Grails and Logback: Provide default logback configuration for development environment

The main motivation is to have a custom logger setup, which every developer can easily adjust. Also, we don't want to put logback config, which is meant for developers only, on the class path.

We can place logback.xml into the root folder of our project and then pass it when running up the application

grails -Dlogback.configurationFile=logback.xml run-app

The biggest disadvantage is: it is annoying to always include additional properties in the command line and it also means you need to tell that to the new developers. Also, it is not following Grails principle "convention over configuration".

We need to provide the default configuration for the development mode if logback.configurationFile property is not set.

So we hook after compilation event as follows. Create or open scripts/_Events.groovy file in your project folder.

Here is the content of _Events.groovy file.

	import ch.qos.logback.classic.Level
	import ch.qos.logback.classic.Logger
	import ch.qos.logback.classic.LoggerContext
	import ch.qos.logback.classic.encoder.PatternLayoutEncoder
	import ch.qos.logback.classic.joran.JoranConfigurator
	import ch.qos.logback.core.ConsoleAppender
	import grails.util.Environment
	import org.apache.commons.logging.Log
	import org.apache.commons.logging.LogFactory
	import org.slf4j.LoggerFactory;
	Log log = LogFactory.getLog("_Events")
	def activateLogbackFromConfigFile = { LoggerContext loggerContext ->
	JoranConfigurator configurator = new JoranConfigurator()
	configurator.context = loggerContext
	configurator.doConfigure('logback-config-dev.xml')
	}
	def activateLogbackProgrammatically = { LoggerContext loggerContext ->
	PatternLayoutEncoder encoder = new PatternLayoutEncoder()
	encoder.context = loggerContext
	encoder.pattern = "%date{ISO8601} Thread=\"%thread\" %-5level logger=\"%logger{136}\" message=\"%msg\"%n"
	encoder.start()
	ConsoleAppender consoleAppender = new ConsoleAppender()
	consoleAppender.name = 'console'
	consoleAppender.context = loggerContext
	consoleAppender.encoder = encoder
	Logger rootLogger = LoggerFactory.getLogger(Logger.ROOT_LOGGER_NAME)
	rootLogger.level = Level.WARN
	rootLogger.addAppender(consoleAppender)
	loggerContext.getLogger("com.example").level = Level.INFO
	// loggerContext.getLogger("org.codehaus.groovy.grails").level = Level.INFO
	// loggerContext.getLogger("org.springframework").level = Level.INFO
	// loggerContext.getLogger("org.hibernate").level = Level.INFO
	// loggerContext.getLogger("net.sf.ehcache.hibernate").level = Level.INFO
	// loggerContext.getLogger("org.springframework.web.client").level = Level.INFO
	consoleAppender.start()
	}
	eventCompileEnd = {
	boolean isCurrentEnvDevelopment = Environment.DEVELOPMENT.equals(Environment.currentEnvironment)
	if (isCurrentEnvDevelopment) {
	String logbackConfig = System.properties["logback.configurationFile"]
	if (!logbackConfig) {
	logbackConfig = System.env["logback.configurationFile"]
	}
	boolean isLogbackConfigProvided = logbackConfig != null
	if (isLogbackConfigProvided) {
	LogFactory.getLog("_Events").info "Logback is using: $logbackConfig"
	} else {
	log.info 'Logback is set for development mode. Change logback-config-dev.xml in order to adjust logging levels or change logging programmatically in _Events.groovy script.'
	// if we are in dev environment and logback is not provided, use this configuration
	LoggerContext loggerContext = LoggerFactory.getILoggerFactory()
	loggerContext.reset()
	// activateLogbackFromConfigFile loggerContext
	// or you can do this for dev needs (replace doConfigure method call)
	activateLogbackProgrammatically loggerContext
	}
	}
	}

view raw _Events.groovy hosted with ❤ by GitHub

In this example logback-config-dev.xml is ment to be stored in the project root folder.