gRPC or REST, why not both?

While writing microservices you have to make a choice, REST or gRPC (https://grpc.io). While REST has been the norm for writing microservices for quite some time, gRPC is replacing it. But what if one wants their services to be available as both a REST and a gRPC service. In this session, I will show you how you can realize this. In addition to this, I will also show how you document your REST APIs.

Participants can have a look at https://grpc.io to know what gRPC is.
No resources are required.
Expected outcome - Attendees will have an idea about what gRPC is and how to write gRPC and REST services from a single codebase.

Transcript

1. gRPC or REST Why not both? @m_m_murad
2. Mohammad Murad Backend and Mobile engineer
3. Agenda
4. Agenda • What is REST?
5. Agenda • What is REST? • Disadvantages of REST.
6. Agenda • What is REST? • Disadvantages of REST. • What is gRPC?
7. Agenda • What is REST? • Disadvantages of REST. • What is gRPC? • Advantages of gRPC.
8. Agenda • What is REST? • Disadvantages of REST. • What is gRPC? • Advantages of gRPC. • gRPC and REST services from a single codebase.
9. REST
10. REST • Representational State Transfer.
11. REST • Representational State Transfer. • Not a protocol but an Design Pattern.
12. REST • Representational State Transfer. • Not a protocol but an Design Pattern. • Uses HTTP protocol.
13. REST • Representational State Transfer. • Not a protocol but an Design Pattern. • Uses HTTP protocol. • Objects that are send or saved are called resources.
14. REST • Representational State Transfer. • Not a protocol but an Design Pattern. • Uses HTTP protocol. • Objects that are send or saved are called resources. • Operations are described by HTTP verbs.
15. REST • Representational State Transfer. • Not a protocol but an Design Pattern. • Uses HTTP protocol. • Objects that are send or saved are called resources. • Operations are described by HTTP verbs. • Transfers data as XML or JSON or Protocol Buffers.
16. A REST API can be -
17. A REST API can be - XML + HTTP
18. A REST API can be - XML + HTTP JSON + HTTP
19. A REST API can be - XML + HTTP JSON + HTTP Protocol Buffers + HTTP
20. XML + HTTP JSON + HTTP Protocol Buffers + HTTP
21. What does a REST call look like?
22. Is this a REST call? GET http://0.0.0.0:8081/updateBook Content-Type: application/json Authorization: Basic asfd34hk82hg32j== { "id": 12, "author": "Prem" }
23. PUT http://0.0.0.0:8081/books Content-Type: application/json Authorization: Basic asfd34hk82hg32j== { "id": 12, "author": "Prem" } RESTish
24. RESTful API PUT http://0.0.0.0:8081/api/v1/books/12 Content-Type: application/json Authorization: Basic asfd34hk82hg32j== { "author": "Prem" }
25. Disadvantages of REST?
26. Disadvantages of REST? • The data being transferred is heavily bloated.
27. { "id": 12, "name": "Developing in Node", "author": "Prem Pratap Tomar", "rating": 3.2, "release_date": "2019-06-17T19:12:43.905Z", "units_sold": 123456, "publisher": "Leaf publications", "best_sell": true } Bloated data
28. { "id": 12, "name": "Developing in Node", "author": "Prem Pratap Tomar", "rating": 3.2, "release_date": "2019-06-17T19:12:43.905Z", "units_sold": 123456, "publisher": "Leaf publications", "best_sell": true } Message size - 190 bytes (Ignoring the white spaces) Bloated data
29. { "id": 12, "name": "Developing in Node", "author": "Prem Pratap Tomar", "rating": 3.2, "release_date": "2019-06-17T19:12:43.905Z", "units_sold": 123456, "publisher": "Leaf publications", "best_sell": true } Message size - 190 bytes (Ignoring the white spaces) Useful info - 107 bytes (56.3%) Unnecessary info describing useful info - 83 bytes (43.7%) Bloated data
30. {"books":[{"id": 12,"name":"Developing in Node", "author":"Prem Pratap Tomar","rating":3.2,"release_date": "2019-06-17T19:12:43.905Z", "units_sold":1 23456,"publisher":"Leaf publications", "best_sell":true},{"id":13,"name":"Developing in Node","author":"Prem Pratap Tomar","rating":3.2,"release_date": "2019-06-17T19:12:43.930Z", "units_sold":1 23456,"publisher":"Leaf publications", "best_sell":true},{"id":14,"name":"Developing in Node","author":"Prem Pratap Tomar","rating":3.2,"release_date": "2019-06-17T19:12:43.955Z", "units_sold":1 23456,"publisher":"Leaf publications", "best_sell":true}]} Message size - 190 * 3 = 570 bytes (approx) Useful info - 107 * 3 = 321 bytes (approx) Unnecessary info - 83 * 3 = 249 bytes (approx) Bloated data
31. Disadvantages of REST? • The data being transferred is heavily bloated. • There is no formal contract to communicate.
32. Disadvantages of REST? • The data being transferred is heavily bloated. • There is no formal contract to communicate. • HTTP verbs don’t always describe your API.
33. Disadvantages of REST? • The data being transferred is heavily bloated. • There is no formal contract to communicate. • HTTP verbs don’t always describe your API. • Streaming is difficult.
