My personal note on gRPC

Basic Concepts

• gRPC is a rpc(protocol) framework.
• Protocol Buffer is serialization mechanism supported by
  • IDL(Interface Definition Language) to write .proto file(scheme file) with
  • protoc(protocol buffer compiler) which can autogenerate client code & server code
  • Libraries which is used with afformentioned autogenerated scripts

Steps to use gRPC

1. Write .proto file
   • with IDL
2. Autogenerate client code & server code with $grpc-gen-grpc (, which is protoc command for ruby). This creates 2 files, which are
   • xxx_pb.rb(Request class and Response class are defined)
   • xxx_services_pb.rb(Service class and Stub class are defined)
3. Implement server script (Server class should implemented here)&client script (which uses Stub class)` and boot them.

Technologies behind gRPC

Protocol Buffers

• As is mentinoned, this is composed of lang + compiler + libraries.
• For ruby, compiler command is protoc-gen-grpc which provides:
  • plugin to autogenerate message class
  • plugin to autogenerate service class
• Its binary format is compact and quickly (de)serializable.

HTTP/2

• Stems from SPDY from Google. Transport is totally updated from HTTP/1.1
• Main functionalities are:
  • Multiplexing(多重化) which enables parallel responding (by multiple streams).
  • Header Compression(ヘッダ圧縮) by HPACK. (Originally in HTTP/1, header was 500-800 bytes)

References

• https://www.wantedly.com/companies/wantedly/post_articles/219429