On Aug 19, 2009, at 2:15 PM, Ceki Gulcu wrote:
Ralph Goers wrote:
* The provision of the Locale should be an orthogonal concept to
the logging of messages and the creation of the Logger. This
should be handled via the MDC.
"could be handled via the MDC". There are other ways to do it but
that is probably the simplest.
Pushing the locale in every thread will not suite everyone.
Probably not. In those cases the method you described before using the
LoggerContext would probably work.
But it depends on the use case. In a lot of systems the operations
staff will want all the log messages in a single language of the
locale where the software is running and the locale of the end user
will be irrelevant. In cases like event logging it may be that the
event logs are viewed by customer service reps speaking in multiple
languages. In that case the locale of the person viewing the log is
important (which may be days or months after the log entry was
recorded). The least critical scenario, in my opinion, is where the
log entry will be viewed by the end user. IMO this isn't the best use
of a logging system.
OTOH, in my case we would still put the locale of the end user in the
MDC simply because other GUI components will want that information.
IMO there are still a few questions to answer:
* Takeshi original design allowed you to use Enums as keys for
messages. I'm personally not sure about this, I'm not really sure
what benefits it offers over Strings as keys
Enums are usually associated with an integer "value" and a String
description. The only value is that you might be able to get some
optimization by using the integer value of the enum in some cases.
I don't know that it is worth the effort to support it.
Unless enums have some other advantage that we did not think of.
Takeshi can you describe the advantages of enums that you see?
* How does a framework provide translated messages [1] to i8ln
layer? Can we also use the MDC here to push them in, and have the
appender read them?
I'm not sure I understand the question. The framework will provide
a method like:
public String getMessage(String key, Object[] params);
However the messages are stored is hidden behind the implementation
of that interface. Something has to call getMessage(). Potential
places are a) the application before calling SLF4J b) SLF4J before
calling a logging implementation, c) In the logging implementation
- such as in the Appender.
Bingo. a), b) or c) is the question. There is also a) and b)
combined. See my previous message.
Again, that depends. For example, Lillith (http://freshmeat.net/projects/lilith-viewer
) is an event viewer for Logback. It would be very appropriate for
it to do this. Likewise with Apache Chainsaw for Log4j. Doing the
L10N further up the chain limits the flexibility these tools can
provide. Sometimes that is desirable, but my recommendation is to
always start from as far back as possible and move up the stack
only as far as you have to.
If SLF4J or logback provided a reasonable solution, it would help
developers in solving the logging i18n issue by the mere fact of
offering and thus blessing a solution. It could only do harm if the
offered solution was particularly stupid or bad. Moreover, the
solution provided in slf4j or logback (or in both in part) could lay
the foundation of a better solution imagined by one of our users.
+1. That is why we would want to consider several use cases. I don't
think there is a one size fits all solution.
Ralph
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