Java Data Intensive Serving Container - JDisc
Vespa's Java container - JDisc, hosts all application components as well as the stateless logic of Vespa itself. Which particular components are hosted by a container cluster is configured in services.xml. The main features of JDIsc are:
- HTTP serving out of the box from an embedded Jetty server, and support for plugging in other transport mechanisms.
- Integration with the config system of Vespa which allows components to receive up to date config (by constructor injection) resulting from application deployment.
- Dependency injection based on Guice (Felix), but extended for configs and component collections.
- A component model based on OSGi which allows component to be (re)deployed to running servers, and to control which API's they expose to others.
- The features above combine to allow application package changes (changes to components, configuration or data) to be applied by Vespa without disrupting request serving nor requiring restarts.
- Standard component types exists for
- A general chain composition mechanism for components.
- Implement "Hello, World!" using the Vespa Applications tutorial
- Building an HTTP API using request handlers and processors.
The JDisc container provides a framework for processing requests and responses,
named Processing - its building blocks are:
- Chains of other components that are to be executed serially, with each providing some service or transform
- Processors that change the request and / or the response. They may also make multiple forward requests, in series or parallel, or manufacture the response content themselves
- Renderers that are used to serialize a Processor's response before returning it to a client
Application Lifecycle and unit testing:
- Configuring components with custom configuration
- Component injection allows components to access other application components
- Learn how to build OSGi bundles and how to troubleshoot classloading issues
- XML processing with JAXB and JAXP (DOM, SAX, StAX)
- Using Libraries for Pluggable Frameworks from a component may result in class loading issues that require extra setup in the application
- Unit testing configurable components
- Handlers and filters:
- Searchers and Document Processors:
Other related documents
- Versioning Components
are capable of connecting to and forwarding requests to a
remote server on a specific protocol, e.g. the
HttpClientis a client provider for HTTP and HTTPS
- To accept incoming connection on other protocols than HTTP/HTTPS, develop custom server providers starting with the tutorial
- The Chain Builder API
- Designing RESTful web services as Vespa Components
- healthchecks - using the Container with a VIP
- Vespa Component types: The Container's request processing lifecycle