log4cplus-devel

[Log4cplus-devel] Header line for file appenders

[Steve H. <sha...@mi...>]

Hello all,

I have recently run into a situation in which it would have been really convenient if the file appenders had some way to add a header line to the top of each file.  I don't mind doing the coding for this, but first wanted to throw the idea out there to see if someone else may have a better idea for implementation.

My plan was to simply add an attribute to the file appenders named something like "FileHeader" which would contain a string.  That string would be inserted as the first line in each file.  For example:

log4cplus.temperatureLogger=DEBUG, A2
log4cplus.appender.A2=log4cplus::DailyRollingFileAppender
log4cplus.appender.A2.File=log/temperature
log4cplus.appender.A2.layout=log4cplus::PatternLayout
log4cplus.appender.A2.Schedule=DAILY
log4cplus.appender.A2.MaxBackupIndex=2
log4cplus.appender.A2.FileHeader=Date Temperature1 Setpoint1 Temperature2 Setpoint2%n
log4cplus.appender.A2.layout.ConversionPattern=%D{%Y-%m-%d %H:%M:%S.%q}  %m%n

Or should this be implemented in the layout?


Thoughts?

Regards,

Steven Hartmann

Re: [Log4cplus-devel] Header line for file appenders

[Václav Z. <vha...@gm...>]

On 28 January 2014 23:13, Steve Hartmann wrote:
> Hello all,
>
> I have recently run into a situation in which it would have been really
> convenient if the file appenders had some way to add a header line to the
> top of each file.

This is an interesting idea. I am not opposed to adding this feature
to log4cplus.

> I don't mind doing the coding for this, but first wanted
> to throw the idea out there to see if someone else may have a better idea
> for implementation.
>
> My plan was to simply add an attribute to the file appenders named something
> like "FileHeader" which would contain a string.  That string would be
> inserted as the first line in each file.  For example:
>
> log4cplus.temperatureLogger=DEBUG, A2
> log4cplus.appender.A2=log4cplus::DailyRollingFileAppender
> log4cplus.appender.A2.File=log/temperature
> log4cplus.appender.A2.layout=log4cplus::PatternLayout
> log4cplus.appender.A2.Schedule=DAILY
> log4cplus.appender.A2.MaxBackupIndex=2
> log4cplus.appender.A2.FileHeader=Date Temperature1 Setpoint1 Temperature2
> Setpoint2%n
> log4cplus.appender.A2.layout.ConversionPattern=%D{%Y-%m-%d %H:%M:%S.%q}
> %m%n
>
> Or should this be implemented in the layout?

It seems to me that layout would be a better place for this.

Is there a prior art for this feature in log4j (or any other Java
logging library) or log4net, etc.? We could copy their design
decisions / interfaces.

Re: [Log4cplus-devel] Header line for file appenders

[Steve H. <sha...@mi...>]

On 1/29/14 3:38 AM, "Václav Zeman" <vha...@gm...> wrote:

>It seems to me that layout would be a better place for this.
>
>Is there a prior art for this feature in log4j (or any other Java
>logging library) or log4net, etc.? We could copy their design
>decisions / interfaces.
>

With log4j, you have to extend the layout.  Here is a link to an article
on how to use it:  
http://www.coderanch.com/t/535099/oa/Inserting-Header-Text-Log-file

Personally, I would like to just have it built in as a property - what do
you think?

Re: [Log4cplus-devel] Header line for file appenders

[Václav Z. <vha...@gm...>]

On 01/29/2014 07:20 PM, Steve Hartmann wrote:
> 
> 
> On 1/29/14 3:38 AM, "Václav Zeman" <vha...@gm...> wrote:
> 
>> It seems to me that layout would be a better place for this.
>>
>> Is there a prior art for this feature in log4j (or any other Java
>> logging library) or log4net, etc.? We could copy their design
>> decisions / interfaces.
>>
> 
> With log4j, you have to extend the layout.  Here is a link to an article
> on how to use it:  
> http://www.coderanch.com/t/535099/oa/Inserting-Header-Text-Log-file
> 
> Personally, I would like to just have it built in as a property - what do
> you think?
> 

Yeah, I do not think that having to derive own layout is the way to go.
It should be built-in. I am not sure if it should be in PatternLayout
(and TTCCLayout) only or if it should be part of the base Layout class;
Adding the header information to a new base class, that would be between
Layout and PatternLayout does not sound wrong to me. I can imagine a
layout without a need for a header (e.g., XMLLayout). But adding it to
the base class would be a lot less intrusive.

(...)

OK, my suggestion is to keep Layout, SimpleLayout and TTCCLayout as they
are, no header. Add a new base class, say, LayoutHeader with virtual
tstring getHeader() const = 0 member function and inherit from this new
base class and implement the pure virtual member function in
PatternLayout. Use dynamic_cast<LayoutHeader *> to test for header
availability in appenders where it makes any sense.

-- 
VZ