We can let Grails log some extra information when the application starts. Like the process ID (PID) of the application and on which machine the application starts. And the time needed to start the application. The GrailsApp class has a property logStartupInfo which is true by default. If the property is true than some extra lines are logged at INFO and DEBUG level of the logger of our Application class.

So in order to see this information we must configure our logging in the logback.groovy file. Suppose our Application class is in the package mrhaki.grails.sample.Application then we add the following line to see the output of the startup logging on the console:

...
logger 'mrhaki.grails.sample.Application', DEBUG, ['STDOUT'], false
...

When we run our Grails application we see the following in our console:

...
INFO mrhaki.grails.sample.Application - Starting Application on mrhaki-jdriven.local with PID 20948 (/Users/mrhaki/Projects/blog/posts/sample/build/classes/main started by mrhaki in /Users/mrhaki/Projects/mrhaki.com/blog/posts/sample/)
DEBUG mrhaki.grails.sample.Application - Running with Spring Boot v1.2.3.RELEASE, Spring v4.1.6.RELEASE
INFO mrhaki.grails.sample.Application - Started Application in 8.29 seconds (JVM running for 9.906)
Grails application running at http://localhost:8080
...

If we want to add some extra logging we can override the logStartupInfo method:

package mrhaki.grails.sample

import grails.boot.GrailsApp
import grails.boot.config.GrailsAutoConfiguration
import grails.util.*
import groovy.transform.InheritConstructors

class Application extends GrailsAutoConfiguration {

    static void main(String[] args) {
        // Use extended GrailsApp to run.
        new StartupGrailsApp(Application).run(args)
    }

}

@InheritConstructors
class StartupGrailsApp extends GrailsApp {
    @Override
    protected void logStartupInfo(boolean isRoot) {
        // Show default info.
        super.logStartupInfo(isRoot)

        // And add some extra logging information.
        // We use the same logger if we get the
        // applicationLog property.
        if (applicationLog.debugEnabled) {
            final metaInfo = Metadata.getCurrent()
            final String grailsVersion = GrailsUtil.grailsVersion
            applicationLog.debug "Running with Grails v${grailsVersion}"

            final sysprops = System.properties
            applicationLog.debug "Running on ${sysprops.'os.name'} v${sysprops.'os.version'}"
        }
    }
}

If we run the application we see in the console:

...
DEBUG mrhaki.grails.sample.Application - Running with Spring Boot v1.2.3.RELEASE, Spring v4.1.6.RELEASE
DEBUG mrhaki.grails.sample.Application - Running with Grails v3.0.1
DEBUG mrhaki.grails.sample.Application - Running on Mac OS X v10.10.3
...

Written with Grails 3.0.1.

Original article

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