF

• RPC stands for Remote Procedure Calls

What is Remote Procedure Calls?

• it is a protocol that allows a program to

  • execute a procedure of another program located in other computer

  • without the deveoper explicity coding the details for the remote interaction

• in the client code ,it looks like we’re just calling a function of the server code directly

How gRPC works?

• Client has a fenerated stub that provides the same methods as the server

• the stub calls gRPC framework under the hood to exchange information over netwoek

• Client and server user stubs to interact with each other, so they only need to implement their core service logic

How stubs are generated?

• API contracts description

  • The service and paload messages are defined using Protocol Buffer

• Server and client stubs are generated by the

  • Protocol Buffer compiler

  • gRPC plugins of each language

Why gRPC uses Protocol Buffer?

• Human-readable Interface Degintion Language(IDL)

• Programming languages interoperable:

  • Code generators for many languages

• Binary data representation

  • Smaller size

  • Faster to transport

  • More efficient to serialize / deserialize

• Strongly typed contract

• Conventions for API evolation

  • Backward & forward compatibility

• Alternative options

  • Google faltbuffers

  • Microsoft bond

What languages are supported by gRPC?

• 10 officially supported languages

  • pure implementation:Go,Java,NodeJs

  • Wrap C-gRPC core:C/C++,C#,Objective-C Python ,Ruby,Dart,PHP

• Many other unofficial libraries: Swift,Rust ,TypeScript,Haskell,etc.

What makes gRPC efficient?

GRPC Uses HTTP/2 as its transfer protocol

• Binary framing

  • More performant and robust

  • Lighter to transpot, safer to decode

  • Great combination with Protocol Buffer

• Header compression using HPACK

  • Reduce overhead and improve performance

• multiplexing

  • Send multiple requests and responses in parallel over a single TCP connection

  • reduce latency and improve network utilization

• Server push

  • One client request ,multiple responses

  • Reduce round-trip latency

How HTTP/2 works under the hood

• single TCP connection carries multiple bidirectional streams

• Each stream has a unique ID and caries multiple bidirectional messages

• Each message (request/response) is broken down into multiple binary frames

• Frame is the smallest unit that carries different types of data: HEADERS, SETTINGS, PRIORITY,DATA,etc.

• Frame from different streams are interleaved and then reassembled on the other side

Where gRPC is well suited to?

• Microservice

  • Low latency and high throughput communication

  • Strong API contract

• Polyglot environments

  • Code generation out of the box for many languages

• Point-to-point realtime communication

  • Excellent support for bidirectional streaming

• Network constrained environments

  • Lightweight message format

What will we do?

• install Java Development Kit

• install Intellij IDEA

• Setup a new Gradle project

  • install pluhins for protobuf and gRPC

  • Config automatic code generation upon build

• Use Protobuf options to customise generated hava codes

to be continued