>From what I can tell, alternative logging backend can be distributed as an extension that is dropped into M2_HOME/lib/ext folder.
The only real limitation is that you can't provide default logging configuration as part of the extension. This is due to odd/wrong order of entries in m2.conf file, but I didn't feel too strong about fixing it. https://issues.apache.org/jira/browse/MNG-5836 -- Regards, Igor On Wed, Oct 7, 2015, at 08:39 AM, Arnaud Héritier wrote: > Hi Igor, > > I didn't know this part of the code. It seems to be the right place to > do > it like you did here : > https://github.com/takari/io.takari.m2e.lifecycle/blob/master/io.takari.m2e.incrementalbuild.core/src/io/takari/m2e/incrementalbuild/core/internal/MavenComponentContributor.java > > Thus in that case what we should do is to replace for a plugin all > slf4j > artifacts in version < 1.6 it may have in dependency to use a version > 1.7.x > like our core. > > It may me think that the colorized logging may be perhaps distributed > as > an extension ? > > cheers > > > On Tue, Oct 6, 2015 at 4:23 AM, Igor Fedorenko <i...@ifedorenko.com> > wrote: > > > It is possible to use ClassRealmManagerDelegate to replace "bad" > > slf4j-related plugin dependencies with compatible "good" dependencies. > > This is what I do in my "better multithreaded logging" maven extension > > and it works quite well from what I can tell. > > > > -- > > Regards, > > Igor > > > > On Sun, Oct 4, 2015, at 10:38 AM, Arnaud Héritier wrote: > > > Hi all, > > > > > > After our exchanges this week at ApacheCon Core I wanted to have a look > > > at what avoided us to provide for exemple in 3.4 a colorised output... > > > > > > 1/ Looking at this I found several issues related to a missing export of > > > classes from SLF4J: > > > https://issues.apache.org/jira/browse/MNG-5787 > > > https://issues.apache.org/jira/browse/MNG-5842 > > > https://issues.apache.org/jira/browse/MNG-5845 > > > > > > I fixed it here: > > > > > https://github.com/apache/maven/commit/dfed29cc664f0e8f2f06278ff70d3037caf147f0 > > > > > > I hesitate to do an integration test for this. It's not really > > > difficult > > > but does it make sense to do this only for this missing slf4j export? The > > > fix is very small but the problem may be larger and highlight the fact > > > that > > > we have no control to verify that what we export is stable over the time. > > > What we should have is like a Clirr (http://clirr.sourceforge.net) > > > control > > > but which should include all the APIs we are making visible to plugins. > > > There is no simple solution to do this AFAIK. Any feedback/advice ? > > > > > > 2/ To come back to my original problem to provide colors in Maven > > > console > > > you can look at these for references: > > > https://issues.apache.org/jira/browse/MNG-3507 > > > http://www.aheritier.net/united-colors-of-maven/ > > > https://emmanuelbernard.com/blog/2015/07/27/maven-color/ > > > > > > In theory the change isn't more difficult than this commit : > > > > > https://git-wip-us.apache.org/repos/asf?p=maven.git;a=commitdiff;h=8cddea291c279130d437bcdf3337f16296558530 > > > > > > But sadly because of our usage of slf4j which has a known backward > > > incompatibility issue between 1.5 and 1.6 versions it is quickly a > > > nightmare because if a plugin has a direct or transitive dependency to a > > > slf4j additional artifact in version <=1.5 it will fail because of the > > > incompatibility like here > > > > > > [ERROR] Failed to execute goal > > > org.apache.maven.plugins:maven-checkstyle-plugin:2.15:check > > > (checkstyle-check) on project maven-checkstyle-plugin: Execution > > > checkstyle-check of goal > > > org.apache.maven.plugins:maven-checkstyle-plugin:2.15:check failed: An > > > API > > > incompatibility was encountered while executing > > > org.apache.maven.plugins:maven-checkstyle-plugin:2.15:check: > > > java.lang.NoSuchMethodError: > > > > > org.slf4j.spi.LocationAwareLogger.log(Lorg/slf4j/Marker;Ljava/lang/String;ILjava/lang/String;Ljava/lang/Throwable;)V > > > > > > [ERROR] ----------------------------------------------------- > > > > > > [ERROR] realm = > > > plugin>org.apache.maven.plugins:maven-checkstyle-plugin:2.15 > > > > > > > > > It seems to be the case for a lot of plugins which are always using maven > > > 2.x artefacts like checkstyle : > > > > > > arnaud@Arnauds-MacBook-Pro > > :~/Code/maven/trunks/plugins/maven-checkstyle-plugin > > > $ mvn dependency:tree -Dincludes=*:*slf4j*:* -Dverbose > > > > > > [INFO] Scanning for projects... > > > > > > [INFO] > > > > > > > > > [INFO] > > > ------------------------------------------------------------------------ > > > > > > [INFO] Building Apache Maven Checkstyle Plugin 2.17-SNAPSHOT > > > > > > [INFO] > > > ------------------------------------------------------------------------ > > > > > > [INFO] > > > > > > [INFO] --- maven-dependency-plugin:2.8:tree (default-cli) @ > > > maven-checkstyle-plugin --- > > > > > > [INFO] > > > > > org.apache.maven.plugins:maven-checkstyle-plugin:maven-plugin:2.17-SNAPSHOT > > > > > > [INFO] \- org.apache.maven:maven-core:jar:2.2.1:compile > > > > > > [INFO] +- > > > org.apache.maven.wagon:wagon-webdav-jackrabbit:jar:1.0-beta-6:runtime > > > > > > [INFO] | +- org.apache.jackrabbit:jackrabbit-webdav:jar:1.5.0:runtime > > > > > > [INFO] | | \- (org.slf4j:slf4j-api:jar:1.5.3:runtime - omitted for > > > conflict with 1.5.6) > > > > > > [INFO] | \- org.slf4j:slf4j-nop:jar:1.5.3:runtime > > > > > > [INFO] | \- (org.slf4j:slf4j-api:jar:1.5.3:runtime - omitted for > > > duplicate) > > > > > > [INFO] +- org.slf4j:slf4j-jdk14:jar:1.5.6:runtime > > > > > > [INFO] | \- org.slf4j:slf4j-api:jar:1.5.6:runtime > > > > > > [INFO] \- org.slf4j:jcl-over-slf4j:jar:1.5.6:runtime > > > > > > [INFO] > > > ------------------------------------------------------------------------ > > > > > > [INFO] BUILD SUCCESS > > > > > > [INFO] > > > ------------------------------------------------------------------------ > > > > > > [INFO] Total time: 2.289 s > > > > > > [INFO] Finished at: 2015-10-02T15:39:28+02:00 > > > > > > [INFO] Final Memory: 20M/336M > > > > > > [INFO] > > > ------------------------------------------------------------------------ > > > > > > A common use case for plugins or there librairies may often to add > > > slf4j > > > additional artefacts to redirect to SLF4J the output of others logging > > > librairies. > > > > > > Sadly we cannot know if the usage they have may be relevant and we have > > > no solution AFAIK to blacklist some reps or to enforce the version of a > > > library to use (or we have to expose all SLF4J artefacts from core and > > > I'm > > > afraid that it will be the source of too many others incompatibility > > > issues. > > > > > > For now I don't understand why the fact to change the logging > > > implementation enforces me to fix the slf4j conflict ( > > > > > https://git-wip-us.apache.org/repos/asf?p=maven.git;a=commitdiff;h=4c293743765b46a382371f5789e769bcac89f450 > > ). > > > It isn't required with master and I don't see how replacing slf4j-simple > > > by > > > log4j2 can increase our risk to have the slf4j backward incompatibility. > > > How is it possible that it works in master ? > > > > > > > > > Like discussed with Robert, Tibor, Hervé and Tamas for now it may be a > > > good idea for 3.4 to always provide the classical package with the > > > classical simple-logger and to provide another package/assembly including > > > the colorised version which may allow people to easily give it a try. > > > > > > Thanks for your help. > > > > > > Cheers, > > > > > > -- > > > ----- > > > Arnaud Héritier > > > http://aheritier.net > > > Mail/GTalk: aheritier AT gmail DOT com > > > Twitter/Skype : aheritier > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: dev-unsubscr...@maven.apache.org > > For additional commands, e-mail: dev-h...@maven.apache.org > > > > > > > -- > ----- > Arnaud Héritier > http://aheritier.net > Mail/GTalk: aheritier AT gmail DOT com > Twitter/Skype : aheritier --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@maven.apache.org For additional commands, e-mail: dev-h...@maven.apache.org
