Re: [ovirt-devel] Question/thoughts about our engine logging framework

16 Jun 2014


      ----- Original Message -----
...
From: "Martin Perina" <mperina@redhat.com>
To: "Alon Bar-Lev" <alonbl@redhat.com>
Cc: devel@ovirt.org
Sent: Monday, June 16, 2014 4:49:57 PM
Subject: Re: [ovirt-devel] Question/thoughts about our engine logging framework
----- Original Message -----
...
From: "Alon Bar-Lev" <alonbl@redhat.com>
To: "Martin Perina" <mperina@redhat.com>
Cc: devel@ovirt.org
Sent: Monday, June 16, 2014 3:26:00 PM
Subject: Re: [ovirt-devel] Question/thoughts about our engine logging
framework
----- Original Message -----
...
From: "Martin Perina" <mperina@redhat.com>
To: "Alon Bar-Lev" <alonbl@redhat.com>
Cc: devel@ovirt.org
Sent: Monday, June 16, 2014 4:22:16 PM
Subject: Re: [ovirt-devel] Question/thoughts about our engine logging
framework
----- Original Message -----
...
From: "Alon Bar-Lev" <alonbl@redhat.com>
To: "Martin Perina" <mperina@redhat.com>
Cc: devel@ovirt.org, "Greg Sheremeta" <gshereme@redhat.com>
Sent: Sunday, June 15, 2014 7:44:22 PM
Subject: Re: [ovirt-devel] Question/thoughts about our engine logging
framework
----- Original Message -----
...
From: "Martin Perina" <mperina@redhat.com>
To: "Alon Bar-Lev" <alonbl@redhat.com>
Cc: devel@ovirt.org, "Greg Sheremeta" <gshereme@redhat.com>
Sent: Sunday, June 15, 2014 8:17:13 PM
Subject: Re: [ovirt-devel] Question/thoughts about our engine logging
framework
----- Original Message -----
...
From: "Alon Bar-Lev" <alonbl@redhat.com>
To: "Martin Perina" <mperina@redhat.com>
Cc: devel@ovirt.org, "Greg Sheremeta" <gshereme@redhat.com>
Sent: Sunday, June 15, 2014 6:27:09 PM
Subject: Re: [ovirt-devel] Question/thoughts about our engine
logging
framework
----- Original Message -----
> From: "Martin Perina" <mperina@redhat.com>
> To: "Alon Bar-Lev" <alonbl@redhat.com>
> Cc: devel@ovirt.org, "Greg Sheremeta" <gshereme@redhat.com>
> Sent: Sunday, June 15, 2014 7:19:15 PM
> Subject: Re: [ovirt-devel] Question/thoughts about our engine
> logging
> framework
> 
> 
> 
> ----- Original Message -----
> > From: "Alon Bar-Lev" <alonbl@redhat.com>
> > To: "Martin Perina" <mperina@redhat.com>
> > Cc: "Greg Sheremeta" <gshereme@redhat.com>, devel@ovirt.org
> > Sent: Sunday, June 15, 2014 5:07:28 PM
> > Subject: Re: [ovirt-devel] Question/thoughts about our engine
> > logging
> > framework
> > 
> > 
> > 
> > ----- Original Message -----
> > > From: "Martin Perina" <mperina@redhat.com>
> > > To: "Greg Sheremeta" <gshereme@redhat.com>
> > > Cc: devel@ovirt.org
> > > Sent: Sunday, June 15, 2014 5:34:51 PM
> > > Subject: Re: [ovirt-devel] Question/thoughts about our engine
> > > logging
> > > framework
> > > 
> > > 
> > > 
> > > ----- Original Message -----
> > > > From: "Greg Sheremeta" <gshereme@redhat.com>
> > > > To: "Yair Zaslavsky" <yzaslavs@redhat.com>
> > > > Cc: devel@ovirt.org
> > > > Sent: Sunday, June 15, 2014 4:25:54 PM
> > > > Subject: Re: [ovirt-devel] Question/thoughts about our
> > > > engine
> > > > logging
> > > > framework
> > > > 
> > > > 
> > > > 
> > > > ----- Original Message -----
> > > > > From: "Eli Mesika" <emesika@redhat.com>
> > > > > To: "Yair Zaslavsky" <yzaslavs@redhat.com>
> > > > > Cc: devel@ovirt.org
> > > > > Sent: Sunday, June 15, 2014 10:02:15 AM
> > > > > Subject: Re: [ovirt-devel] Question/thoughts about our
> > > > > engine
> > > > > logging
> > > > > framework
> > > > > 
> > > > > 
> > > > > 
> > > > > ----- Original Message -----
> > > > > > From: "Vojtech Szocs" <vszocs@redhat.com>
> > > > > > To: "Martin Perina" <mperina@redhat.com>
> > > > > > Cc: devel@ovirt.org
> > > > > > Sent: Friday, June 13, 2014 12:57:49 PM
> > > > > > Subject: Re: [ovirt-devel] Question/thoughts about our
> > > > > > engine
> > > > > > logging
> > > > > > framework
> > > > > > 
> > > > > > 
> > > > > > 
> > > > > > ----- Original Message -----
> > > > > > > From: "Martin Perina" <mperina@redhat.com>
> > > > > > > To: "Yair Zaslavsky" <yzaslavs@redhat.com>
> > > > > > > Cc: devel@ovirt.org
> > > > > > > Sent: Friday, June 13, 2014 10:43:59 AM
> > > > > > > Subject: Re: [ovirt-devel] Question/thoughts about
> > > > > > > our
> > > > > > > engine
> > > > > > > logging
> > > > > > > framework
> > > > > > > 
> > > > > > > Hi Yair,
> > > > > > > 
> > > > > > > I had in my mind to clean up logging framework mess
> > > > > > > for
> > > > > > > quite
> > > > > > > some
> > > > > > > time
> > > > > > > :-)
> > > > > > > Currently this is the usage of logging frameworks in
> > > > > > > engine
> > > > > > > classes:
> > > > > > > 
> > > > > > > java.util.logging.Logger              6.8%
> > > > > > > org.apache.commons.logging.Log        7.8%
> > > > > > > org.apache.log4j.Logger              13.6%
> > > > > > > org.ovirt.engine.core.utils.log.Log  68.8%
> > > > > > > org.slf4j.Logger                      2.9%
> > > > > > > 
> > > > > > > I think we should definitely use only 1 logging
> > > > > > > framework
> > > > > > > for
> > > > > > > the
> > > > > > > whole
> > > > > > > engine!
