This document discusses managing client-server compatibility when deploying updates to an enterprise client. The client queries the server at login to determine the version of shared bundles. It then queries a central repository for any compatible updates. If an update is available that does not require an intervening server upgrade, the client can install the update. Otherwise, the update is ignored and the user is notified that they must first upgrade the server. This approach allows each customer's server to be updated independently while maintaining compatibility between the client and server from a single codebase.

1. Managing enterprise client
deployment with p2
Thomas Kratz
12.11.2010
thomas.kratz@eiswind.de

2. About me
Born 1970,
Started on a ZX81 in the early 80‘s
Doing a daytime job with JSF Frontend
(leave that uncommented)
Developing a commercial book publisher‘s software
with my own company Eiswind Software on
OSGi, Spring, Hibernate, Eclipse RCP since 2007
Casual Eclipse and Apache project contributor
(could you provide a patch ?)
Sometimes dreaming in code.

3. The scenario
• RCP Client talks to backend over HttpInvoker
• Server talks to client through XMPP
Synchronous
Remote procedure calls
Asynchronous messaging
(XMPP)

4. Client-Server compatibility
• Client and Server share domain classes and
service interfaces
Client bundles
Server bundles
Shared bundles must be
„wire compatible“

5. Definition of „wire compatible“
• OSGi versioning gives us
– major, minor, micro
– qualifier
• We defined that „wire compatible“ means
major,minor and micro must match.
• Qualifier my change, shared bundles must be
API compatible
Manifest-Version: 1.0
Bundle-ManifestVersion: 2
Bundle-Name: Domain Plugin
Bundle-SymbolicName: de.eiswind.mango.domain
Bundle-Version: 1.7.0.20101020

6. Uhh, we have customers
• We are not multi-tenant, so each customer
has his own server instance.
• Updating the server at customer site happens
at different times
• Client and server should update from single
central repository

7. Managing the client
• At login time the client first queries
the server for his OSGi version of the
shared bundles
• Then he looks in the repo for
updates that match the servers
version in terms of „wire
compatible“

8. Managing the client (2)
• If, at login time, server and client
version do not match, Workbench
starts up for getting the update
with user interface disabled.
• If an update is available, but would
need server upgrade first, it is
ignored.

9. The solution: p2 queries
• We know the servers shared Bundle version,
so we do a query for compatible updates of
the product Installable Unit:
IQueryable<IInstallableUnit> queryable =
provisioningContext.getMetadata(new NullProgressMonitor());
IQueryResult<IInstallableUnit> matches =
queryable.query(
QueryUtil.createIUQuery("de.eiswind.mango.client.core.mango",
new VersionRange(Version.createOSGi(major, minor, micro), true,
Version.createOSGi(major, minor, micro + 1), false)),
new NullProgressMonitor());

10. Building the Update
• The QueryResult gives us all compatible IU‘s
from the repository. We pick the latest and
construct an update:
IQueryResult<IInstallableUnit> allIUFromRepo =
getAllInstallableUnitFromRepository(provisioningContext);
List<IInstallableUnit> units = new ArrayList<IInstallableUnit>();
for (Iterator<IInstallableUnit> it = allIUFromRepo.iterator(); it.hasNext();) {
newIUFromRepo = it.next();
units.add(newIUFromRepo);
}
// check if something is available at all omitted here
Collections.sort(units);
// get the latest matching update
newIUFromRepo = units.get(units.size() - 1);

11. The UpdateOperation
// now we must ensure that we don‘t get updates we
// do not want
Update update = new Update(oldIUFromProfile, newIUFromRepo);
ProvisioningSession session = new ProvisioningSession(agent);
final UpdateOperation operation = new UpdateOperation(session);
status = operation.resolveModal(sub.newChild(100));
// check status omitted here
operation.setSelectedUpdates(new Update[0]);
for (Update available : operation.getPossibleUpdates()) {
if (available.equals(update)) {
log(IStatus.INFO, "Update matches available: " + update, null);
selected[0] = available;
operation.setSelectedUpdates(selected);
}
// now run the ProvisioningJob

12. Coming up: The server
• Currently server is beeing ported to the virgo
runtime
• Virgo doesn‘t work with p2 yet, but knows the
concept of a „remote repository“

13. Server updates
P2 and virgo repo on eiswind.de
Server at Customer BServer at Customer A
Pick up virgo
repository updates

14. The update cycle
Server at Customer A
P2 and virgo repo on eiswind.de
1)
2) Client recognizes server update
3) Client pulls update from p2 repo

15. Thanks for listening
• If you‘d like to see the full update code
example, just ask.
• You can reach me on
• thomas.kratz@eiswind.de
• http://www.eiswind.de