We are discussing how to create Modern webservices using gRPC and Protocol Buffers in Golang.

1. Creating modern webservices
in
Golang
// Omid Hojabri
// E-mail: o.hojabri@gmail.com
// Skype: hojabri
// LinkedIn: linkedin.com/in/hojabri
using gRPC + Protocol
Buffers

2. REST : Popular API
 REST (HTTP-JSON)
 JSON
 Format in URL:
 GET /api/v1/user/231/roles/453
 POST /api/v1/user/231/roles
 PUT …
 DELETE ...

3. Concerns about APIs
 Data size
 Latency
 Scalability
 Load Balancing
 Communication between languages
 Authentication
 Monitoring
 Logging

4. What is an API
 Is a contract
 Client sends REQUEST
 Server sends RESPONSE

5. gRPC
 Is a free and open-source framework developed by
 Allows to simply define REQUEST and RESPONSE for RPC (Remote Procedure Calls)
 Modern, Fast, Efficient (based on HTTP/2)
 Low latency
 Supports streaming
 Many languages support it
 Authentication, Monitoring, Load balancing and Logging are easy to define with gRPC
 Many companies like Google, Netflix, Square, CoreOS, Spotify, Docker, Cisco,… using it fully.

6. Official supported languages
 C/C++
 Java
 Android Java
 Go
 C#
 Kotlin
 Node.js
 Objective-C
 PHP (Beta)
 Python
 Ruby
 Dart

7. RPC
 Remote Procedure Call
 Client calls functions directly on the server
 gRPC implements RPC very cleanly and it solves a
lot of problems

8. gRPC overview
gRPC uses protocol buffers (protobuf) to communicate between clients and servers

9. How it runs?
 gRPC needs to define messages and services using Protocol
Buffers
 gRPC codes will be generated automatically with “protoc”
command!
 Data is binary
 You need just implementing the methods defined based on your
message type
 Defining Protocol Buffers in .proto files.

10. .proto files
 We define
messages and
service
definitions in
.proto files.
 (API contract)

11. Types of API in gRPC
1 Unary
2 Server Streaming
3 Client Streaming
4 Bi-directional Streaming

12. Unary API
Client Server
Request
Response

13. Server Streaming API
Client Server
Request
Message 1
Message 2
Message 3
Message n
.
.
.
.

14. Client Streaming API
Client Server
Message 1
Message 2
Message 3
Message n
Response
.
.
.
.

15. Bi-directional Streaming API
Client Server
Client Message 1
Client Message 2
Client Message 3
Server Message 3
Server Message 4
Server Message n
Client Message 4
Client Message n
Server Message 2
Server Message 1

16. gRPC vs REST
gRPC REST
Data is binary, smaller and communication is faster (25
more performance based on benchmarks)
Text based, bigger and slower
HTTP/2 (Low latency) HTTP/1.1 (Higher latency)
Unary, Server streaming, Client streaming, bi-
directional streaming
Request – Response only
Any API commands CRUD (Create – Retrieve – Update – Delete) POST –
GET – PUT - DELETE
Code generation by protocol buffers in any language Manual code or by OpenAPI/Swagger
RPC based HTTP words based

17. Installation
 Prerequisites:
 Go to be installed (any one of the three latest major
release)
 Protocol Buffer compiler (protoc v3)
 Go plugin for protocol compiler

18. Protocol Buffer Compiler (v3)
 The protocol buffer compiler (protoc) is used to
compile (code generation) .proto files, which contain
service and message definitions.
 Linux:

 MacOS:


19. Protocol Buffer Compiler (v3)
 Windows:
 Download and install the latest release of binary version
from:
 https://github.com/protocolbuffers/protobuf/releases/tag/v3.13.0
 (at the moment v3.13.0 is released)

20. Go plugin for the protocol
buffers
1 Install the protocol compiler plugin for Go (protoc-gen-go)
using the following command:
2 Update your PATH so that the protoc compiler can find the
plugin:

21. Installing dependencies
 Installing go grpc module: https://github.com/grpc/grpc-
go
 (It may take some time to install completely)

22. Configuration of a .proto file
 Syntax version and package definition:

23. Configuration of a .proto file
 Message definition:

24. Configuration of a .proto file
 Service Definition:

25. Generating Code
 Will generate a file called “greet.pb.go”

26. Server sample code

27. Server sample code

28. Client sample

29. Client sample

30. Full sample source code
 I’ve uploaded my sample source code which covers
all four types of gRPC API
https://github.com/hojabri/grpc-pr

31. Thank you
Github: https://github.com/hojabri
E-mail: o.hojabri@gmail.com
Skype: hojabri
LinkedIn: https://linkedin.com/in/hojabri