On Tue, Jan 11, 2022 at 8:20 AM 张铎(Duo Zhang) <[email protected]> wrote:

> So we could open an issue for this feature then? As we have already started
> to discuss the implementation :)
>

Yes, that sounds like a good idea. Feel free to go ahead :-)

Gary


>
> Thanks~
>
> Volkan Yazıcı <[email protected]> 于2022年1月11日周二 19:42写道:
>
> > Giving it a one more try:
> >
> > <CompoundProperty>
> >    <Source>${sys:hadoop.root.logger}</Source>
> >    <Split delimiter="\s+" trim="true" blanksExcluded="true">
> >        <item index="0">hadoop.root.logger.level</item>
> >        <slice startIndex="1">hadoop.root.logger.appender</slice>
> >    </Split>
> > </CompoundProperty>
> >
> > On Mon, Jan 10, 2022 at 3:54 PM Ralph Goers <[email protected]>
> > wrote:
> >
> > > Yeah, that syntax is better although it doesn’t solve the multiple
> > > appender refs case either.
> > >
> > > LoggerConfig accepts a List<AppenderRef> so it would seem that if we
> > > modify LoggerConfig
> > > to add another attribute that is a string that creates an AppenderRef
> for
> > > each item then
> > > one could do
> > >
> > > <Logger name=“xyzzy” level=“INFO” appenderRefNames=“a, b, c”/>
> > >
> > >
> > > Ralph
> > >
> > > > On Jan 10, 2022, at 5:04 AM, Volkan Yazıcı <[email protected]> wrote:
> > > >
> > > > I am curious if shall we adopt a more generic approach to extraction:
> > > >
> > > > <CompoundProperty>
> > > >   <Source>${sys:hadoop.root.logger}</Source>
> > > >   <Targets pattern="^(.+)\s*,\s(.+)$">
> > > >       <Target>hadoop.root.logger.level</Target>
> > > >       <Target>hadoop.root.logger.appender</Target>
> > > >   </Targets>
> > > > </CompoundProperty>
> > > >
> > > > On Mon, Jan 10, 2022 at 5:53 AM Ralph Goers <
> > [email protected]>
> > > > wrote:
> > > >
> > > >> OK, I had a suspicion the reason for needing this was something like
> > > that.
> > > >>
> > > >> The syntax you propose below would require modifying PropertiesUtil,
> > the
> > > >> Property
> > > >> plugin and StrSubstitutor to support arrays. I don’t think I’d want
> to
> > > go
> > > >> down that path.
> > > >> StrSubstitutor is already complicated and the idea of enhancing it
> to
> > > >> support stuff like
> > > >> this doesn’t excite me.
> > > >>
> > > >> I think we’d be better off creating a new plugin for this. Something
> > > like:
> > > >>
> > > >> <CompoundProperty name=“hadoop.root.logger.level” split=“,”
> > > >> index=“0”>${sys:hadoop.root.logger}</CompoundProperty>
> > > >> <CompoundProperty name=“hadoop.root.logger.appender” split=“,”
> > > >> index=“1”>${sys:hadoop.root.logger}</CompoundProperty>
> > > >>
> > > >> The only problem here is if you want to provide more than one
> appender
> > > >> this won’t
> > > >> work well. But I am sure we could enhance AppenderRef to accept a
> list
> > > of
> > > >> appenders.
> > > >>
> > > >> Ralph
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>> On Jan 9, 2022, at 5:29 PM, 张铎(Duo Zhang) <[email protected]>
> > > wrote:
> > > >>>
> > > >>> Thank you for the reply.
> > > >>>
> > > >>> And yes, it is not only for the root logger, we have tons of
> > different
> > > >>> loggers in hadoop, as hadoop is constructed with several different
> > > >> projects
> > > >>> actually, and they are developed by different groups of people...
> > > >>>
> > > >>> And on splitting the config in shell, actually this is exactly
> what I
> > > >> have
> > > >>> done in HBase
> > > >>>
> > > >>> See
> > > >>>
> > > >>
> > >
> >
