The question to answer is whether it would be worthwhile "as is" to be
donated to Apache Felix as a starting point? If so, figuring out ways to
improve it can happen after the fact. If not, then there isn't much else
to discuss.
-> richard
On 4/17/18 08:53 , Neil Bartlett wrote:
I like the general idea but, like Guillaume, I feel maybe this should be
implemented at a lower level. The core `SystemReadinessMonitorImpl` and the
rootcause command are implemented as DS components and configured via
Config Admin... but what if SCR and/or ConfigAdmin are unavailable or not
working?
I'm also not sure about the way in which checks are defined and extended.
Only the application knows what "should" be started, but this can be
defined at the application level using a DS component that has dependencies
on the necessary services, config etc. That DS component would provide a
SystemReady service when it has decided the system is ready.
Thus I think your framework can be boiled down to something simpler:
* An exported SystemReady service interface, which should appear within a
configurable timeout;
* The root cause analysis tool, which is something I have always wanted to
have and I hope your implementation works as well as described!
Regards,
Neil
On Tue, Apr 17, 2018 at 1:37 PM, Andrei Dulvac <[email protected]> wrote:
Hi Guillaume.
Thanks!
There's the OOTB ServicesCheck check that can be configured with a list of
services [0].
We were thinking we could add the mandatory checks there through
configuration.
The fact that the system can initially green, because no checks are present
is VERY valid.
We try to mediate that with the ServicesCheck and by making sure the
monitor waits for the framework to be up before reporting anything other
than YELLOW.
Hope I got the question and suggestion right :D
- Andrei
---
[0]
https://github.com/dulvac/system-readiness/blob/master/
src/main/java/org/apache/sling/systemreadiness/core/
impl/ServicesCheck.java#L59
On Tue, Apr 17, 2018 at 2:16 PM Guillaume Nodet <[email protected]> wrote:
I like it a lot, the API is simple and extensible enough. Really nice
work
!
I'm just a bit nervous about having such a low-level component depend on
an
external extender...
I think it's missing one bit though: some kind of expectations. I.e. it
checks existing stuff, but it does not cover missing stuff. I suppose it
could be implemented specifically using custom checks, but I think there
is
still a hole, which is the fact that those custom checks are not
available. So I wonder if there should be an additional built-in check
that would grab a configuration entry, turn that into a list of mandatory
checks and be green if all those check are available, yellow/red
otherwise. This would ensure your container does not switch between
green/yellow while the container is booting/provisioning.
2018-04-17 10:02 GMT+02:00 Christian Schneider <[email protected]
:
Dear Felix community,
during the last weeks Andrei Dulvac and I worked on a small framework
to
check if an OSGi based system is fully up.
Our work originated in testing sling modules and whole sling instances.
We
soon found though that the concept is more general than sling and can
be
applied to any OSGi based system.
The system readiness framework has a SystemReadinessMonitor service
that
reports the aggregated state of the system. It delegates to
SystemReadinessCheck services that each check for a certain aspect. We
implemented a first check based on a list of expected top level
services.
The system can be customised by adding specific checks for your
application. For example we plan to add sling specific checks inside
the
sling project.
In addition to simply detecting if the system is ready we also created
a
DS
based root cause analysis that can be very helpful to detect why a set
of
components does not come up as expected.
We would like to donate this project to the Apache Felix project as it
might get more attention there by people that are not related to sling.
The
project is Apache licensed from the start and we already got a basic
documentation as well as good test coverage.
We currently host it in this github repository:
https://github.com/dulvac/system-readiness
The packages are still mentioning sling but of course we would change
this
to felix if this community is interested in the donation.
Best regards
Christian and Andrei
--
--
Christian Schneider
http://www.liquid-reality.de
Computer Scientist
http://www.adobe.com
--
------------------------
Guillaume Nodet
