Thanks Stephan for valuable comment. I agree that it'd be possible to simply remove all Import-Package headers from all bundles. But that's not done by default. You have to be very explicit when creating custom distribution. I'm not doing this change upstream and also I created this https://issues.apache.org/jira/browse/KARAF-6200 as "proposal" with minor priority.
Using fragment bundle sounds like great alternative - was it the same case with org.apache.aries.blueprint.core.compatibility-1.0.0.jar ? regards Grzegorz Grzybek wt., 19 mar 2019 o 11:30 Siano, Stephan <stephan.si...@sap.com> napisał(a): > Hi Jean-Baptiste, > > What Grzegorz is proposing looks to me like some magic behind-the-scenes > automatic wrap for all kind of installed bundles. > > I am not sure if this is really such a good idea. If it works, it can make > things work that do not work without some significant effort like manually > wrapping all bundles that reference the servlet API. If there are issues, > you will have a situation, which is extremely hard to analyze with having > bundles wiring to other bundles they are not supposed to be wiring > according to their manifest. > > Even if that works with servlet API 4.0 for some reason, once that > mechanism is there, it will likely be used for other packages, and once you > have defined changes to several packages which cause the auto-wrap of > dozens of bundles, I really think that it will be very difficult to > understand the wiring afterwards. > > Therefore IMHO the least ugly workaround for this issue would be to create > a fragment bundle for the servlet-api bundle that exports the packages with > some lower version number (e.g. 3.2) that is only installed if it's really > necessary. Over time the developers of the bundles referencing the servlet > API hopefully asses whether their bundle also works with the servlet 4.0 > API and adapt their import ranges accordingly (so the fragment can go away > eventually). > > Best regards > Stephan > > -----Original Message----- > From: Jean-Baptiste Onofré <j...@nanthrax.net> > Sent: Dienstag, 19. März 2019 10:24 > To: dev@karaf.apache.org > Subject: Re: Idea - how to override bundle headers without wrap: > > Hi Grzegorz > > I think what you are proposing is at different level than wrap. > > wrap is more for single jar (and works "outside" of Karaf) whereas your > proposal is at feature level. > > It makes sense but we have to keep it simple and clear (in term of > documentation). I think we should improve the feature processing > documentation: in which case should I use it, and how to use it. > > But overall +1 to me. > > Regards > JB > > On 19/03/2019 08:26, Grzegorz Grzybek wrote: > > Hello > > > > I was thinking about one scenario. In my custom distro, I'm using pax-web > > 7.3.3 (tech preview > > <https://groups.google.com/d/msg/ops4j/JP5L63Qh4u8/nPG1LN4HAAAJ>) which > > uses Undertow 2, Tomcat 9 and Servlet API 4. > > > > The "problem" is that maven-bundle-plugin, by default (and correctly) > > generates import ranges according to pom dependencies. So if pom has > > javax.servlet-api-3.1.0 dep, generated Import-Package header will have > > (correctly) "[3.1,4.0)" range which is the most natural range according > to > > semantic versioning. > > > > The problem is that with some deps (and servlet-api used in > > "@org.osgi.annotation.versioning.ConsumerType" mode is such dependency) > > you're safe to use newer version of the API. > > > > There were different approaches to this problem, see for example: > > https://bugs.eclipse.org/bugs/show_bug.cgi?id=385806 where bundles > either > > export packages in many versions or export lower version than one > matching > > directly JavaEE specification. For example, > > geronimo-servlet_3.0_spec-1.0.jar exports javax.servlet package with > > version 2.6 and 3.0. > > > > What I did (locally) is a little enhancement to new override&blacklisting > > mechanism configured in etc/org.apache.karaf.features.xml. I added this > > section for example: > > > > <bundleProcessing> > > <bundle location="mvn:org.eclipse.jetty*/*"> > > <add header="Processed-By" value="Karaf Bundle Processor" /> > > <clause header="Import-Package" name="javax.servlet" > > value='javax.servlet;version="[3.1.0,5)"' /> > > <clause header="Import-Package" name="javax.servlet.annotation" > > value='javax.servlet.annotation;version="[3.1.0,5)"' /> > > <clause header="Import-Package" name="javax.servlet.descriptor" > > value='javax.servlet.descriptor;version="[3.1.0,5)"' /> > > <clause header="Import-Package" name="javax.servlet.http" > > value='javax.servlet.http;version="[3.1.0,5)"' /> > > </bundle> > > </bundleProcessing> > > > > My goal was to be able to install for example "camel-websocket" feature > > which uses jetty which (at version 9.4) requires servlet API 3.1. > > > > FeaturesProcessor (the one that currently can override URIs of bundles or > > entire feature, blacklist features, bundle and repository URIs, has > > (locally in my branch) ability to transform a bundle when matching some > > criteria. > > > > In the above example, I can override all jetty bundles, so each > *individual > > clause* (unlike with wrap: where you work at header level) can be > changed. > > I can add full headers, remove headers, modify headers or modify > individual > > clauses. > > > > For example, to install jetty-util bundle, I had to wrap: it with: > > > > > wrap:mvn:org.eclipse.jetty/jetty-util/9.4.12.v20180830$overwrite=merge&Import-Package=javax.imageio,javax.naming,javax.naming.ldap,javax.net.ssl,javax.security.auth.x500,javax.xml.parsers,org.slf4j.*;resolution:=optional;version="[1.7.25,2)",javax.servlet.*;version="[3.1,5)" > > > > remembering to preserve existing Import-Package clauses. > > > > With XML configuration I can focus only on fixing javax.servlet.* import > > clauses. > > > > The transformed (repackaging + manifest change) bundles are stored in (by > > default) ${karaf.data}/repository-bpr (bpr = bundle processing) > directory, > > which is also explicitly prepended to > > org.ops4j.pax.url.mvn.defaultRepositories option used by maven resolver > > used by features service. > > > > Fitting into existing features processor mechanism, this change is > actually > > not that big. I see nice potential in it, but I'd very like to get your > > opinion on it - maybe additional ideas? Or problems with current idea? > > > > best regards > > Grzegorz Grzybek > > > > -- > Jean-Baptiste Onofré > jbono...@apache.org > http://blog.nanthrax.net > Talend - http://www.talend.com >