> https://github.com/apache/hbase/blob/3ec3df5887e9271f7e75779eafe2439012cfb2c3/bin/hbase#L829
> > > >>>
> > > >>> And also
> > > >>>
> > > >>
> > >
> >
> https://github.com/apache/hbase/blob/3ec3df5887e9271f7e75779eafe2439012cfb2c3/bin/hbase.cmd#L336
> > > >>>
> > > >>> For HBase maybe it is acceptable but hadoop is another story.
> > > >>> Hadoop is widely used almost in every bigdata platform. Among the
> > > >>> companies I've worked with, they all have their own hadoop
> deployment
> > > >>> systems which have modified version of start up scripts...
> > > >>>
> > > >>> I can imagine that if we do the same trick in HBase, then people
> will
> > > ask
> > > >>> again and again on the mailing list why passing
> -Dhadoop.root.logger
> > > does
> > > >>> not work, as well as other options like -Dyarn.root.logger,
> > > >>> -Dhadoop.security.logger, etc...
> > > >>>
> > > >>> So it will be good if we can support configure level and appenders
> in
> > > one
> > > >>> property.
> > > >>>
> > > >>> Or maybe another way is to enhance the ability in the Properties
> > > section,
> > > >>> so we can split one property into two properties, something like
> > > >>>
> > > >>> <Properties>
> > > >>> <Property name="hadoop.root.logger"
> > > >>> type="array">${sys:hadoop.root.logger:-INFO,Console}</Property>
> > > >>> <Property
> > > >>> name="hadoop.root.logger.level">${hadoop.root.logger[0]}</Property>
> > > >>> <Property name="hadoop.root.logger.appender">
> > ${hadoop.root.logger[1]}
> > > >>> </Property>
> > > >>> <Properties>
> > > >>>
> > > >>> Notice that since we could add multiple appenders here, maybe we
> need
> > > to
> > > >>> support something like ${hadoop.root.logger[1:] to combine all the
> > > >>> appenders...
> > > >>> This could also solve the problem as people could still pass
> > > >>> -Dhadoop.root.logger.
> > > >>>
> > > >>> But I'm not sure if adding the ability to split a string in
> > > configuation
> > > >>> could introduce new possible security concerns...
> > > >>>
> > > >>> Thanks.
> > > >>>
> > > >>> Ralph Goers <[email protected]> 于2022年1月10日周一 07:14写道:
> > > >>>
> > > >>>> We already support this with two variables. But if they only want
> to
> > > >> pass
> > > >>>> one then we have two options:
> > > >>>> 1. Modify PropertiesConfiguration to support a new element that
> > > allows a
> > > >>>> Level and AppenderRef which then gets split internally.
> > > >>>> 2. Create a Lookup that extracts the relevant portion of the data.
> > > >>>>
> > > >>>> Ralph
> > > >>>>
> > > >>>>> On Jan 9, 2022, at 3:08 PM, Gary Gregory <[email protected]
> >
> > > >> wrote:
> > > >>>>>
> > > >>>>> I think it is reasonable to say we can support this through 2
> > instead
> > > >> of
> > > >>>> 1
> > > >>>>> variable.
> > > >>>>>
> > > >>>>> Duo?
> > > >>>>>
> > > >>>>> Gary
> > > >>>>>
> > > >>>>> On Sun, Jan 9, 2022, 16:24 Ralph Goers <
> [email protected]
> > >
> > > >>>> wrote:
> > > >>>>>
> > > >>>>>> I’m looking at this and have a couple of concerns. The script
> has
> > > >>>>>>
> > > >>>>>>
> > > >>>>>>
> > HADOOP_ROOT_LOGGER=${HADOOP_ROOT_LOGGER:-${HADOOP_LOGLEVEL},console}
> > > >>>>>>
> > > >>>>>>
> > > >>>>
> > > >>
> > >
> >
> HADOOP_DAEMON_ROOT_LOGGER=${HADOOP_DAEMON_ROOT_LOGGER:-${HADOOP_LOGLEVEL},RFA}
> > > >>>>>>
> > HADOOP_SECURITY_LOGGER=${HADOOP_SECURITY_LOGGER:-INFO,NullAppender}
> > > >>>>>>
> > > >>>>>> So it seems you need this for more than just the root logger.
> > > >>>>>>
> > > >>>>>> Second, you are asking us to accept “level, appender”  as the
> > value
> > > >> and
