gRPC intro workshop

Agenda

  • About RPC
  • RPC vs REST
  • Introduction to gRPC
  • Implementing a gRPC service
  • Advanced features
  • When to use gRPC?
  • Alternatives

Code samples

https://github.com/sagikazarmark/grpc-intro-workshop

About RPC

Definition 🤔

[…] a computer program causes a procedure (subroutine) to execute in a different address space (commonly on another computer on a shared network), which is coded as if it were a normal (local) procedure call, without the programmer explicitly coding the details for the remote interaction

Wikipedia

Definition

  • in a different address space → someone else’s computer
  • normal (local) procedure call → interface
  • no details for the remote interaction → implementation

Source

Interface Definition Language

  • a language for describing communication
  • programming language agnostic
  • serves as a contract for RPC APIs

RPC vs REST

RPC REST
Operates on procedures
(“function calls”)		 resources
Underlying protocol unspecified primarily HTTP
Interactions protocol encapsulated HTTP is part of the contract
  • RPC is more suitable for APIs describing actions (vs resources)
  • RPC has better type-safety guarantees
  • RPC is more strict
  • REST may be more performant when operating on large amount of data

RPC example in HTTP

POST /sayHello HTTP/1.1
Host: api.example.com
Content-Type: application/json

{
  "userId": 1
}

REST example

GET /users/1/greeting HTTP/1.1
Host: api.example.com

Introduction to gRPC

About gRPC

  • High performance
  • Language agnostic (supported languages)
  • Uses http/2 transport
  • Bi-directional streaming
  • Pluggable auth, tracing, load balancing and health checking

Source

IDL: Protocol Buffers

  • Interface Definition Language
  • Message format (binary serialization)
  • Code generation framework

Example 1: Protocol Buffers

Implementing a gRPC service

Example 2: Service definition and server implementation

Example 3: Using the client stub

RPC lifecycle

  • Unary RPC
  • Server streaming RPC
  • Client streaming RPC
  • Bidirectional streaming RPC

Example 4: Server streaming RPC

Advanced features

Example 5: Authentication and error handling

Interceptors

  • Act as middlewares during the request lifecycle
  • Server vs Client
  • Unary vs Stream

Example 6: Server unary interceptor

When to use gRPC?

With great power comes great responsibility

  • API operates on actions instead of resources
  • When efficient communication is a goal
  • In polyglot environments
  • No need for supporting a wide range of clients
  • Internal APIs

whisper microservices

gRPC weaknesses

  • Limited web/browser support
  • Not human-readable format (more difficult to debug)
  • Steeper learning curve

Alternatives

Twirp

Developed at Twitch as a lightweight alternative to gRPC.


https://github.com/twitchtv/twirp


Read the announcement blog post.

Connect

A gRPC-compatible framework with an emphasis on browser- and web-compatibility (from the creators of Buf).


https://connect.build/

The End

Any questions?

Further reading

  • https://grpc.io/
  • https://protobuf.dev/
  • https://github.com/grpc-ecosystem