34. Disadvantages of REST? • The data being transferred is heavily bloated. • There is no formal contract to communicate. • HTTP verbs don’t always describe your API. • Streaming is difficult. • GraphQL problems.
35. What if not REST?
36. gRPC
37. gRPC • gRPC Remote Procedure Call
38. gRPC • gRPC Remote Procedure Call • Open source version of an internal Google product.
39. gRPC • gRPC Remote Procedure Call • Open source version of an internal Google product. • High performance RPC framework.
40. gRPC • gRPC Remote Procedure Call • Open source version of an internal Google product. • High performance RPC framework. • Uses HTTP/2 protocol.
41. gRPC • gRPC Remote Procedure Call • Open source version of an internal Google product. • High performance RPC framework. • Uses HTTP/2 protocol. • Uses Protocol Buffers for message interchange.
42. gRPC • gRPC Remote Procedure Call • Open source version of an internal Google product. • High performance RPC framework. • Uses HTTP/2 protocol. • Uses Protocol Buffers for message interchange. • Can use other formats like JSON, XML.
43. Writing a gRPC service.
44. Writing a gRPC service. (3 step process)
45. Messages and Services Define Writing a gRPC service. (Step 1/3)
46. Messages and Services compiler Define Compile Generated Code Writing a gRPC service. (Step 2/3)
47. Messages and Services compiler Generated Code Servers and Clients Implement Define Writing a gRPC service. (Step 3/3) Compile
48. Let’s make a calculator services
49. Protocol Buffer
50. Protocol Buffer • Interface Definition Language (IDL).
51. Protocol Buffer • Interface Definition Language (IDL). • Message interchange format.
52. Protocol Buffer • Interface Definition Language (IDL). • Message interchange format. • Platform neutral mechanism for serializing structured data.
53. Protocol Buffer • Interface Definition Language (IDL). • Message interchange format. • Platform neutral mechanism for serializing structured data. • Similar to XML or JSON but very small and fast.
54. Protocol Buffer • Interface Definition Language (IDL). • Message interchange format. • Platform neutral mechanism for serializing structured data. • Similar to XML or JSON but very small and fast. 3-10x smaller than XML 10-100X faster than XML
55. Let’s make a calculator services
63. Messages and Services .proto Compiler protoc Generated Code Servers and Clients Define Compile Implement
64. Messages and Services .proto Compiler protoc Define Compile Implement Servers and Clients Generated code C# C++ Dart Go Java Node Objective-C PHP Python Ruby
65. Go Service gRPC server Mobile client Desktop client gRPC Stub gRPC Stub
66. Ruby Service gRPC server Go Service gRPC server gRPC Stub Java Service gRPC Stub Python Service gRPC server gRPC Stub Mobile client Desktop client gRPC Stub gRPC Stub gRPC server
67. Why gRPC? What do I get?
68. Why gRPC? What do I get? • Generated code in 10 languages.
69. Why gRPC? What do I get? • Generated code in 10 languages. • Strict contract between servers and clients.
70. Why gRPC? What do I get? • Generated code in 10 languages. • Strict contract between servers and clients. • Performant and efficient on the wire Small binary messages. Faster serialisation and deserialisation. Multiplexing and Header Compression.
71. • Generated code in 10 languages. • Strict contract between servers and clients. • Performant and efficient on the wire Small binary messages. Faster serialisation and deserialisation. Multiplexing and Header Compression. • In addition to traditional unary APIs you also get Client Streaming APIs Server Streaming APIs Bi-Directional streaming APIs Why gRPC? What do I get?
72. But... What about our existing APIs?
73. But... What about our existing APIs? Do we • Develop both flavors parallelly? • Deprecate existing APIs and ask clients to update their code.
74. grpc-gateway
75. grpc-gateway • A plugin for protoc compiler.
76. grpc-gateway • A plugin for protoc compiler. • An open source tool by grpc-ecosystem.
77. grpc-gateway • A plugin for protoc compiler. • An open source tool by grpc-ecosystem. • Generates a reverse proxy which can communicate to your gRPC server using JSON over HTTP.
79. Using grpc-gateway
80. Using grpc-gateway (3 step process)
81. Using grpc-gateway (Step 1/3) 1. Annotating your proto file.
84. Using grpc-gateway (Step 2/3) 1. Annotating your proto file. 2. Generate reverse proxy and OpenAPI definitions.
85. Annotated Messages and Services .proto Compiler protoc Server interfaces and client stubs
86. Annotated Messages and Services .proto Compiler protoc + grpc-gateway Server interfaces and client stubs Open API specification your-service.json Reverse proxy in Go your-service.pb.gw.go
87. Using grpc-gateway (Step 3/3) 1. Annotating your proto file. 2. Generate reverse proxy and OpenAPI definitions. 3. Write an entry point for the reverse proxy.
89. DEMO
92. Thank you More about gRPC and grpc-gateway • https://grpc.io • https://github.com/grpc • https://github.com/grpc-ecosystem/grpc-gateway • https://grpc-ecosystem.github.io/grpc-gateway