Bundle deployment at state machine level - Ales Justin, JBoss
- 1. Bundle deployment at state machine level Aleš Justin JBoss, a division of Red Hat ales.justin@jboss.org
- 2. 2 • How we started? • Replacement for JMX based Kernel • Dependency State Machine • POJO Component Model • Where are we now? • Aspectized Deployers • Classloader Model • OSGi Integration • VFS • MBeans Support • AOP Integration • Management Model • Spring Integration JBoss Microcontainer
- 3. 3 • Controller • Dependency State Machine • ControllerStates – define your own states • Install context receive callbacks when dependencies satisfied • ControllerContext • Represents a component • Has dependencies • Receives callbacks to implement the model when dependencies are satisifed for a state transition • ControllerMode – automatic, manual, on demand • DependencyInfo and DependencyItem • Define your own dependencies • Write your own dependency item • Standard implementations available
- 4. 4 The basic API public interface Controller { install(ControllerContext c); uninstall(Object name); } public interface ControllerContext { Object getName(); DependencyInfo getDependencyInfo(); void install(ControllerState s); void uninstall(ControllerState s); } public interface DependencyInfo { boolean resolveDependencies(Controller c, ControllerState s); } public interface DependencyItem{ ControllerState getWhenRequired(); boolean isResolved(); }
- 5. 5 • Exisiting implementations • POJO – KernelControllerContext • IOC component model • JMX - ServiceControllerContext • Legacy JBoss service model • Example transitions – implemented by ControllerContexts • Instantiate • POJO – new POJO(); • JMX – registerMBean(); • Configure • POJO – pojo.setProperty(value); • JMX – mbeanServer.setAttribute(objectName, property, value); • Start lifecycle callback • POJO – pojo.start(); • JMX – mbeanServer.invoke(objectName, “start”, null, null);
- 6. 6 • Structural Deployers • VFS usage • Recognise deployment types • User defined – META-INF/jboss-structure.xml • Specification defined – jar, war, ear, etc. • Defines the structure • Where is the metadata? META-INF or WEB-INF, etc. • Where are the classes? / or WEB-INF/classes, etc. • What are the subdeployments? • Aspectized Deployers • Each Deployer does one thing well • Easy to control how much gets done • Off-line tool like the admin console only wants to do parsing • Runtime does everything • Easy to swap out behaviour – e.g. change the classloader Deployer Integration
- 7. 7 • Deployers are Staged • Deployments are processed width first • Aspects • Parsing Deployers • Turns xml into a metadata model attachment • e.g. my-beans.xml -> KernelDeployment • ClassLoading Deployers • Creates classloaders from metadata • e.g. Uses the information from the StructureDeployers • Component Deployers • Splits complicated deployments into units • e.g. KernelDeployment -> BeanMetaDatas • Real Deployers • Does the real work of deployment • e.g. BeanMetaData -> controller.install()
- 8. 8 • Deployment Attachments • Each deployment has attachments • e.g. deployment.getAttachment(KernelDeployment.class) • Two types of attachment • Predetermined – overridden by the user, e.g. Profile service • Transient – parsed by the parsing Deployer • Predetermined overrides transient • Attachments are not used linearly • Example JCA RAR deployment • Parsing done by RAR Deployer – creates RARMetaData • RAR Component Deployer creates ServiceMetaData • No real RAR Deployer, it uses the JMX real Deployer • Alternate Real Deployers Strategy • Doesn't have to use a Microcontainer recognised component model • e.g. Log4j real Deployer could do META-INF/log4j.xml -> log4j config directly
- 9. 9 • Simplifying SPI • Hidden Base • Loader interface • ClassLoaderPolicy • ParentPolicy • Goals • Simple OSGi implementation • Backward compatible • Clean extension Classloader Model Rewrite
- 10. 10 • New ControllerContexts • Introduction of Dependency to Deployers • OSGi Services Support • New Deployers • OSGi Manifest.MF MetaData • DeploymentResolver • OSGi Classloader • Other features • OSGi Core API as Façade • Declarative Services Support • OBR usage OSGi Integration