ITT 2017 - Maciek Próchniak - OSGi, Java 9? do we still need modularity in the world of microservices

Maciek Próchniak talks about Microservices. Microservices architecture is one of the most trendy topics in IT these days. Everyone looks at Netflix, LinkedIn or Zalando and tries to be like them.
It’s all very good. But at heart of this revolution lie some well known ideas on modularity and decoupling.
And guess what? Idea of modular Java applications is also not new. Even term “microservice” has been in use on JVM since many, many years. However, the main technology for modular Java - OSGi - was always struggling to gain proper attention and we’re still waiting for modules in JDK itself.
In this talk, Maciek Próchniak explains why you shouldn’t too easily dismiss both OSGi and Java 9 - in many use cases, with little effort they can give you important benefits, without having to spin hundreds of VMs or containers.

Transcript

1. Java 9/OSGi? Microservices?
2. Maciek Próchniak
3. Timeline
4. Meanwhile...
5. FFW 2017
6. Bootiful future?
7. Bootiful future?
8. But...
9. How tall are you?
10. Case 1 - startup
11. Case 2 - frameworks?
12. Case 3 - Enterprise
13. Case 3 - Enterprise
14. What are microservices for?
15. Decoupling
16. Decoupling
17. Coupling • • • •
18. Code level
19. Deployment level
20. Runtime coupling?
21. Stop in between?
22. Stop in between?
23. Stop in between?
24. JVM?
25. Java modules • ◦ ◦ ◦ • ◦ ◦
28. Jigsaw...
32. Leave prejudice … for next 30min
34. Module
35. Module
36. Export/Import module mproch.services.order { requires mproch.services.user; exports pl.mproch.services.order.api; } Export-Package: pl.mproch.services.order.api; uses:="javax.ws.rs,javax.ws.rs.core";version="1.0.0" Import-Package: javax.ws.rs;version="[2.0,3)"
37. What should be module? • • • • •
38. API vs Library vs Service
39. API vs Library vs Service
40. API vs Library vs Service
41. Deployment?
42. Deployment?
43. Versioning?
44. Semantic versioning
46. OSGi? Error executing command: Error restarting bundles: Unable to start bundle 278: Uses constraint violation. Unable to resolve resource demo-persistence-jpa [demo-persistence-jpa [278](R 278.0)] because it is exposed to package 'javax.persistence' from resources javax.persistence [javax.persistence [248](R 248.0)] and org.apache.geronimo.specs.geronimo-jpa_2.0_spec [org.apache.geronimo.specs.geronimo-jpa_2.0_spec [266](R 266.0)] via two dependency chains. Chain 1: demo-persistence-jpa [demo-persistence-jpa [278](R 278.0)] import: (&(osgi.wiring.package=javax.persistence)(version>=2.1.0)) | export: osgi.wiring.package: javax.persistence javax.persistence [javax.persistence [248](R 248.0)] Chain 2: demo-persistence-jpa [demo-persistence-jpa [278](R 278.0)] import: (osgi.wiring.package=org.hibernate.proxy) | export: osgi.wiring.package=org.hibernate.proxy; uses:=javax.persistence com.springsource.org.hibernate [com.springsource.org.hibernate [230](R 230.0)] import: (&(osgi.wiring.package=javax.persistence)(version>=1.0.0)(!(version>=2.0.0))) | export: osgi.wiring.package: javax.persistence org.apache.geronimo.specs.geronimo-jpa_2.0_spec [org.apache.geronimo.specs.geronimo-jpa_2.0_spec [266](R 266.0)] Unresolved requirements: [[demo-persistence-jpa [278](R 278.0)] osgi.wiring.package; (osgi.wiring.package=org.hibernate.proxy)]
47. Java 9?
48. Versioning is HARD...
49. Modules over microservices • • • •
50. Service is not only code
51. Service = Code + Behaviour
52. Behaviour • • •
53. Spring/CDI? @Singleton public class UserService { @Value(“#{user.maxAge}”) private int maxAge; @PostConstruct public void init() { } }
54. Java 9? module UserModule { provides pl.mp.user.api.UserService with pl.mp.user.impl.DbUserService; } module OrderModule { requires UserModule; uses pl.mp.user.api.UserService; } ServiceLoader<UserService> services = ServiceLoader.load(UserService.class); services.iterator()
56. DI - Service Registry (name=”userService”) name=”userService”
57. Context separation @Singleton @OsgiServiceProvider public class UserService { } public class OrderService { @OsgiService @Inject UserService userService }
58. Context separation
59. DOSGi
60. Lifecycle? @Singleton public class UserService { @PostConstruct public void init() { } } @Component public class UserService { @Activated @Updated public void init() { } }
61. Dynamic updates?
62. Thread::kill
63. Services over microservices • • • •
64. But does it have Spring Boot??
65. But does it have Spring Boot??
66. ‘Enterprise’ features • • • • • • •
68. Declarative profiles
69. Profiles deployment
70. DEMO
71. But does it have Spring Boot??
72. OSGi + Karaf platform • • • •
74. Does it work in production?
75. Our case • • • •
76. Our case
77. Do we still need modularity?
78. What do you need?
79. What do you need?
80. What do you need?
82. Thanks