Hi Ralph,
I have something related to this improvement idea.
I have thought it might be a bit more useful and flexible to allow default
value in the variable expression itself.
For example, ${var1:-defvalue1}, ${ctx:request_id:-defvalue2}, etc.
This generic feature has been included in StrSubstitutor of commons-lang3 with
the following issue:
- https://issues.apache.org/jira/browse/LANG-893
I understand Oliver's patch should work more efficiently for map pattern
converters, but the goodness of the feature with LANG-893 is we can use it more
widely whenever used in look ups.
I know StrSubstitutor in log4j2 added more operations to deal with LogEvent
argument, so I can create a patch to include the feature of LANG-893 if it is
useful for others.
Also, Oliver's patch won't conflict with this patch.
What do you think?
Kind regards,
Woonsan
> On Tuesday, October 1, 2013 9:21 AM, Ralph Goers <[email protected]> wrote:
> > Patches are always welcome!
>
> Ralph
>
> On Oct 1, 2013, at 1:13 AM, Oliver Flege <[email protected]> wrote:
>
>>> $${mdc:request_id} in a pattern should cause the request_id to be
> evaluated on every event.
>>
>> thanks a lot, $${ctx:request_id} seems to do the trick
>>
>> however, the computation of the default value is quite complex as it always
> involves
>> a variable substitution, and I cannot use conversion specifiers with $$ as
> I can with %X
>>
>> Would you consider accepting a patch that adds support for slf4j-like
> default values
>> in %X{key} and %K{key}, s.th. like %X{key:-defaultValue} ?
>>
>> Regards,
>> Oliver
>>
>>
>>
>>>
>>>> On Sep 30, 2013, at 8:04 AM, Oliver Flege <[email protected]>
> wrote:
>>>>
>>>> ok, this works for ${...} expressions in the configuration,
> but I don't see how it would
>>>> apply to pattern evaluation. To simplify and rephrase my original
> question:
>>>>
>>>> Given a pattern layout with a pattern like: %X{REQUEST_ID}
>>>>
>>>> is it possible to define a default value that will be printed
>>>> if the thread never executed
> ThreadContext.put("REQUEST_ID", "XYZ")?
>>>>
>>>> I tried ${mdc:REQUEST_ID} + a Property REQUEST_ID, but that
>>>> will only be evaluated when the configuration is parsed.
>>>>
>>>> Oliver
>>>>
>>>>> Yes, it supports default values. Specify them as properties at
> the beginning of your configuration. Then when you specify something like
> ${sys:foo} if foo is not defined as a system property the default value
> will be used,
>>>>>
>>>>> Ralph
>>>>>
>>>>>> On Sep 30, 2013, at 3:30 AM, Oliver Flege
> <[email protected]> wrote:
>>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> I am considering to switch from slf4j/logback to log4j2;
>>>>>>
>>>>>> in slf4j/logback, I can specify a default value for a
> missing mdc entry
>>>>>> like this:
>>>>>>
>>>>>> <pattern>%d{HH:mm:ss} %X{FOO:--} %c{0}
> - %m%n</pattern>
>>>>>>
>>>>>> which would print "-" if mdc.get("FOO")
> is null (the ":-" separates
>>>>>> the key and the default value).
>>>>>>
>>>>>> Having a defined number of tokens/fields at the beginning
> of the log message
>>>>>> makes it easier to process it with awk/cut etc.
>>>>>>
>>>>>>
>>>>>> Does log4j support default values? - I could not find any
> hint in the documentation
>>>>>>
>>>>>>
>>>>>>
>>>>>> Regards,
>>>>>> Oliver
>>>>>>
>>>>>>
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>>>>>
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>>>>
>>>> --
>>>> Oliver Flege
>>>> Senior Software Engineer | vwd group
>>>>
>>>> vwd Vereinigte Wirtschaftsdienste AG
>>>> Stiftsplatz 6/7 | 67655 Kaiserslautern
>>>> Telefon: +49 631 3649-0 | Telefax: +49 631 3649-109
>>>> [email protected] | www.vwd.com
>>>> ______________________________________________________________
>>>>
>>>> vwd Vereinigte Wirtschaftsdienste AG
>>>> Sitz der Gesellschaft: Tilsiter Straße 1 | 60487 Frankfurt am Main
>>>> Handelsregister: AG Frankfurt am Main HRB 81011
>>>> Vorstand: Dr. Ralf Kauther
>>>> Vorsitzender des Aufsichtsrates: Dr. Thorsten Dippel
>
>>>> ____________________________________________________________
>>>>
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>>
>>
>> --
>> Oliver Flege
>> Senior Software Engineer | vwd group
>>
>> vwd Vereinigte Wirtschaftsdienste AG
>> Stiftsplatz 6/7 | 67655 Kaiserslautern
>> Telefon: +49 631 3649-0 | Telefax: +49 631 3649-109
>> [email protected] | www.vwd.com
>> ______________________________________________________________
>>
>> vwd Vereinigte Wirtschaftsdienste AG
>> Sitz der Gesellschaft: Tilsiter Straße 1 | 60487 Frankfurt am Main
>> Handelsregister: AG Frankfurt am Main HRB 81011
>> Vorstand: Dr. Ralf Kauther
>> Vorsitzender des Aufsichtsrates: Dr. Thorsten Dippel
>> ____________________________________________________________
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: [email protected]
>> For additional commands, e-mail: [email protected]
>>
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