shafirov / klogging

Kotlin logging, both js and jvm

KLogging

KLogging provides unified logging API, which you can use from Kotlin code targeted for JVM, Javascript and common kotlin. The library is inspired by

• code at [https://github.com/MicroUtils/kotlin-logging]
• and discussion at [http://stackoverflow.com/questions/34416869/idiomatic-way-of-logging-in-kotlin]

Download

	allprojects {
		repositories {
			...
			maven { url 'https://jitpack.io' }
		}
	}

Use these dependencies per kotlin module respectively:

compile 'com.github.shafirov.klogging:klogging.common:1.2.10'
compile 'com.github.shafirov.klogging:klogging.js:1.2.10'
compile 'com.github.shafirov.klogging:klogging.jvm:1.2.10'

Versions will be updated with same kotlin version

Usage

KLogger class features 5 levels of logging (to mirror that of SLF4J): trace, debug, info, warn, error with 2 flavors each:

logger.trace("This string will be evaluated regardless if trace enabled = ${logger.isTraceEnabled}")
logger.trace {"This string will not be evaluated unless trace enabled = ${logger.isTraceEnabled}"}

To obtain an instance of a logger you need to call one of the logger() methods of KLoggers (please note that JVM version of this class provides more overloads) or use mix it in:

class Foo {
    val logger = KLoggers.logger(this)
    
    fun test() {
        logger.info("Have some logging!")    
    }
}

class Bar : WithLogging by KLoggerHolder() {
    fun test() {
        logger.info("Have some logging!")    
    }
}
 
class Baz {
    companion object: WithLogging by KLoggerHolder() 
    
    fun test() {
        logger.info("Have some logging!")    
    }
} 

Logger is invokable:

class Foo {
    val logger = KLoggers.logger(this)
    
    fun test() {
        logger("Have some logging!")    
    }
}

For file-level loggers I recommend following IntelliJ IDEA live template:

<template name="log" value="private val log = klogging.KLoggers.logger(&quot;$LOGGER_NAME$&quot;)" description="Logger" toReformat="false" toShortenFQNames="true">
  <variable name="LOGGER_NAME" expression="groovyScript(&quot;com.intellij.openapi.module.ModuleUtil.findModuleForFile(_editor.virtualFile, _editor.project).name + \&quot;/\&quot; + _editor.virtualFile.name&quot;) " defaultValue="" alwaysStopAt="false" />
  <context>
    <option name="KOTLIN_TOPLEVEL" value="true" />
  </context>
</template>