Hello niedz., 1 lis 2020 o 18:56 'paul stanley' via OPS4J <[email protected]> napisał(a):
> Hi Grzegorz, > > Sorry about the delay in getting back to you. > > I realise your concerns about sci's from different webapps interfering > with each other. However the SCI mechanism appears to be the way that the > other web technologies, such as JAXRS and SpringMVC have a chance to detect > and influence the creation of the servlet. > JaxRS and SpringMVC were designed to work in JavaEE runtime (or just flat classpath for non servlet applications) which has well defined hierarchical ClassLoader model, so scanning for SCIs is easy - just start with current ClassLoader (assigned to the WAR for example) and walk through parents. OSGi has also (very) well defined ClassLoader model - but it's not hierarchical, it's _network_ bidirectional graph of ClassLoaders... > > Given that ServiceLoader architecture is being used, is it unreasonable > that all possible instances for the SCI get asked to look at the bundle and > initialize the context is appropriate? > Hmm, I'm not sure I understand... SCI in onStartup() gets an instance of ServletContext and array of classes - it should not be bundle aware... > > If not, then we need another way to extend the WebExtender with other web > frameworks, allowing them to get involved with servlet creation. Which > does not include altering the webapp in some OSGI specific way. > I'm not sure we can extend the WebExtender (quite low level framework) with some web framework (SpringMVC, JaxRS, Wicket, Tapestry, name it - all more high level).... But fear not - the best way to detect proper SCIs (IMO) is simply to use WAB archives, so all jars from Bundle-ClassPath manifest header (which by default means all jars from /WEB-INF/lib of the bundle) are scanned for SCIs and web-fragment.xmls. regards Grzegorz Grzybek > > Cheers > Paul > On 30 Oct 2020, at 08:46, Grzegorz Grzybek <[email protected]> wrote: >> >> Hello >> >> czw., 29 paź 2020 o 19:50 Matt Pavlovich < [email protected]> napisał(a): >> >>> Paul-- >>> >>> You might checkout a BundleTracker. A BundleTracker is ensured to get a >>> callback for every bundle, regardless as to when your bundle started. With >>> a BundleListener, there is a race condition that you may not be activated >>> before some bundles that you care about. >>> >> >> It's not about bundle tracker or listener. Whiteboard implementation uses >> such tracker to ensure that when a bundle is gone, all associated contexts >> and web elements should be deregistered. >> It's more about which bundles should be scanned for >> ServletContainerInitializers. imagine you install two "sets" of bundles >> (e.g., Karaf features) - you don't want SCIs from one feature (web >> application) to be used in another feature/web application... >> >> regards >> Grzegorz Grzybek >> >> >>> >>> ref: >>> https://docs.osgi.org/specification/osgi.core/7.0.0/util.tracker.html#d0e52020 >>> >>> -Matt >>> >>> On Thursday, October 29, 2020 at 1:17:19 PM UTC-5 >>> [email protected] wrote: >>> >>>> >>>> Thanks Grzegorz. I know what you mean about doing my "normal job", I >>>> also have be careful as to what can be shared to the community. >>>> >>>> I realise that the ServiceLoader is a bit of a problem and I've already >>>> had to alter other standard services to be bundle-aware. Which is why I >>>> think implementing a Bundle Listener could be a better approach for the >>>> SCI's. >>>> >>>> I'm out of the office for a couple of weeks so I'm going to look >>>> prototyping a solution when I get back. >>>> >>>> Cheers >>>> Paul >>>> On 29 Oct 2020, at 13:28, Grzegorz Grzybek < [email protected]> >>>> wrote: >>>> >>>>> Hello >>>>> >>>>> You're generally right. I'm working on Pax Web 8 improvements (actual, >>>>> full implementation of OSGi CMPN R6+ Whiteboard specification + >>>>> HttpService >>>>> specification + Web Applications Specification) and I tackled the problem >>>>> of ServletContainerInitializers. >>>>> >>>>> The problem is that OSGi CMPN spec doesn't mention SCIs at all, only >>>>> Web Applications Specification generally assumes that "web bundle" should >>>>> be processed ("extended") by the implementation which involves web.xml >>>>> parsing + fragments parsing + (possibly) "classpath scanning". See for >>>>> example: >>>>> >>>>> A WAB can optionally contain a web.xml resource to specify additional >>>>>> configuration. This web.xml must be found with the Bundle >>>>>> *findEntries* method at the path WEB-INF/web.xml. The findEntries >>>>>> method includes fragments, allowing the web.xml to be provided by a >>>>>> fragment. >>>>>> >>>>> >>>>> So here there's nothing about "scanning other bundles" not referred >>>>> through "fragment" relationship. >>>>> >>>>> Also: >>>>> >>>>> Unlike a WAR, a WAB is not constrained to package classes and code >>>>>> resources in the WEB-INF/classes directory or dependent JARs in >>>>>> WEB-INF/lib/ only. These entries can be packaged in any way that's valid >>>>>> for an OSGi bundle as long as such directories and JARs are part of >>>>>> bundle >>>>>> class path as set with the Bundle-ClassPath header and any attached >>>>>> fragments. JARs that are specified in the Bundle-ClassPath header are >>>>>> treated like JARs in the WEB-INF/lib/ directory of the Servlet >>>>>> specification. Similarly, any directory