Mikroserwisy nadal są jednym z bardziej modnych tematów w IT. Każdy patrzy na Netflixa, LinkedIna, Zalando (albo Allegro...) i chce być taki jak oni. No i wszystko bardzo ładnie. Ale w samym sercu tej rewolucji są dobrze znane idee modularyzacji i decouplingu. I co? Okazuje się że pomysł modularyzacji Javy także nie jest nowy. Nawet słowo "mikroserwis" jest w użyciu na JVM od ponad 10 lat. Niestety, główna OSGi czyli główny sposób modularyzacji Javy nadal walczy o popularność, a w samej Javie nadal czekamy na moduły.... W ramach prezentacji chciałbym opowiedzieć (i pokazać w czasie krótkiego demo) czemu nie należy tak od razu odrzucać OSGi czy Javy 9, w wielu przypadkach możemy osiągnąć wiele ciekawych korzyści bez konieczności uruchamiania setek kontenerów.

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
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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
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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?
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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
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50. Service is not only code

51. Service = Code + Behaviour

52. Behaviour
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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
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64. But does it have Spring
Boot??

65. But does it have Spring Boot??

66. ‘Enterprise’ features
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68. Declarative profiles

69. Profiles deployment

70. DEMO

71. But does it have Spring Boot??

72. OSGi + Karaf platform
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74. Does it work in
production?

75. Our case
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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