Нарушение DRY принципа особенно часто возникает в микросервисах. Чтобы избежать этой проблемы, вы можете использовать повторно используемые компоненты, например, приватные пакеты npm. Лучшие практики, которые помогут вам достичь этого включают в себя паттерн ECB для организации кода, манифест 12-ти факторного приложения, использование генерации кода. В нашем проекте мы используем технический стек на основе Node.js, Docker, RabbitMQ, но идеи из этого доклада могут быть использованы для любого технического стека микросервисов

1. Microservice
Architecture with
Reusable Components
Mar 30, 2018

2. Slides JSFest bot

3. Nikita
Galkin
Love and Know:
▰ How to make developers and business happy
▰ Technical and process debt elimination
Believe that:
▰ Any problem must be solved at the right level
▰ Software is easy. People are hard
▰ A problem should be highlighted, an idea should
be "sold", a solution should be demonstrated
Links:
Site GitHub Twitter Facebook
3

4. 4

5. 5
“Wanna do something
good, do it yourself”
Jean-Baptiste
Emanuel Zorg
(Gary Oldman)

7. 7
“Almost all the successful
microservice stories have started
with a monolith that got too big and
was broken up”
from MonolithFirst
Martin Fowler

8. 8

9. 9
“I picked Java because I felt the most
people would be able to understand
the code examples if they were
written in Java. That was the case in
1997, but how about in 2017?
…
But I went for the alternative:
JavaScript.”
27 March 2018

11. Components

12. Best
Practices

13. Reusable Components

14. 14
Why?

15. 15
Don’t
Repeat
Yourself

16. 16
What?

17. 17
Scoped packages

18. Scoped packages
18
▶ npm install @zorg/zf
+ @zorg/zf@1.0.5
added 1 package in 1.727s
▶ cat ~/.npmrc
@zorg:registry=http://npm.zorg-weapon.com

19. 19

20. 20

21. First package
21
▰ @your-scope/code-style
▰ Code Style and Violence
by Anton Nemtsev

22. 22
What is not
reusable
component?

23. 23

24. “Small, autonomous
services that work
together.
24

25. Evolution

26. 26

27. 27
How?

28. 28
Robustness
Engineered for engineers
Useful
Simple
Examples included

29. npm i -g how-to-npm
how-to-npm
Or
Free 1,5 hour-long video:
How to Write an Open
Source JavaScript Library

30. Git flow
30How to convince the team?

31. 31
How to convince the manager?

32. “Wanna do
something good,
do it yourself”
Zorg

33. “Wanna do
something good,
do it yourself”
Zorg

34. “Don't use require(../../utils/logger),
use npm packages” © Galkin
Awesome Pair!
But how reuse code...
Microservices

35. 35
How to develop
reusable
components?

36. ▰ npx scripts
▻ eslint helper
▰ plop
▰ yeoman.io
▰ raml2html
Code, spec, docs generators
36

37. Generators
37

38. Test Driven Development
38
FAIL
PASS
TDD
REFACTORING
“Repetition of a very short
development cycle: requirements are
turned into very specific test cases,
then the software is improved to pass
the new tests, only.”
Kent Beck

39. Types or Documentation Driven Development
39
tsc
Add JSDoc
TDD
▰ choose typescript or JSDoc
▰ autocomplete for engineers
▰ always actual code documentation
▰ puppeteer source-code is
awesome JSDoc example
REFACTORING

40. /**
* @typedef {Object} CoverageEntry
* @property {string} url
* @property {string} text
* @property {!Array<!{start: number,
end: number}>} ranges
*/

41. Theft Driven Development
41
STEAL
ADOPT
TDD
SHARE

42. Reusable Components

43. I'll show you my
package.json
during speaker
corner

44. 44
Where?

45. Source code
storage
CI for
build and test
Artifact
storage

46. Git flow
46
Gitflow

47. Git flow
47
Gitflow

48. Github Flow

49. Monorepo with Lerna

50. Or one repo for one component?

51. Your DevOps Engineer: @#_$!

52. Your DevOps Engineer: @#_$!

53. 12factor.net

54. “II. Dependencies
Explicitly declare and
isolate dependencies
54

55. “III. Config
Store config in the
environment
55

56. “V. Build, release, run
Strictly separate build and
run stages
56

58. “VI. Processes
Execute the app as one or
more stateless processes
58

59. “XI. Logs
Treat logs as event
streams
59

60. stdout stderr

61. 61
How to develop
microservices?

62. MonolithFirst

63. How your system works?

64. ECB is a variant of Model/View/Controller (MVC). It
was published by Ivar Jacobson (Ericsson Co.) in
the 80's with a focus on separating responsibilities
of elements in Object Oriented Systems.

65. Boundary – objects that interface with system
actors (e.g. a user or external service). Side
effected.
Boundary component should be reusable.
EBC Pattern – Boundary
65

66. Boundary place for validation

67. ▰ Wrapper for Enterprise Bus
▰ File Storage wrapper
(S3/Local FileSystem)
▰ JSON RPC with different
transports
Possible Boundaries Components
67

68. Control – objects that implement business
logic. This code has the main value for
business.
This part of every microservice is unique.
EBC Pattern – Control
68

69. Control – just control.

70. Entity – objects representing system data,
often from the domain model. In our
application we use an entity also for
transforming data from one format to another.
For example, from XML to JSON.
Entity can be shared between applications as
interfaces or components.
EBC Pattern – Entity
70

71. Entity for data transform

72. microservices base application with:
▰ Base boundary class
▰ App class with start stop
▰ Default logger
▰ Hooks
Basement
72

73. 1. Only Boundary provide services for the
"other world".
2. Boundary can call only to Control.
3. Control can call anybody.
4. Entity can't call anybody (!), only be called.
EBC Pattern
73

74. 74
Why does it matter?

75. Bootstrapping and Graceful
shutdown

76. Interface Microservice {
void start();
void stop();
}
Microservice interface
76

77. Bootstrapping

78. 1. Attach uncaught exception hooks.
2. Log start of bootstrapping.
3. Verify configuration.
4. Init boundaries and controls.
5. Attach shutdown hooks.
6. Log finish of bootstrapping.
Bootstrapping
78

79. Graceful Shutdown

80. For graceful shutdown application should:
1. Log start of graceful shutdown.
2. Close incoming boundaries. For example,
stop accepting new tasks for processing
from queue, stop handling new incoming
http requests, etc.
Graceful shutdown
80

81. 3. Set a forced timeout for completion current
tasks or save them for future processing.
Recommended value for this timeout is not
more then 5 second.
4. Notify consumers about shutdown. For
example, send heartbeat-shutdown.
Graceful shutdown
81

82. 5. Correctly disconnect from all connections.
For example, database, RabbitMQ, Redis,
etc.
6. Log finish of graceful shutdown and stop
the process.
Graceful shutdown
82

83. 83Let’s summarize!

84. ▰ Reusable Components
▰ Monolith First
▰ The Twelve Factors
▰ EСB (Entity, Boundary, Control) Pattern
▰ Bootstrapping and Graceful shutdown
Microservice Best Practises
84

85. 85
Robustness
Engineered for engineers
Useful
Simple
Examples included

89. 89
Thank you for attention!
Be consistent in your
microservices!!!
You can find me on Twitter as @galk_in
Slides are available at speakerdeck.com/galkin
or on my site galk.in

90. Slides JSFest bot

91. ▰ koa
▰ bunyan
▰ dotenv-safe
▰ gatsbyjs
▰ rxjs
My favorite packages
91
▰ pre-commit
▰ eslint
▰ jest
▰ raml-cli
▰ dredd