Logging in Grails: reloadable external configuration with Log4j2

Question

I'm trying to configure Grails so as to use external Log4j2 configuration files separating production and development mode. It should listen for configuration changes and refresh it after some period of time. For Grails 2.x, it can be done by registering Log4jConfigurer beans like this:

switch (Environment.current) {
   case Environment.PRODUCTION:
      log4jConfigurer(MethodInvokingFactoryBean) {
         targetClass = "org.springframework.util.Log4jConfigurer"
         targetMethod = "initLogging"
         arguments = ["classpath:ogc-log4j.xml", 30000]
      } 

   case Environment.DEVELOPMENT:
     log4jConfigurer(MethodInvokingFactoryBean) {
        targetClass = "org.springframework.util.Log4jConfigurer"
        targetMethod = "initLogging"
        arguments = ["classpath:log4j-dev.xml", 30000]
     }
}

For some reasons, this approach doesn't work in Grails 3.x. How can I do this in Grails 3.3.3 or in Spring Boot (I guess it should work because Grails 3.x is based on Spring Boot)?

Do you want to reload the external configuration of Log4j2. – Akhil Surapuram Apr 18 '19 at 12:44 — Akhil Surapuram, Apr 18 '19 at 12:44

score 1 · Answer 1 · answered Apr 18 '19 at 12:58

1

From 3.3.3 of grails

Instead of having it in Java code. Environment configuration has moved to the YML configuration file.

we can pass different values to different environments and change configuration of log4j

refer to the documentation

documentaion for Enviroment configuration

answered Apr 18 '19 at 12:58

Akhil Surapuram

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Have you tested it? Because this doesn't work with log4j either. See https://github.com/grails/grails-core/issues/11303 – Taras Kohut Apr 18 '19 at 13:11
you need to pass different string values to arguments value of l log4jConfigurer – Akhil Surapuram Apr 18 '19 at 13:16
Okay, it seems like their current bug. I have answered by referring their docs – Akhil Surapuram Apr 18 '19 at 13:23

Tung · Answer 2 · 2019-04-21T14:41:29.383

I reckon we can achieve the desired need with different approaches. As far as I have been aware of externalising Log4j2 configuration file in Grails 3, we could use either LogerContext or System.setProperty. The latter could be done as instructed in the post. My suggestion, as well as the demonstration for this question, is to use LogerContext as described in Logging Separation section of Log4j2 manual.

import org.apache.logging.log4j.LogManager
import org.apache.logging.log4j.core.LoggerContext

class BootStrap {

    def init = { servletContext ->
        LoggerContext context = (LoggerContext) LogManager.getContext(false)

        String userHome =  System.getProperty("user.home")
        String pathname = ""
        if (grails.util.Environment.isDevelopmentMode()) {
            pathname = userHome + "/.myConfigurations/log4j2-dev.xml"
        } else {
            pathname = userHome + "/.myConfigurations/log4j2-prod.xml"
        }
        File file = new File(pathname)
        // this will force a reconfiguration
        context.setConfigLocation(file.toURI())
    }
}

Please take a look at my project uploaded to Bitbucket. In this project, I tried to log a message after starting the application. The log.info was called in Application.groovy. Start the application within grails 3.3.9, you will have to run run-app to test development or prod run-app to test production mode.

Logging in Grails: reloadable external configuration with Log4j2

2 Answers2