> > > > > > > 
> > > > > > > So +1 to slf4j from me.
> > > > > > 
> > > > > > +1 from me as well.
> > > > > 
> > > > > +1
> > > > > 
> > > > +1 to slf4j. I started using that exclusively in Java
> > > > projects
> > > > 4
> > > > years
> > > > ago
> > > > :)
> > > > 
> > > > Just be careful if we're introducing it as a new
> > > > dependency.
> > > > (It's
> > > > provided
> > > > by Fedora, but there might be conflicts if JBoss/Wildfly
> > > > uses
> > > > it.
> > > > We
> > > > should
> > > > use that same version, if it does.)
> > > 
> > > We already have a dependency to slf4j 1.7.5 in the root
> > > pom.xml.
> > > And
> > > AFAIK
> > > 1.7.2 is a part of EAP 6.
> > 
> > The jboss we are using provides slf4j-1.6.1, while it seems to
> > be
> > patched
> > to
> > support varargs[1] as 1.7.x.
> 
> Ha, you are right, inside JBoss it works, because they did the
> same
> thing
> as
> with
> log4j. They provide same classes as slf4j, but with their own
> different
> implementation with JBoss Logging backend :-(
> 
> So if you compile with slf4j 1.7, you can use varargs even when
> JBoss
> tries
> to tell
> us it provides slf4j 1.6 ...
> 
> > As standalone at fedora there is slf4j which is compatible and
> > at
> > rhel
> > there
> > is slf4j-eap6 both are 1.7.x.
> > However for centos we use jpackage which provides only
> > 1.6.1[2].
> > So for standalone packages we may experience issues if were
> > build
> > using
> > varargs.
> > 
> > [1] logger.debug("format", obj1, obj2, obj3, ...)
> > [2] http://jpackage.org/browser/rpm.php?jppversion=6.0&id=12435
> 
> AFAIK the only non JBoss usage of logging is at engine-config and
> engine-manage-domains.
> So we have 2 options:
> 
>   1) Use log4j in engine-config and engine-manage-domains
>   (current
>   status)
>   and use
>      slf4j in the rest of engine
> 
>   2) Package slf4j 1.7.x as our dependency
> 
> I would prefer option 1).
>
No... we use jboss modules within these, so you actually using
jboss
version.
Not entirely true. We are using JBoss version of log4j to configure
logging.
But we cannot use slf4j provided by JBoss, because it can use as a
backend
only JBoss Logging and not log4j. I just verified that if slf4j is
used
in engine-manage-domains, it's not logged to the file configured by
log4j.
...
The only one that does not use jboss modules is dwh, in which we do
not
control logging anyway.
We just need to make sure that standalone application either use
commons-logging (primitive) or slf4j-1.6.x for now.
And in either case to use java.util.loggings as infa and not log4j
if
not
too
late for that.
In java.utils.logging you cannot use varargs in simple way (which is
for
me
one of the main reason to use slf4j):
log.info("Hello: {} {} {}", p1, p2, p3);
but you have to create new array of params:
log.info("Hello: {} {} {}", new Object[] { p1, p2, p3});
or format message outside logging framework:
log.info(String.format("Hello: %s %s %s", p1, p2, p3));
And this "external formatting" is the only way for commons-logging
framework.
You did not understand.
Well, I'm not sure I understand even now, but see my response :-)
...
1. use log4j or apache commons within application.
That's not a good idea because both doesn't support simple varargs.
We want use slf4j to be able to use this:
log.info("Hello: {} {} {}", p1, p2, p3);
I am sorry, had a typo... it should have been:
1. use slf4j or apache commons within application.
OK, now I understand, so if agreed then we will use slf4j.
