AS7: Re-thinking WS container integration
by Alessio Soldano
JBossWS 4 is going to be the jbossws integration layer for JBoss AS 7.
This is both a chance of working on major spi changes / cleanup [1] as
well as revisiting the whole way the installed ws stack (CXF or Native)
is used for deploying endpoints.
*DOMAIN MODEL*
One of the idea AS7 comes with is exposing a domain for centralized
control of the application server(s). JBossWS is going to contribute a
ws subsystem to that domain, at least for setting the server level
configuration aspects of the webservice engine.
The most obvious element being included in ws subsystem of the AS7
domain are the information required for setting the "WS config", i.e.
what we currently have in the WSServerConfig bean declared in
stack-agnostic-jboss-beans.xml (webServiceHost, modifySoapAddress, etc.).
We'll then have the records' management configuration, which is also
something configured at server level (WSMemoryBufferRecorder,
WSLogRecorder, etc. currently in stack-specific-jboss-beans.xml).
Besides the easy things above, we should probably allow for
pre-configuring a given application server instance with default
endpoints (perhaps clients too in the future), meaning users can specify
an endpoint configuration and have that endpoint included as part of the
application server, the same way they would have had if they deployed an
archive with the corresponding endpoint declaration [2].
*API REVIEW*
In the process of revisiting the JBossWS SPI, we need to properly split
the current jbossws-spi project contents into:
- a set of classes/interfaces required for proper abstraction of jbossws
components (pretty much what we have today, 2 stacks, perhaps multiple
supported target container[3], ...) and to have a defined interface
towards other related jboss projects (EJB3 for instance)
- a public API meant for actual user consumption, which would end up in
a AS7 module visible to user deployments
The latter is going to include the classes/interfaces the domain model
maps to (ws config, records stuff, service/endpoint/deployment basic
stuff like endpoint class, publish address, ...) and what's required for
tooling (wsconsume / wsprovide Ant tasks, command classes, etc.)
*CONTAINER INTEGRATION*
For integrating into AS7, we need to rethink the way jbossws handles
deployments in terms of services (which are one of the key elements of
AS7). At the end of the day, what the ws subsystem is supposed to do is
providing facilities for starting/stopping webservice endpoints (and
clients). Given the management requests of AS7, the domain model, etc.
it's time to think about that as something not directly tied to the
deployment process only, but generally available as a service instead.
Other services in the application server might depend on or simply make
use of this service [2]. The deployers (DeploymentUnitProcessors in AS7)
should just be "clients" of this service.
To a certaint extent this way of thinking about the container
integration fits with what has been done in JAXWS 2.2 Endpoint API and
-for instance- the way an Apache CXF endpoint is started. We should be
able to parse and digest an endpoint configuration, properly setup the
transport layer and then simply trigger the endpoint deployment.
Currently (AS 5/6) the ws deployment goes through many ws deployers,
most of which wrap jbossws "deployment aspects" (DA). Those can probably
be splitted into few groups:
1) DAs dealing with figuring out / processing basic and container
related informations (context root, url pattern, endpoint address,
endpoint name)
2) DAs converting information coming from merged metadata (descriptors +
annotations) into the jbossws-spi metadata
3) DAs dealing with the transport (creating / modifying the jbossweb
metadata for ws endpoints)
4) DAs dealing with ws stack internals (for native: UMDM creating,
eventing, rm, eager init, ... for cxf: jbossws-cxf descriptor creation,
bus creation, ...)
Some of these are most probably meant for remaining part of the
deployers (probably 1,2,3), the rest (probably 4) is actually going to
become part of the services providing facilities for starting/stopping
an endpoint.
The jbossws-spi should be seen as the interface for feeding the ws
services that deal with endpoints.
AS7int.gif
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While the AS7 / domain management system is going to simply make use of
the public api part of jbossws-spi, the deployers are probably going to
process all the metadata information coming from annotations and
deployment descriptors into the jbossws-spi metadata and then feed the
endpoint creation service. Deployers will also deal with / set required
dependencies on other services involved in the deployment phase, for
instance the web server service (which for instance will be required to
properly create a context for the endpoint(s)).
*WS SERVICES*
What is then required to be a (WS) service? Apart from some obvious
facilities like the endpoint registry and a server configuration
provider service, the main service is the one meant for
starting/stopping endpoints.
We need to carefully define a stable interface for this service, so that
it can be maintained without much changes in the future. This mainly
implies establishing the inputs for creating/starting an endpoint,
basically the metadata carrying the required information for that.
Ideally that should already be covered by what we have in jbossws-spi,
plus stack specific configuration stuff.
For CXF that's everything that can be included in the jbossws-cxf.xml /
cxf.xml, for Native it's what comes from the union of the info in
endpoint configurations (configName / configFile...) and other
additional optional descriptors (e.g. the jboss-wsse-*.xml).
For the sake of practically supporting future extensions / changes, the
stuff above should most probably be modelled as AS7 extensions, each
coming with its own parser bound to a given xsd namespace. For
supporting advanced usecases (iow WS-*), the domain model should
probably simply accept a pointer to additional xml configuration (beyond
what's in the basic user API which is part of jbossws-spi, etc. - see
above). Depending on the default namespace of the provided xml, the
proper parser (coming from the installed ws stack) would be used and the
domain enriched with the provided information for creating endpoint(s).
At the end of the day, most (if not all) the information is the Bus (for
jbossws-cxf) / the UMDM (for jbossws-native).
What do you think about this all? My plan would be to get to an
agreement on the main design for JBossWS 4 / AS 7 integration, perhaps
by some iteration here. Then we can isolate/create/update jiras for what
needs to be done and start scheduling things.
[1] JBWS-2709, JBWS-3115, JBWS-3105, JBWS-2338
[2] http://community.jboss.org/message/571376#571376
[3] JBossWS 4 will most probably at first support AS 7.x only
--
Alessio Soldano
Web Service Lead, JBoss
13 years, 5 months
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