> > > >>>>>> under the covers split the
> > > >>>>>> value and assign the level to the level attribute and the
> appender
> > > >> name
> > > >>>> to
> > > >>>>>> the AppenderRef.
> > > >>>>>>
> > > >>>>>> While this certainly can be done it seems like it would be just
> as
> > > >> easy
> > > >>>> to
> > > >>>>>> do the split in the script
> > > >>>>>> and create two different variables for the logging configuration
> > to
> > > >> pick
> > > >>>>>> up.  Is there a reason that
> > > >>>>>> you can’t do this - for example perhaps users have hacked your
> > > scripts
> > > >>>> and
> > > >>>>>> now you can’t
> > > >>>>>> change them without breaking them? If so, was this “supported”?
> > > >>>>>>
> > > >>>>>> Ralph
> > > >>>>>>
> > > >>>>>>
> > > >>>>>>
> > > >>>>>>> On Jan 9, 2022, at 8:01 AM, 张铎(Duo Zhang) <
> [email protected]
> > >
> > > >>>> wrote:
> > > >>>>>>>
> > > >>>>>>> I brought this up in the incubator mailing list, and was
> > suggested
> > > to
> > > >>>>>>> report directly to the log4j community.
> > > >>>>>>>
> > > >>>>>>> https://issues.apache.org/jira/browse/HADOOP-16206
> > > >>>>>>>
> > > >>>>>>> In hadoop we started to try migrating to log4j2 long ago, but
> it
> > is
> > > >> not
> > > >>>>>>> easy. For now, one of the most blocker issues is the lack of
> > > support
> > > >> of
> > > >>>>>>> 'log4j.rootLogger=INFO,Console' grammar. Notice that we do not
> > want
> > > >> to
> > > >>>>>> stay
> > > >>>>>>> on the bridge api, we want to fully migrate to log4j2 finally,
> so
> > > >>>>>>> supporting the above grammar in log4j1 bridge is not enough.
> > > >>>>>>>
> > > >>>>>>> This is the main log4j configuration file for hadoop
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>
> > > >>>>
> > > >>
> > >
> >
> https://github.com/apache/hadoop/blob/trunk/hadoop-common-project/hadoop-common/src/main/conf/log4j.properties
> > > >>>>>>>
> > > >>>>>>> We have this in the file
> > > >>>>>>>
> > > >>>>>>> # Define the root logger to the system property
> > > "hadoop.root.logger".
> > > >>>>>>>> log4j.rootLogger=${hadoop.root.logger}
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>> So our users could simply pass -Dhadoop.root.logger to control
> > the
> > > >>>> level
> > > >>>>>>> and appender.
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>
> > > >>>>
> > > >>
> > >
> >
> https://github.com/apache/hadoop/blob/39efbc6b6fe53abed15f5639edcbaaa2a9dda6d2/hadoop-common-project/hadoop-common/src/main/bin/hadoop-functions.sh#L904
> > > >>>>>>>
> > > >>>>>>> Here we use an environment variable in our start up scripts.
> And
> > I
> > > >>>>>> believe
> > > >>>>>>> there are lots of other hadoop deployment systems which will
> have
> > > >> their
> > > >>>>>> own
> > > >>>>>>> start scripts.
> > > >>>>>>>
> > > >>>>>>> So in general, it is just impossible for us to drop the
> > > >>>>>>> -Dhadoop.root.logger way of configuring our logging system.
> > > >>>>>>>
> > > >>>>>>> So here I want to ask if it is possible for log4j2 to still
> > support
> > > >> the
> > > >>>>>>> 'log4j.rootLogger=INFO,Console' grammar. I'm not saying you
> must
> > > add
> > > >> it
> > > >>>>>>> back with no change, we just need a way to configure the level
> > and
> > > >>>>>> appeners
> > > >>>>>>> at once, so something like
> > > >>>>>>> 'log4j2.rootLogger.levelAndAppender=INFO,Console' is also OK.
> > > >>>>>>>
> > > >>>>>>> Thanks.
> > > >>>>>>
> > > >>>>>>
> > > >>>>
> > > >>>>
> > > >>
> > > >>
> > >
> > >
> >
>

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