[logback-dev] Question about logback

[ceki]

On 07.06.2012 10:24, stephen.t.chan at asia.bnpparibas.com wrote:
> Hi all,
>
 >
 > I am running tomcat6 as http server and specify jdbc connection(with
 > login credential) in context.xml.  Besides, I have defined to use
 > DBAppender in logback.xml to write log to database.  My question is,
 > instead of directly write the login credential in the logback.xml
 > file, how to use property substitution to retrieve the credential from
 > tomcat context.xml?
>
> for example,
>
> <appendername=/"DB"/class=/"com.eqd.iprice.appender.DBAppender"/>
> <connectionSourceclass=/"ch.qos.logback.core.db.DriverManagerConnectionSource"/>
>
> <dataSourceclass=/"javax.sql.DataSource"/>
> <driverClass>${driverClass}</driverClass>
> <url>${url}</url>
> <user>${username}</user>
> <password>${password}</password>
> </dataSource>
> </connectionSource>
> </appender>
>
> Those ${XXXX} are retrieved from tomcat context.xml .
>
> Thanks.
>
> Stephen

Hi Stephen,

Here are a couple of approaches you could try.

Approach 1)

If there is a programmatic way to access the variables defined in
context.xml, then you could easily write a custom property definer
[1]. As long as you can access variables defined in context.xml, and
that's a relatively big if, writing a custom property definer should
be a piece of cake.

Approach 2)

If it is not possible to access the variables defined in context.xml,
you can redefine them in web.xml as JNDI variables. Logback can obtain
variables from JNDI.

This approach has the inconvenience of forcing you to define variables
twice, once in content.xml and once in web.xml.

Approach 3)

The best approach in my opinion is to obtain a connection source from
JNDI. The connection source is defined in Tomcat and logback retrieves
and uses it.  See JNDIConnectionSource in DBAppender documentation
[3].

Please keep us posted on your progress.

Cheers,

[1] http://logback.qos.ch/manual/configuration.html#definingPropsOnTheFly
[2] http://logback.qos.ch/manual/configuration.html#insertFromJNDI
[3] http://logback.qos.ch/manual/appenders.html#DBAppender

-- 
Ceki
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