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From Vlad Rozov <v.ro...@datatorrent.com>
Subject Re: Adding new log4j appender to Apex core
Date Thu, 24 Nov 2016 17:53:04 GMT
David,

Yes, I understand that the functionality will only be available in case 
of the predefined log file appender. IMO, such assumption is too 
restrictive and it does not look that the default configuration will 
cover majority of use cases. Also, JIRA talks about providing offset in 
the log file. Does this mean that events can only be consumed by a tool? 
For human line number will be more useful.

Thank you,

Vlad

On 11/23/16 22:27, David Yan wrote:
> Vlad,
>
> The feature only works *if the log file name at error does not change later*
> .
>
> In this case, Priyanka proposes a default appender that the user can use
> that has this behavior while log rotation is still supported.
>
> If the user has a custom log appender, the feature can still work if it
> satisfies the above requirement. Otherwise, there is no way for this
> feature to work.
>
> We can support a configuration option to force the inclusion of log
> location and offset in the error STRAM event even if the Apex appender is
> not used, if the user knows that they are using a custom appender that
> satisfies the requirement.
>
> David
>
> On Wed, Nov 23, 2016 at 8:47 PM, Vlad Rozov <v.rozov@datatorrent.com> wrote:
>
>> Additionally, I think that it is necessary to re-evaluate the
>> requirements. Custom logging is quite common and many enterprises/Devops
>> have own preferences/policy for log rotation and logging format. I saw
>> instances when logging was redirected to stdout. By enforcing specific
>> rotation policy or log format, the feature is more likely not to be used.
>>
>> Thank you,
>>
>> Vlad
>>
>>
>> On 11/23/16 14:21, Vlad Rozov wrote:
>>
>>> Both approaches look quite "hacky" to me.
>>>
>>> Thank you,
>>>
>>> Vlad
>>>
>>> On 11/23/16 00:01, Mohit Jotwani wrote:
>>>
>>>> +1 - Approach 2
>>>>
>>>> Regards,
>>>> Mohit
>>>>
>>>> On Wed, Nov 23, 2016 at 12:35 PM, AJAY GUPTA <ajaygit158@gmail.com>
>>>> wrote:
>>>>
>>>> +1 for approach 2.
>>>>>
>>>>> Regards,
>>>>> Ajay
>>>>>
>>>>> On Wed, Nov 23, 2016 at 12:16 PM, David Yan <david@datatorrent.com>
>>>>> wrote:
>>>>>
>>>>> The goal of this log4j appender is to provide a log offset and the fixed
>>>>>> name of the container log file (instead of apex.log becoming apex.log.1
>>>>>>
>>>>> and
>>>>>
>>>>>> then apex.log.2, etc due to rotation) as part of an error STRAM event
>>>>>> so
>>>>>> users can easily locate the log entries around the error.
>>>>>>
>>>>>> The user can override the appender, but in that case, the engine
>>>>>> detects
>>>>>> that and will not include the log location as part of the STRAM event.
>>>>>>
>>>>>> David
>>>>>>
>>>>>> On Tue, Nov 22, 2016 at 7:10 PM, Priyanka Gugale <
>>>>>>
>>>>> priyanka@datatorrent.com
>>>>>
>>>>>> wrote:
>>>>>>
>>>>>> Hi,
>>>>>>> Thomas,
>>>>>>> Yes log4j is ultimately owned by user, and they should be able
to
>>>>>>>
>>>>>> override
>>>>>>
>>>>>>> it. What I am trying to do is provide a default behavior for
Apex. In
>>>>>>>
>>>>>> case
>>>>>>
>>>>>>> user isn't using any logger of their own we should use this new
>>>>>>>
>>>>>> appender
>>>>>> of
>>>>>>
>>>>>>> Apex rather than using standard log4j appender as per hadoop
config.
>>>>>>>
>>>>>>> Sanjay,
>>>>>>> Archetype is the good place to put this and I will add it there,
but
>>>>>>>
>>>>>> many
>>>>>> time people won't use it. So I wanted to keep it at ~/.dt as well.
Is
>>>>>> there
>>>>>>
>>>>>>> any other default config folder for Apex?
>>>>>>>
>>>>>>> Also I am not relying on anything. If we fail to find config
in app
>>>>>>> jar
>>>>>>>
>>>>>> or
>>>>>>
>>>>>>> ~/.dt we are going to skip usage of this new appender.
>>>>>>>
>>>>>>> -Priyanka
>>>>>>>
>>>>>>> On Wed, Nov 23, 2016 at 5:58 AM, Sanjay Pujare <
>>>>>>> sanjay@datatorrent.com