that is part of the >>>>>> Bundle-ClassPath header is treated like WEB-INF/classes directory of the >>>>>> Servlet specification. >>>>>> >>>>> >>>>> So again - you can "bring" additional libraries to your "bundle >>>>> classpath" by referring them in "Bundle-ClassPath" header. No scanning of >>>>> everything (that's for example tracked by BundleListener). >>>>> >>>>> And about java.util.ServiceLoader (which should in theory be a >>>>> suggestion to how ServletContainerInitializer "services" are found), >>>>> "java.util.ServiceLoader#load(java.lang.Class<S>, java.lang.ClassLoader)" >>>>> method simply uses the passed classLoader and the other "load()" version >>>>> uses TCCL. Neither of these methods scan ALL classloaders (all bundles in >>>>> OSGi). >>>>> >>>>> In Pax Web 8 I'm definitely going to solve this problem - for now, a >>>>> bundle that registered "a context" >>>>> (org.osgi.service.http.context.ServletContextHelper) is an "entry point" >>>>> to >>>>> classLoader "mesh" where all are checked for SCIs. >>>>> >>>>> My Pax Web 8 refactoring is taking its shape at >>>>> https://github.com/ops4j/org.ops4j.pax.web/tree/master-improvements >>>>> branch, but I have to do my normal job a bit ;) So please be patient. >>>>> >>>>> regards >>>>> Grzegorz Grzybek >>>>> >>>>> >>>>> czw., 29 paź 2020 o 14:13 'paul stanley' via OPS4J < >>>>> [email protected]> napisał(a): >>>>> >>>>>> Hello. >>>>>> >>>>>> I'm tracing this through to try and understand why Jersey Servlet >>>>>> Initializer is not invoked for a pure Jaxrs applications running in Karaf >>>>>> 4.3.0. >>>>>> >>>>>> It appears the way that the ServletContainerInitializerScanner in the >>>>>> pax-web-api has a fundamental design flaw when it searches bundles for >>>>>> instances of the /META-INF/services/ ServletContainerInitializerScanner >>>>>> file. Namely that it only searches dependent bundles of the one that is >>>>>> being initialised. As the implementation of any service is meant to be >>>>>> hidden by the API, it means that you will never be able to initialise any >>>>>> web servlet. As such the pax-jetty-web adds the bodge of wiring-in >>>>>> itself >>>>>> to all web-context so its contextInitializer code can be discovered, but >>>>>> no >>>>>> other implementations. >>>>>> >>>>>> Rather than performing a bundle scan each time, surely jetty should >>>>>> be implementing the bundle listener pattern and have the set of servlet >>>>>> initializers that are available in the platform? Or am I missing >>>>>> something? >>>>>> >>>>>> Cheers, >>>>>> >>>>>> Paul >>>>>> >>>>>> -- >>>>>> -- >>>>>> ------------------ >>>>>> OPS4J - http://www.ops4j.org - [email protected] >>>>>> >>>>>> --- >>>>>> You received this message because you are subscribed to the Google >>>>>> Groups "OPS4J" group. >>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>> send an email to [email protected]. >>>>>> To view this discussion on the web visit >>>>>> https://groups.google.com/d/msgid/ops4j/e9d0b4ab-33d7-4895-8a0f-e6d55e3e3b43n%40googlegroups.com >>>>>> <https://groups.google.com/d/msgid/ops4j/e9d0b4ab-33d7-4895-8a0f-e6d55e3e3b43n%40googlegroups.com?utm_medium=email&utm_source=footer>. >>>>>> >>>>>> >>>>> -- >>>>> -- >>>>> ------------------ >>>>> OPS4J - http://www.ops4j.org - [email protected] >>>>> >>>>> --- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "OPS4J" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to [email protected]. >>>>> >>>> To view this discussion on the web visit >>>>> https://groups.google.com/d/msgid/ops4j/CAAdXmhqcqH3h1bhJhYLb1%2B08u3dcSzFE%2BEYpe%2B62O7CbmMZHGQ%40mail.gmail.com >>>>> <https://groups.google.com/d/msgid/ops4j/CAAdXmhqcqH3h1bhJhYLb1%2B08u3dcSzFE%2BEYpe%2B62O7CbmMZHGQ%40mail.gmail.com?utm_medium=email&utm_source=footer>. >>>>> >>>>> >>>> -- >>> -- >>> ------------------ >>> OPS4J - http://www.ops4j.org - [email protected] >>> >>> --- >>> You received this message because you are subscribed to the Google >>> Groups "OPS4J" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/ops4j/a2363134-86ad-40e9-869b-36885ac68083n%40googlegroups.com >>> <https://groups.google.com/d/msgid/ops4j/a2363134-86ad-40e9-869b-36885ac68083n%40googlegroups.com?utm_medium=email&utm_source=footer>. >>> >>> >> -- >> -- >> ------------------ >> OPS4J - http://www.ops4j.org - [email protected] >> >> --- >> You received this message because you are subscribed to the Google Groups >> "OPS4J" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/ops4j/CAAdXmhpRfntRwzx2oykWjf56AJtWPH2nFD59dfLBFWLO5NpCJA%40mail.gmail.com >> <https://groups.google.com/d/msgid/ops4j/CAAdXmhpRfntRwzx2oykWjf56AJtWPH2nFD59dfLBFWLO5NpCJA%40mail.gmail.com?utm_medium=email&utm_source=footer>. >> >> > -- > -- > ------------------ > OPS4J - http://www.ops4j.org - [email protected] > > --- > You received this message because you are subscribed to the Google Groups > "OPS4J" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/ops4j/0ba73d25-16c8-4ac6-8bfd-ad9404c56664%40googlemail.com > <https://groups.google.com/d/msgid/ops4j/0ba73d25-16c8-4ac6-8bfd-ad9404c56664%40googlemail.com?utm_medium=email&utm_source=footer> > . > -- -- ------------------ OPS4J - http://www.ops4j.org - [email protected] --- You received this message because you are subscribed to the Google Groups "OPS4J" group. 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