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]
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
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 = ${logger.isTraceEnabled}"}To obtain an instance of a logger you need to call one of the logger() methods of KLoggers
(please note that JVM version of this class provides more overloads) or use mix it in:
class Foo {
val logger = KLoggers.logger(this)
fun test() {
logger.info("Have some logging!")
}
}
class Bar : WithLogging by KLoggerHolder() {
fun test() {
logger.info("Have some logging!")
}
}
class Baz {
companion object: WithLogging by KLoggerHolder()
fun test() {
logger.info("Have some logging!")
}
}
Logger is invokable:
class Foo {
val logger = KLoggers.logger(this)
fun test() {
logger("Have some logging!")
}
}
For file-level loggers I recommend following IntelliJ IDEA live template:
<template name="log" value="private val log = klogging.KLoggers.logger("$LOGGER_NAME$")" description="Logger" toReformat="false" toShortenFQNames="true">
<variable name="LOGGER_NAME" expression="groovyScript("com.intellij.openapi.module.ModuleUtil.findModuleForFile(_editor.virtualFile, _editor.project).name + \"/\" + _editor.virtualFile.name") " defaultValue="" alwaysStopAt="false" />
<context>
<option name="KOTLIN_TOPLEVEL" value="true" />
</context>
</template>