moduarlity patterns with osgi
TRANSCRIPT
Modularity
patterns
with OSGi
Paul Bakker@pbakker
Agenda µServices architecture Whiteboard pattern Reusable and configurable services Extender pattern Real world example
Modules
https://www.flickr.com/photos/128326674@N06/
http://www.carpartsireland.ie/uploads/Reardriftspoiler144cm003.jpg
Service contract
Module
Implementation classes
Hide implementation
details
Make imports and
exports explicit
Export only public interfaces
Import public interfaces
provided by others Export-Package: example.api;version=“1.0.0"
Import-Package: some.otherapi;version=“[1.0,2)"
ServiceRegistry
Bundle registering a service
Bundle using a service
PublishMyInterface
LookupMyInterface
OSGi Service Registry
Demo
Components only communicate using service APIs
Implementation should be replaceable!
A simple example
ResultsREST
ResultsStorage
StatsAggregator
StatsREST
TracksREST
TracksStorage
Services may use multiple other services
Demo
Always be prepared for dynamics
Services must
contain their own data
ResultsStorage
TracksStorage
ResultsStorage
TracksStorage
Examples
MongoDB Each service owns a
collection
Relational
Each service owns a
set of tables
ResultsStorage
TracksStorage
...
...
Table A
...
...
Table B
...
...
Table C......
Table D
...
...
Table F
...
...
Table E
...
...
Table G
Whiteboard
Pattern
PluginRegistry
Plugin Plugin Plugin
Whiteboard
Use multiple services with the same interface
Demo
Real life examples
Amdatu REST Apache Felix HTTP Whiteboard Amdatu Scheduling Amdatu Bootstrap plugins Apache Felix Gogo commands
Configuration
What if
all services
do the same thing
with different config?
ManagedServiceFactory
Config
Config
Config
Component
Component
Component
Managed Service Factory
Extender Pattern
Real life examples
Providing static web resources Amdatu JPA (weaving) Templates in Amdatu Bootstrap
What if
my bundles don’t
really “do” anything?
Resourcebundle A
Resourcebundle B
Extender
Component
Component
Component
Extender pattern
Demo
Do NOT overuse
Adding extenders is like adding a DSL: Powerful and confusing.
BootstrapCore
AmdatuPlugin
Dependency Manager
Plugin
ProjectPlugin
WorkspacePlugin
BaseliningPlugin
BootstrapWeb backend
BootstrapShell
TemplateExtender
Projecttemplates
Workspacetemplates
BootstrapWeb UI
bnd
Plugin Whiteboard
...Plugin
Real world
example
Bootstrap
A modular architecture gives us:
Maintainability
Extensibility
Freedom to change
Wrap up
But what if I want
Spring
EJB
…?
Just don’t… You really don’t need to.
Eclipse OSGi plugin http://bndtools.org/
That’s us http://luminis-technologies.com
Open source OSGi components
http://www.amdatu.org/
Amdatu
Paul Bakker [email protected] @pbakker