[slf4j-user] Slf4j 2.0 future

Fri Jun 18 03:07:51 CEST 2021

Hi Ceki,

I'm also a person using SLF4J 2.0-alpha to work with the Java module.

I need a stable SLF4J release supporting the Java module, however, the
fluent logging API isn't necessary for me
because I think its design and merit still needs discussion to be
stabilized.

In my understanding
<http://mailman.qos.ch/pipermail/slf4j-user/2020-August/001748.html>, 1.8
already supports the Java module, and 2.0 additionally includes the fluent
logging API.
Then why not release a stable 1.8.0 first, then we can provide stable
support for the Java module (and OSGi).

We can also secure a timeslot to brush up 2.0 new features including fluent
logging API... now we have
several precedents such as google/flogger
<https://github.com/google/flogger> and log4j2
<https://logging.apache.org/log4j/2.x/manual/logbuilder.html>, probably we
can learn from their usage.

Thanks in advance. Regards

***
Kengo TODA
skypencil at gmail.com

On Tue, Jun 15, 2021 at 10:23 AM Joakim Erdfelt <joakim.erdfelt at gmail.com>
wrote:

> Jetty includes slf4j-api-2.0.0.alpha.jar in it's jetty-home
> (distribution), and we've built it specifically against the slf4j version
> 2.0.0 series.
>
> https://github.com/eclipse/jetty.project/blob/jetty-11.0.5/pom.xml#L22
>
>
> https://repo1.maven.org/maven2/org/eclipse/jetty/jetty-home/10.0.5/jetty-home-10.0.5.tar.gz
>
> [jetty-home-10.0.5]$ find . -name "*slf4j*"
> ./lib/logging/jetty-slf4j-impl-10.0.5.jar
> ./lib/logging/slf4j-api-2.0.0-alpha1.jar
> ./modules/logging/slf4j.mod
>
> We don't use the fluent logging API, as we were unhappy with the extra GC
> it seems to be generating.
>
> We have full JPMS support with slf4j-api-2.0.0-alph1.jar without any extra
> work on our part.
> Works well, even with the alternate bridge APIs.
>
>
> https://github.com/eclipse/jetty.project/blob/jetty-11.0.5/jetty-slf4j-impl/src/main/java/module-info.java#L22
>
> https://github.com/eclipse/jetty.project/blob/jetty-11.0.5/jetty-server/src/main/java/module-info.java#L25
>
> https://github.com/eclipse/jetty.project/blob/jetty-11.0.5/jetty-deploy/src/main/java/module-info.java#L25
>
> We even have automated unit testing of our JPMS layers with logging
> enabled! :-)
>
> As for OSGI, the sfl4j-api-2.0.0-alpha1.jar lacks the OSGI manifest
> `Requires-Capability` for the ServiceLoader layer.
> That's an unfortunate missing piece in the 2.0.0-alpha1 release.
>
> We hacked in that missing serviceloader manifest entry into our own
> jetty-slf4j-impl.jar.
>
> https://github.com/eclipse/jetty.project/blob/jetty-11.0.5/jetty-slf4j-impl/pom.xml#L42-L45
>
> And we have an osgi bundle fragment that we can hack the manifest into for
> testing reasons.
> Also, for our paxweb testing, we have a snippet that adds that service
> loader requirement.
>
>
> https://github.com/eclipse/jetty.project/blob/jetty-10.0.3/jetty-osgi/test-jetty-osgi/src/test/java/org/eclipse/jetty/osgi/test/TestOSGiUtil.java#L164-L167
>
>         //the slf4j-api jar does not have support for ServiceLoader in
> osgi in its manifest, so add it now
>
> res.add(wrappedBundle(mavenBundle().groupId("org.slf4j").artifactId("slf4j-api").versionAsInProject())
>
> .instructions("Require-Capability=osgi.serviceloader;filter:=\"(osgi.serviceloader=org.slf4j.spi.SLF4JServiceProvider)\",osgi.extender;filter:=\"(osgi.extender=osgi.serviceloader.processor)\"")
>             .overwriteManifest(OverwriteMode.MERGE)
>             .start());
>
> The work done in SLF4J-457 for OSGi is right on the money, and the
> associated PR and commit fix it nicely.
>
> As for Eclipse IDE and slf4j-api-2.0.0-alpha1, they had to recently (this
> week) yank it out due to both some conflicts in other libraries (i'm
> unclear what those conflicts entailed), and the general "we think slf4j is
