Presentation at NetPonto community: "We’re going to discuss gRPC, Google’s open-source RPC framework. I’ll dive a bit into the history of RPC as a protocol, and what its historical use has been. I’ll also highlight some benefits to adopt gRPC and how its possible to swap out parts of gRPC and still take advantage of gRPC’s benefits. Finally I’ll answer the question that has been on many lips since gRPC was announced — what does this mean for REST?"

1. gRPC
RPC rebirth?

2. About me
◦ Luís Barbosa
◦ bymyslf@GitHub

3. HTTP API’s in the microservices world

4. HTTP API Paradigms
◦ RPC (gRPC)
◦ REST (HTTP + JSON)
◦ “Query language” (GraphQL)

5. HTTP API Paradigms
◦ RPC (gRPC)
◦ REST (HTTP + JSON)
◦ “Query language” (GraphQL)

6. [API Paradigms] - RPC vs REST
◦ RPC
▫ exposes operations as a method for acting upon data
◦ REST
▫ exposes data as resources to be acted upon
It’s a matter of context/use case!

7. [API Paradigm] - RPC
◦ Origination
◦ Marshaling
◦ Broadcast
◦ Reception
◦ Unmarshaling
◦ Response

8. [API Paradigm] - REST
◦ Client-Server
◦ Stateless
◦ Cacheable
◦ Layered
◦ Code on demand (optional)
◦ Uniform Interface
▫ Identification of resources
▫ Manipulation of resources
▫ Self-descriptive messages
▫ Hypermedia as the engine of application state
(HATEOAS)

9. [API Paradigms] - Some use cases
◦ RPC
▫ Truly microscopic services
▫ Remote system execute/events/commands
▫ Inside bounded context or organization
◦ REST
▫ Public/Client facing API
▫ Manipulating the domain
▫ Crosses bounded context/organization

10. What is gRPC?

11. “
A high performance, open-source
universal RPC framework

12. 'g' stands for something different every gRPC release
◦ 1.0 'g' stands for 'gRPC'
◦ 1.1 'g' stands for 'good'
◦ 1.2 'g' stands for 'green'
◦ 1.3 'g' stands for 'gentle'
◦ 1.4 'g' stands for 'gregarious'
◦ 1.6 'g' stands for 'garcia'
◦ 1.7 'g' stands for 'gambit'
◦ 1.8 'g' stands for 'generous'
◦ 1.9 'g' stands for 'glossy'
◦ 1.10 'g' stands for 'glamorous'
◦ 1.11 'g' stands for 'gorgeous'
◦ 1.12 'g' stands for 'glorious'
◦ 1.13 'g' stands for 'gloriosa'
◦ 1.14 'g' stands for 'gladiolus'
◦ 1.15 'g' stands for 'glider'
◦ 1.16 'g' stands for 'gao'

13. Building a
Cache Service

14. IDL
Interface Definition Language

15. [IDL] - service.proto

16. [IDL] - 1 file 10 languages
◦ C++
◦ Java (includes Android)
◦ Python
◦ Go
◦ Ruby
◦ C#
◦ Node.js
◦ Objective-C
◦ PHP
◦ Dart (Beta)
◦ Web (Beta)

17. Server

18. [Server] - Server.cs

19. Client

20. [Client] - Client.cs

21. How does this work in production?

22. gRPC on the wire
◦ HTTP/2
◦ Protocol Buffers serialization by default
◦ Clients open one long-lived connection to the server
▫ A new HTTP/2 stream for each call
▫ Allows simultaneous in-flight calls
◦ Allows bidirectional streaming
▫ Server-side streaming
▫ Client-side streaming

23. gRPC implementations
◦ 4 high-performance event-loop driven implementations
◦ C
▫ C#, Ruby, Python, node.js, Objective-C, C++ (C core
bindings)
▫ PHP (PECL extension)
◦ Java
◦ Go
◦ Dart (beta)

24. Service Implementation

25. [Service] - CacheService.cs

26. Error Handling

27. [Service] - Error handling

28. [Service] - Error handling types
◦ Client
◦ Server
◦ Both
◦ Never generated by the library

29. Error handling - examples

30. New requirement
Correlation ID

31. Metadata
gRPC “headers”

32. [Metadata] - Client.cs

33. [Metadata] - Server.cs

34. [Metadata] - ServerCallContextExtensions.cs

35. Interceptors
gRPC “middleware”

36. [Interceptors] - Types
◦ Client-side
◦ Server-side
◦ Inherit from Interceptor base class

37. [Interceptors] - CorrelationIdInterceptor.cs

38. [Interceptors] - Client.cs

39. [Interceptors] - Server.cs

40. Secure Transport

41. [Secure] - gRPC Authentication
◦ SSL/TLS
▫ Authenticate server
▫ Encrypt data exchange client-server
◦ Token-based
▫ Google credentials (pluggable)
◦ Authentication API
▫ Channel credentials
▫ Call credentials

42. [Secure] - Credentials.cs

43. [Secure] - Server.cs

44. [Secure] - Client.cs

45. New Feature
Get by key pattern

46. [GetByKeyPattern] - service.proto

47. Out of Memory!!!

48. Streaming

49. [Streaming] - service.proto

50. [Streaming] - CacheServiceImpl.cs

51. [Streaming] - Client.cs

52. Advanced Feature
Support JSON

53. [JSON] - Serializer.cs

54. [JSON] - Messages.cs

55. [JSON] - Descriptors.cs

56. [JSON] - Server.cs

57. It’s done! We did it!

58. And the not so good parts...

59. The not so good parts
◦ Load Balancing
◦ Limited error handling
◦ Support for browser js still beta
◦ Breaking API changes
◦ Poor documentation for some languages
◦ No standardization across languages

60. Show me the code
@GitHub gRPC-Cache-Service

61. Q&A

62. “ Thank you