I guess the ral problem, is that we have two competing goals:
1) Custom Server Assemblies via car-maven-plugin - To provide multiple
levels of modules/plugins to allow users to choose the level of
components hey need, like Jetty6 vs. Jetty7. This is sort of what
ServiceMix allows, by starting with the SMX4 Kernel and adding which
features or individual OSGi plugins you want. It would be a great goal
to finally implement in Geronimo 3.0, so users could choose between JEE5
and JEE6 components.
2) Preserving application compatibility on newer servers - If a user has
an app working on Geronimo 2.0.x or 2.1.x, then we shouldn't require
them to modify the app (source or plans) for it to work on future releases.
Scenario #2 is the one I'm trying to preserve, as users expect this of us.
-Donald
David Jencks wrote:
Both Donald and I seem to feel the answer to this is obvious but we have
diametrically opposed points of view so maybe its time for discussion.
After endless discussion we answered a related question for our specs
with the following principal:
The artifactId will contain the version number of the spec
The version will only contain the geronimo version.
I'm happy with this decision for specs.
We include a lot of other projects in geronimo, such as activemq, axis,
cxf, jetty, tomcat, etc etc. These projects evolve over the years and
when they get to a fairly incompatible change level they generally
change the major version number, such as jetty 6 to jetty 7, activemq 4
to activemq 5, etc etc.
1. Do we want to give our users a clue about which version of the
external project they are using? If so, it has to be in the maven id
for our plugin that, through dependencies, installs the external project.
2. If so, how? We get groupId, artifactId, version. I don't see a
plausible way to use the groupId, leaving us with artifactId and version.
2.a. If so, how much detail? E.g. do we want to tell users they are
getting some flavor of jetty 6 or do we want to tell them they are
getting jetty 6.1.14?
2.b should the version numbering relate to the external project
integration or to the geronimo version it fits with?
My answers to these questions:
(1) definitely YES. We may want to offer support for more than one
level of the external project, and I don't think concealing major
changes in an external code base is a good idea.
(2)
- Putting the first digit of the external version in the artifact Id
clearly indicates the general level of external project support while
allowing easy upgrades to later external versions within that major
version. These are likely to be fairly compatible so may work find with
artifact-aliases support rather than recompiling. This also clearly
separates the geronimo portion of the version from the external project
version since the external project version is not part of the maven
version.
- Changing major version of an external project may well require
changes in code that uses the project. It's almost certain to require
repackaging of plugins that run against the project; e.g. the jetty
gbean wrappers changed dramatically from jetty 5 to 6 and are changing
again from 6 to 7.
- using the external project version would result in something like a
version of 5.2.2.2-SNAPSHOT for our current amq 5 integration. However,
there are some bugs so we'll need amq 5.3 or at least 5.2.1 before we
release. So we'll need 5.3.2.2-SNAPSHOT even though our integration
code didn't change. I guess we could use 5.2.2-SNAPSHOT although this
seems very confusing compared to the amq version.
So I'm having a lot of trouble seeing how any scheme other than stuff
like activemq5 for the artifactId is remotely plausible.
Thoughts?
david jencks