> an abandoned project" attitude.
> You can see some of the conversations around this at
> https://www.eclipse.org/lists/cross-project-issues-dev/threads.html#18493
> We, Eclipse Jetty, had to even expand our declared Import-Package to allow
> using 1.7.x upwards of slf4j to allow Eclipse IDE to get past these issues
> for their current release.
> Thankfully, our main codebase isn't using the slf4j fluent API which means
> we are still backwards compatible with slf4j 1.7 for OSGi users, but we'd
> like to encourage & foster slf4j 2.0.0 as the future direction, even there.
>
> - Joakim
>
>
> On Mon, Jun 14, 2021 at 4:33 AM Ceki <ceki at qos.ch> wrote:
>
>>
>> Hi Joakim,
>>
>> Indeed, I am aware that Jetty has been supporting/using slf4j since
>> early on. Thank you!
>>
>> I was not aware that Jetty and Eclipse IDE was using slf4j 2.0.0-alpha.
>>
>> As you are probably aware, slf4j 2.0 introduces a fluent logging API
>> which is quite an enhancement with respect to the traditional logging
>> API. Are you using the fluent API at all?
>>
>> Thank you for your offer to help. It is much appreciated.
>>
>> Do you see any issues that are blocking on your end? With slf4j's JPMS
>> support perhaps? Maybe OSGi?
>>
>> More concretely, in SLF4J-457, see [1], the MANIFEST.MF file was
>> modified [2] by adding a "Require-Capability:" statement, see [2]. How
>> safe is this addition in OSGi environments? In non-OSGi environments?
>>
>> Best regards,
>>
>>
>> [1] https://jira.qos.ch/browse/SLF4J-457
>> [2] https://github.com/qos-ch/slf4j/commit/4a1d5194fe
>>
>> --
>> Ceki
>>
>>
>>
>>
>> On 10.06.2021 14:41, Joakim Erdfelt wrote:
>> > Hey Ceki,
>> >
>> > Hi from the Eclipse Jetty project.
>> > We've been supporting slf4j in Eclipse Jetty since Jetty 5.x (and slf4j
>> > 1.1.0)
>> >
>> > Recently (in the past 2 years), we moved to slf4j 2.0 because it was
>> our
>> > favorite logging facade and had support for JPMS. (proper JPMS support
>> > was the huge deciding factor)
>> > We did this with our Jetty 10.x series (and Jetty 11.x series), which
>> > have had 4 stable releases each so far.
>> > We have a JPMS web server with a JPMS based logging facade.
>> >
>> > We've had great success, and even wrote our own minimal implementation
>> > of slf4j-api 2.0 that we use for our minimal deployments (even
>> > supporting JPMS).
>> >
>> https://github.com/eclipse/jetty.project/tree/jetty-10.0.x/jetty-slf4j-impl
>> > <
>> https://github.com/eclipse/jetty.project/tree/jetty-10.0.x/jetty-slf4j-impl
>> >
>> >
>> > This in turn has encouraged others to adopt slf4j 2.0 as well,
>> including
>> > the Eclipse IDE itself.
>> > This means we now have an OSGi manifest requirement that is being
>> worked
>> > out as I write this.
>> >
>> > We have hundreds of thousands of installations of Eclipse Jetty 10+
>> > active around the world now, all with slf4j 2.0 running.
>> >
>> > However, there's been a slow drum beat of criticism that says slf4j
>> > looks like a dead project with an absent developer community.
>> >
>> > I want to see slf4j survive and continue to be the awesome project
>> we've
>> > grown to love.
>> >
>> > Is there anything you need help with?
>> > I'll be happy to help.
>> > Do you need help addressing or verifying anything from the JIRA issues
>> > to progress?
>> >
>> > Thanks again,
>> > Joakim Erdfelt (Eclipse Jetty committer)
>> >
>>
>> --
>> Ceki Gülcü
>> _______________________________________________
>> slf4j-user mailing list
>> slf4j-user at qos.ch
>> http://mailman.qos.ch/mailman/listinfo/slf4j-user
>
> _______________________________________________
> slf4j-user mailing list
> slf4j-user at qos.ch
> http://mailman.qos.ch/mailman/listinfo/slf4j-user
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qos.ch/pipermail/slf4j-user/attachments/20210618/21f43c09/attachment.html>