OSGi Community Event 2016 Presentation by Balázs Zsoldos (Everit Kft.) Have you ever felt that your system could collapse like the house of cards? Has it ever happened to you that an OSGi component got unsatisfied and that caused a chain reaction? It can be hard to find the root cause when you see 50+ non-active components. In this talk, we will show, how these issues can be solved quickly so programming can be fun again. In the first part of the talk we will introduce our component model that is based on the concept of Declarative Services. There are minor changes, the ones that allow us to handle large set of component graphs easily. In the second part we will play a short game with the audience. One must cause a mistake in a large system while another developer (who did not see the change) must fix it. there will be a demo where we set up a complex Servlet Container with multiple Servlet Contexts, Servlets, and Filters via configuration.

1. Avoid the chaos
Handling 100+ OSGi components
Balázs Zsoldos

2. Everit Component Model (ECM)
since 2014

4. Source: Inglourious Basterds

5. Why another Component Model?

6. Blueprint
Declarative Services

7. OSGi Service
Component
Reference

8. DS
DataSource
Business
Log C
Cache
Declarative Services

9. UserDataServlet
Servlet
Context
ErrorServletLoginServlet
Not Supported
Declarative Services

10. UserDataServlet
Whiteboard
extender
ErrorServletLoginServlet
Whiteboard
Declarative Services

12. Whiteboard
extender

13. Whiteboard
extender
Aries JPA
Extender
Blueprint

14. Source: Reservoir dogs movie

15. Whiteboard extender ServletContextComponent
Authentication Filter
URL Redirect Filter
User Mgmt Servlet
Login Servlet
Authentication Filter
URL Redirect Filter
User Mgmt Servlet
Login Servlet
TestComponent

16. Source: Home Alone movie

17. Declarative Services
Everit Component Model

18. UserDataServlet
Servlet
Context
ErrorServletLoginServlet
Not Supported
Declarative Services

19. Package 2
Bundle B
Bundle A
Package 1 Capability
Bundle BBundle B

20. UserDataServlet
Servlet
Context
ErrorServletLoginServlet

21. AuthFilter
Servlet
Context
Whatever
Filter
URLRewriteFilter

22. AuthFilter
Servlet
Context
Whatever
Filter
URLRewriteFilter
0. 1. 2.

23. XML Transform
Camel
Route
XML
Digital Signature
XML Validator
0. 1. 2.

25. Authentication
Servlet
Servlet
Context
Authorization
Servlet
LoginServlet
/login /auth /auth
/a /authrConfigAdmin /authn

26. logService.target: (implementation=felix)
servlet.clause: loginServlet;filter:=(service.pid=...)
servlet.clause: ...;init_param1=value1;init_param2=value2
Targeting references

29. public enum ComponentState {
STOPPED,
UNSATISFIED,
STARTING,
ACTIVE,
STOPPING,
FAILED,
FAILED_PERMANENT
}
// Throwable, restart on configuration change
// Throwable, never restart

30. ecm-extender-ri
ecm-component-ri
ecm-component-api
ecm-metadata
ecm-util-method
linkage-api
capabilitycollector
ecm-annotation-metadatabuilder
ecm-annotation
ecm-extender-api

31. @StringAttribute
private String stringAttribute;
public void setStringAttribute(String stringAttribute) {
this.stringAttribute = stringAttribute;
}
private Integer integerAttribute;
@IntegerAttribute
public void setIntAttribute(Integer integerAttribute) {
this.integerAttribute = integerAttribute;
}
private String[] names;
@StringAttribute(dynamic = true)
public void setStringAttribute(String[] names) {
this.names = names;
}

32. OSGi
service Bundle Capability
ECM Component

33. Demo

34. http://everit.org/ecm/index.html

36. Source: Inglourious Basterds

37. Source: Inglourious Basterds

38. ecm-extender-ri
ecm-component-ri
ecm-component-api
ecm-metadata
ecm-util-method
linkage-api
capabilitycollector
ecm-annotation-metadatabuilder
ecm-annotation
ecm-extender-api
OSGi
service Bundle Capability
ECM Component
Twitter: @EveritOrg