grails configure log4j without rebuilding war? - grails

Question

This seems pretty strange, but when grails builds a war file it doesn't generate a log4j.properties or log4j.xml file.
Instead it has the following in WEB-INF/web.xml
web.xml:
<listener>
<listener-class>org.codehaus.groovy.grails.web.util.Log4jConfigListener</listener-class>
</listener>
and apparently "grails Log4j DSL configures logging in-memory". The problem here is - log4j isn't automatically exposed to JMX for us to dynamically change and there's no log4j file generated by grails. But Config.groovy is a compiled file.
There's got to be an easy way to manage this without rebuilding the war?
One option suggested is go through to spring and configure logging there:
resources.groovy:
beans = {
log4jConfigurer(org.springframework.beans.factory.config.MethodInvokingFactoryBean)
{
targetClass = "org.springframework.util.Log4jConfigurer"
targetMethod = "initLogging"
arguments = ["classpath:myapp/log4j.properties"]
}
}
then shift the configuration in the DSL to the configured file.
Can anyone advise the 'groovy' way to dynamically change logging configuration without rebuilding the WAR file each time. Using grails-1.3.7. Cutting the DSL out doesn't seem the right way.
Thanks

Answer 1

You may have an external config file that is searched for by your application at startup time.
You would have a MyExternalConfig.groovy file somewhere in your production environment. For example:
log4j = {
def catalinaBase = System.properties.getProperty('catalina.base')
if (!catalinaBase) catalinaBase = '.'
def logDirectory = "${catalinaBase}/logs"
appenders {
rollingFile name:"infoLog", maxFileSize:'900KB', file:"${logDirectory}/${appName}Info.log", maxBackupIndex:10, layout:pattern(conversionPattern: '%d{DATE} %p %c - %m%n'), threshold: org.apache.log4j.Level.INFO
rollingFile name:"erroLog", maxFileSize:'900KB', file:"${logDirectory}/${appName}Erro.log", maxBackupIndex:10, layout:pattern(conversionPattern: '%d{DATE} %p %c - %m%n'), threshold: org.apache.log4j.Level.ERROR
}
root {
info 'infoLog', 'erroLog'
additivity = false
}
error erroLog:"StackTrace"
error erroLog: 'org.codehaus.groovy.grails.web.servlet', // controllers
'org.codehaus.groovy.grails.web.pages', // GSP
'net.sf.ehcache.hibernate'
warn infoLog: 'org.mortbay.log'
info infoLog: "grails.app"
}
Then in your Config.groovy file, that belongs to your grails project in conf folder, you put this as the last thing of the file:
def ENV_NAME = "MY_EXTERNAL_CONFIG"
if(!grails.config.locations || !(grails.config.locations instanceof List)) {
grails.config.locations = []
}
if(System.getenv(ENV_NAME)) {
grails.config.locations << "file:" + System.getenv(ENV_NAME)
} else if(System.getProperty(ENV_NAME)) {
grails.config.locations << "file:" + System.getProperty(ENV_NAME)
} else {
println "No external configuration file defined."
}
This will look for external configurations files to add to your grails.config.locations attribute of your Config.groovy. First it looks for it as a System Environment variable (I use it this way), if it does not find, then it looks for a command line parameter (so you could add it when you start your tomcat app, as a parameter to startup.sh).
To configure your system environment variabble, just do this before starting tomcat:
MY_EXTERNAL_CONFIG="/home/tomcat/configs/MyExternalConfig.groovy"
export MY_EXTERNAL_CONFIG
--- start tomcat here ---
That's it.