Georg Henzler created SLING-7790:
------------------------------------

             Summary: Allow for synchronous installation of bundles and 
configurations via install hook
                 Key: SLING-7790
                 URL: https://issues.apache.org/jira/browse/SLING-7790
             Project: Sling
          Issue Type: New Feature
          Components: Installer
            Reporter: Georg Henzler
            Assignee: Georg Henzler


Normally bundles configurations are installed asynchronously after a bundle is 
saved to the JCR during package installation (vault packages). This is due to 
the backgroundThread that the OsgiInstallerImpl is using. Since the 
introduction of the pauseInstallation signal node SLING-3747, the installation 
of bundles and configurations is forced to after the completed vault package 
installation. This behaviour also means that the package dependency can be 
declared, but they are not effective on "contained bundle level" but only on 
JCR content level. The following is not possible today:

Complete Package with sub packages:
* Package A (containing Bundle A)
* Package B (containing Bundle B) with dependency to bundle A

If it is just a OSGi package dependency from Bundle B to bundle A the 
installation order does not matter (the OSGi framework will sort it out). 
However if the content of package B has a dependency to bundle A (think custom 
oak restrictions [1] or install hooks referenced) there will be an error. 

To allow for those cases and to avoid manual steps (not providing a complete 
package often means exactly that), it would be good to have a means to install 
contained bundles of a package synchronously. This can be achieved by a fairly 
simple install hook that "pre-installs" the contained InstallableResources with 
the correct digest to the via the OsgiInstaller. The subsequent call of 
sling-org-apache-sling-installer-provider-jcr will just update the already 
installed resource again with the same digest (which will not cause any action 
in the system). 

Obviously this mechanism should only be used where needed and only for 
configurations and bundles that are safe to install (that will never restart 
any of the base services), using the install hook makes the mechanism "opt-in". 

[1] 
https://sling.apache.org/documentation/bundles/sling-oak-restrictions.html
https://jackrabbit.apache.org/oak/docs/security/authorization/restriction.html#pluggability






--
This message was sent by Atlassian JIRA
(v7.6.3#76005)

Reply via email to