This document discusses using Rails as a backend for front (BFF) layer in a microservices architecture. It describes how Rails was used to build the BFF layer for an e-commerce site called HPB, acting as an API gateway between the client and various backend services. Key points discussed include using Puma to improve throughput, caching APIs to reduce response time, and implementing an API gateway to further optimize network performance between the BFF and backend services.

1. Rails BFF
Microservices Meetup vol.5 (API Gateway & BFF)
shotat @Recruit Lifestyle

2. • @shotat (GitHub, Twitter)
• 2015.04 ~ 2015.12
SIer
• 2016.01 ~ Now
• Ruby, Elixir, Vim, Docker

3. Case Study:
BFF

4. Agenda
• HPB
•
• API
• Rails & Spring
• BFF Rails
•

5. Agenda
• HPB ◁
•
• API
• Rails & Spring
• BFF Rails
•

7. •
• 2007
• ※ HPB

8. HPB
10
=> &
=> 😥

9. •
-
-
•
-
-

11. MicroServices ?

12. Monolithic App HPB
Client
(web)
Monolith

13. MicroServices & BFF
Client
(web)
BFF Services

14. BFF(API Gateway) API
Client
(web)
BFF Services

15. Services
Client
(web)
BFF Services

16. Client
(web)
BFF Services

17. HPB MicroServices
• View/Logic
• Service
•

18. MicroServices
😢

19. Agenda
• HPB
• ◁
• Rails & Spring
• API
• BFF Rails
•

20.
BFF / API Server

21. MicroServices & BFF
Client
(web)
BFF Services

22. BFF & API (services)
Client
(web)
BFF API Server

23. BFF & API (services)
Client
(web)
BFF API Server

24. BFF / API

25. BFF / API Server
Client
(web)
BFF API Server
New App
Old App

26. Strangler Application
Router(Proxy)

27. BFF / API Server
Client
(web)
BFF API Server
New App
Old App

28. New App
BFF API Server
Client
(web)
scope
Old App

29. Agenda
• HPB
•
• API ◁
• Rails & Spring
• BFF Rails
•

30. API
• REST
(BFF or API Gateway API
)
• API
• => REST

31. Lorem ipsum dolor sit amet
Lorem ipsum
Lorem ipsum
Lorem ipsum
Lorem ipsum dolor sit amet, consectetur
Lorem ipsum
Lorem
Ipsum
Lorem
HPB
•

32. Lorem ipsum dolor sit amet
Lorem ipsum
Lorem ipsum
Lorem ipsum
Lorem ipsum dolor sit amet, consectetur
Lorem ipsum
Lorem
Ipsum
Lorem
HPB
• UI
( )
•
•
+
+

33. Lorem ipsum dolor sit amet
Lorem ipsum
Lorem ipsum
Lorem ipsum
Lorem ipsum dolor sit amet, consectetur
Lorem ipsum
Lorem
Ipsum
Lorem
HPB
• BFF call API
7
- x 5
-
-
• API
- parameter
- View
+
+

34. Agenda
• HPB
•
• API
• Rails & Spring ◁
• BFF Rails
•

35. API Server: Spring Boot
• Java
•
•
• Doc Swagger

36. BFF Layer: Ruby on Rails
•
•
• Rails

37. BFF Rails
•
•
•
➜ Node.js, Golang
🤔

38. • : BFF / API Server
• :
• : SPA
➜ Ruby Rails

39. Agenda
• HPB
•
• API
• Rails & Spring
• BFF Rails ◁
•

40. BFF layer
• Web API Gateway
iOS, Android BFF
• API ( + caching)
• session
• (SS) rendering

41. Rails

42. Model
ControllerView
USER
DB
Ruby on Rails
ActiveRecord Pattern

43. Model
ControllerView
USER
DB
Ruby on Rails
ActiveRecord Pattern

44. Model
ControllerView
USER
DB
BFF API
ActiveRecord Pattern
×
API

45. Rails BFF
• Active Record DB
• Rails

47. Model
ControllerView
USER
DB
Ruby on Rails
ActiveRecord Pattern

48. BACKEND
Model
Repository
API
Data Accessor
API Aggregator
ControllerView
USER
BFF

49. BACKEND
Model
Repository
API
Data Accessor
API Aggregator
ControllerView
USER
BFF

50. MVC + R
• One Repository : One Endpoint
• Model Aggregator
• : Controller Rails
• :

51. Rails

52. BFF 🤔
• API
• API
Invalidation

53. • API
=>
Blocking IO
• API
=>

54. • API
=>
Blocking IO
• API
=>
➜

55. Performance
API call
throughput: 30 rps/host
response time: 120 ms
※ Spec
CPU: 2 Cores, 3.20GHz, Intel(R) Xeon(R) CPU E5-2667 v4
Memory: 8GB

56. Response Time 120 ms
• Rails : 40ms
• NW : 10ms
• API
IO 70ms

57. Performance
• API
• NW
•

58. Performance
• API
• NW
•
➜ …?

59. • 120ms
• throughput

60. • 120ms
• throughput
➜

61. …

62. BFF

63. • Throughput
• ResponseTime

64. Throughput

65. Throughput :
Rack Puma

66. What’s Puma?
• Puma: Thread Rack
• IO wait Thread
=> IO wait BFF
• HPB Unicorn

67. Puma
• Request thread
CPU throughput
• API
1

68. Throughput :
BFF

69. BFF
• CPU BFF
= Ruby(Rails)
• View
• BFF
API

70. ResponseTime

71. ResponseTime :

72. API request
• IO wait
API
• Faraday + Typhoeus gem
• :
debug

73. ResponseTime :
API caching

74. API cache
• API
• :
caching invalidation

75. ResponseTime :
API Gateway

76. API Gateway
• BFF batch API Gateway
• App
• : mercari/widebullet
JSON-RPC batch request-> HTTP requests
• :

77. API Gateway
BFF API Server
API Gateway
e.g. Widebullet

78. API Gateway
BFF API Server
API Gateway
e.g. Widebullet

79. API Gateway
BFF API Server
API Gateway
e.g. Widebullet

80. NW IO wait
120ms 75ms

81. BFF

82. • Throughput
=> BFF
• ResponseTime
=> API
API Gateway

83. Agenda
• HPB
•
• API
• Rails & Spring
• BFF Rails
• ◁

84. BFF Rails: pros/cons
naive