Hi everyone, We got several user feedback, complaining about unexpected and cascaded (unrelated) refresh while installing features.
As reminder, a refresh can happen when: - bundle A imports package foo:1 and a bundle provides newer foo package version. In that case, the features service will refresh A to use the newest package version. - bundle A has an optional import to package foo and a bundle provides this package. In that case, the features service will refresh A to actually use the import as it’s a "resolved" optional. - bundle A is wired to bundle B (from a package perspective or requirement) and B is refreshed. In that case, the features service will refresh A as B is itself refreshed (for the previous reasons for instance). This can cause "cascading" refresh. A refresh means that a bundle can be restarted (if the bundle contains an activator or similar (DS component, blueprint bundle)). In this PR https://github.com/apache/karaf/pull/1287 <https://github.com/apache/karaf/pull/1287>, I propose to introduce a new property autoRefresh in etc/org.apache.karaf.features.cfg to disable the auto refresh by the features service (and let the user decides when he wants to trigger refresh with bundle:refresh command for instance). I propose to keep autoRefresh=true on 4.2.x and turn autoRefresh=false on 4.3.x. Thoughts ? On the other hand (and to prepare the "path" to Karaf5), I have created a new "simple features service" (PR will be open soon) that: - just take the features definition in order (ignoring start level) - ignore requirement/capability (no resolver) - no auto refresh Basically, if you have the following feature definition: <feature name="foo" version="1.0"> <feature>bar</feature> <bundle>A</bundle> <bundle>B</bundle> </feature> The features service will fully install/start bar feature first, then bundle A, then bundle B. To use this "simple features services, you just have to replace org.apache.karaf.features.core by org.apache.karaf.features.simple bundle in etc/startup.properties (or custom distribution). It’s similar to the Karaf 5 extension behavior (I will share complete details about Karaf 5 and its concepts (module, extension, …) very soon, but that’s another thread ;)). The big advantages of this approach is: - predictable/deterministic provisioning (if it works fine, it works again) - faster deployment (I estimated the gain to about 70%) Thoughts ? If you agree, I will move forward on both tasks. Thanks, Regards JB