So if we agree to slf4j, I plan to use slf4j in engine (the only
exception is java.logging in GWT related parts of code), remove
dependency to other logging frameworks (log4j, commons-logging)
and remove internal logging framework (org.ovirt.engine.core.utils.log)
...
...
...
2. use java.logging as logging infra.
Well, AFAIK JBoss reimplements java.logging backend and redirects
it to its own backend (JBoss Logging). No sure, if we will be able
(or want) to bypass this redirection and use java.logging as backend
for engine. Not to mention, there will always be server.log for JBoss
infra logging.
And for engine-manage-domains and engine-config we would have to
drop command line configuration using log4j introduced in 3.5 and
for next version change it to java.logging configuration
So personally I don't see any benefit of this change for users nor
developers ...
yes, and drop the usage of log4j entirely.
OK, so migrate from log4j to java.logging backend in engine-manage-domains
and engine-config ...
Right.

I opened a bug[1]

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1109871
...
...
...
...
...
...
> Btw in RHEL7 there is packaged slf4j 1.7.5
> 
> > 
> > > 
> > > > 
> > > > > > 
> > > > > > Note that GWT UI code uses java.util.logging
> > > > > > exclusively
> > > > > > to
> > > > > > do
> > > > > > all
> > > > > > logging.
> > > > > > (GWT emulates java.util.logging API and provides log
> > > > > > handlers
> > > > > > for
> > > > > > use
> > > > > > on
> > > > > > client side such as console.log() or
> > > > > > stdout/DevMode-during-debug
> > > > > > handlers.)
> > > > > > 
> > > > > > > 
> > > > > > > And once we agree to 1 logging framework, I can start
> > > > > > > preparing
> > > > > > > patches
> > > > > > > to
> > > > > > > use it.
> > > > > > > 
> > > > > > > ----- Original Message -----
> > > > > > > > From: "Yair Zaslavsky" <yzaslavs@redhat.com>
> > > > > > > > To: devel@ovirt.org
> > > > > > > > Sent: Friday, June 13, 2014 8:15:55 AM
> > > > > > > > Subject: [ovirt-devel] Question/thoughts about our
> > > > > > > > engine
> > > > > > > > logging
> > > > > > > > framework
> > > > > > > > 
> > > > > > > > Hi all,
> > > > > > > > During my recent work on AAA, I was suggested by
> > > > > > > > Juan
> > > > > > > > Hernandez
> > > > > > > > to
> > > > > > > > use
> > > > > > > > slf4j
> > > > > > > > logging framework which serves as a facade for
> > > > > > > > other
> > > > > > > > logging
> > > > > > > > frameworks
> > > > > > > > (including java utils logging which is now used by
> > > > > > > > jboss),
> > > > > > > > log4j
> > > > > > > > and
> > > > > > > > others.
> > > > > > > > I have accepted Juan's offer, and then when looking
> > > > > > > > at
> > > > > > > > our
> > > > > > > > LogFactory
> > > > > > > > class
> > > > > > > > I
> > > > > > > > have noticed we use commons logging.
> > > > > > > > 
> > > > > > > > Several thoughts/questions -
> > > > > > > > A. Why continue use our own wrapper as slf4j is
> > > > > > > > already
> > > > > > > > a
> > > > > > > > facade.
> > > > > > > > b. I think we should move cross java code to slf4j.
> > > > > > > > What
> > > > > > > > do
> > > > > > > > you
> > > > > > > > think
> > > > > > > > on
> > > > > > > > this
> > > > > > > > point?
> > > > > > > > 
> > > > > > > > Some reading material -
> > > > > > > > 
> > > > > > > > http://javarevisited.blogspot.com.au/2013/08/why-use-sl4j-over-log4j-for-log...
> > > > > > > > http://stackoverflow.com/questions/3222895/what-is-the-issue-with-the-runtim...
> > > > > > > > 
> > > > > > > > 
> > > > > > > > 
> > > > > > > > Yair
> > > > > > > > _______________________________________________
> > > > > > > > Devel mailing list
> > > > > > > > Devel@ovirt.org
> > > > > > > > http://lists.ovirt.org/mailman/listinfo/devel
> > > > > > > > 
> > > > > > > _______________________________________________
> > > > > > > Devel mailing list
> > > > > > > Devel@ovirt.org
> > > > > > > http://lists.ovirt.org/mailman/listinfo/devel
> > > > > > > 
> > > > > > _______________________________________________
> > > > > > Devel mailing list
> > > > > > Devel@ovirt.org
> > > > > > http://lists.ovirt.org/mailman/listinfo/devel
> > > > > > 
> > > > > _______________________________________________
> > > > > Devel mailing list
> > > > > Devel@ovirt.org
> > > > > http://lists.ovirt.org/mailman/listinfo/devel
> > > > > 
> > > > _______________________________________________
> > > > Devel mailing list
> > > > Devel@ovirt.org
> > > > http://lists.ovirt.org/mailman/listinfo/devel
> > > > 
> > > _______________________________________________
> > > Devel mailing list
> > > Devel@ovirt.org
> > > http://lists.ovirt.org/mailman/listinfo/devel
> > > 
> > 
>