>>>>>>> wrote:
>>>>>>>
>>>>>>> The only way to “enforce” this new appender is to update
the
>>>>>>> archetypes
>>>>>> (apex-app-archetype and apex-conf-archetype under apex-core/ )  to
>>>>>>> use
>>>>>> the
>>>>>>>> new ones as default. But there does not seem to be a way
to enforce
>>>>>>>>
>>>>>>> this
>>>>>>> for anyone not using the archetypes.
>>>>>>>> I agree with not relying on ~/.dt in apex-core.
>>>>>>>>
>>>>>>>> On 11/22/16, 1:08 PM, "Thomas Weise" <thw@apache.org>
wrote:
>>>>>>>>
>>>>>>>>       The log4j configuration is ultimately owned by the
user, so how
>>>>>>>>
>>>>>>> do
>>>>>> you
>>>>>>>> want
>>>>>>>>       to enforce a custom appender?
>>>>>>>>
>>>>>>>>       I don't think that this should rely on anything in
~/.dt either
>>>>>>>>
>>>>>>>>       Thomas
>>>>>>>>
>>>>>>>>       On Tue, Nov 22, 2016 at 10:00 AM, Priyanka Gugale <
>>>>>>>> priyanka@datatorrent.com>
>>>>>>>>       wrote:
>>>>>>>>
>>>>>>>>       > Hi,
>>>>>>>>       >
>>>>>>>>       > I am working on APEXCORE-563
>>>>>>>>       > <https://issues.apache.org/jira/browse/APEXCORE-563>
>>>>>>>>       > As per this Jira we should put log file name in
>>>>>>>>
>>>>>>> container/operator
>>>>>>> events.
>>>>>>>>       > The problem is current RollingFileAppender keeps
renaming
>>>>>>>> files
>>>>>>>>
>>>>>>> from
>>>>>>>
>>>>>>>> 1 to 2
>>>>>>>>       > to ... n as files reach maximum allowed file size.
Because of
>>>>>>>> constant
>>>>>>>>       > renaming of files we can't put a fixed file name
in stram
>>>>>>>>
>>>>>>> event.
>>>>>>       >
>>>>>>>>       > To overcome this I would like to add a new log4j
appender to
>>>>>>>> ApexCore.
>>>>>>>>       > There are two ways I can implement this:
>>>>>>>>       > 1. Have Daily rolling file appender. The current
file will be
>>>>>>>> recognized
>>>>>>>>       > based on timestamp in file name. Also to control
max file
>>>>>>>> size,
>>>>>>>>
>>>>>>> we
>>>>>>> need to
>>>>>>>>       > keep rolling files based on size as well.
>>>>>>>>       > 2. Have Rolling File Appender but do not rename
files. When
>>>>>>>> max
>>>>>>>>
>>>>>>> file
>>>>>>>
>>>>>>>> size
>>>>>>>>       > is reached create new file with next number e.g.
crate log
>>>>>>>> file
>>>>>>>> dt.log.2
>>>>>>>>       > after dt.log.1 is full. Also to recognize the
latest file keep
>>>>>>>>
>>>>>>> the
>>>>>>> softlink
>>>>>>>>       > named dt.log pointing to current log file.
>>>>>>>>       >
>>>>>>>>       > I would prefer to implement approach 2. Please
provide your
>>>>>>>>       > comments/feedback if you feel otherwise.
>>>>>>>>       >
>>>>>>>>       > Also to use this new appender we need to use our
custom
>>>>>>>> log4j.properties
>>>>>>>>       > file instead of one present in hadoop conf. For
that we need
>>>>>>>> to
>>>>>>>>
>>>>>>> set
>>>>>>> jvm
>>>>>>>>       > option -Dlog4j.configuration. I am planning to
update file
>>>>>>>> dt-site.xml in
>>>>>>>>       > folder ~/.dt  and default properties file available
in apex
>>>>>>>> archetype to
>>>>>>>>       > set jvm options as follows:
>>>>>>>>       >  <property>
>>>>>>>>       > <name>dt.attr.CONTAINER_JVM_OPTIONS</name>
>>>>>>>>       > <value>-Dlog4j.configuration=log4j.props</value>
>>>>>>>>       >  </property>
>>>>>>>>       >
>>>>>>>>       > And I will copy log4j.props file in ~/.dt folder
as well as
>>>>>>>>       > apex-archetypes.
>>>>>>>>       >
>>>>>>>>       > Lastly if someone still miss this new log4j properties
file or
>>>>>>>>
>>>>>>> jvm
>>>>>>> option
>>>>>>>>       > to set -Dlog4j.configuration we will not put log
file name in
>>>>>>>>
>>>>>>> event
>>>>>>> raised
>>>>>>>>       > by container or operator.
>>>>>>>>       >
>>>>>>>>       > Please provide your feedback on this approach.
>>>>>>>>       >
>>>>>>>>       > -Priyanka
>>>>>>>>       >
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>


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