Introduction

Colotok is a Kotlin Multiplatform logging library.

Feature

✅ Print log with color
✅ Formatter
✅ Print log where you want
　🌟 ConsoleProvider
　🌟 FileProvider
　🌟 StreamProvider
✅ Log Rotation
　🌟 SizeBaseRotation
　🌟 DateBaseRotation (duration based)
✅ Customize output location
　🌟 example print log into slack
✅ Structured Logging
✅ MDC (Mapped Diagnostic Context)
✅ Metrics Collection

Integration

basic dependency

dependencies {
    // add this line
    implementation("io.github.milkcocoa0902:colotok:0.5.0")
}

For a Kotlin Multiplatform project, add the root artifact to commonMain:

kotlin {
    sourceSets {
        commonMain.dependencies {
            implementation("io.github.milkcocoa0902:colotok:0.5.0")
        }
    }
}

The core module, colotok-coroutines, and colotok-loki support JVM, Android, JS/Node, iosArm64, iosSimulatorArm64, and macosArm64. Apple x86 targets (iosX64 and macosX64) are not published in 0.5.0. Gradle module metadata selects the target-specific variant from the common dependency; do not add target-suffixed coordinates manually.

Plugins

Colotok provides several plugins to extend its functionality:

plugin	artifact	feature	Platform
colotok-coroutines	`io.github.milkcocoa0902:colotok-coroutines:0.5.0`	coroutine support	Multi Platform
colotok-slf4j	`io.github.milkcocoa0902:colotok-slf4j:0.5.0`	SLF4J 1.7.x bindings (JVM only)	JVM
colotok-slf4j2	`io.github.milkcocoa0902:colotok-slf4j2:0.5.0`	SLF4J 2.x bindings (JVM only)	JVM
colotok-cloudwatch	`io.github.milkcocoa0902:colotok-cloudwatch:0.5.0`	send logs to AWS CloudWatch	JVM
colotok-loki	`io.github.milkcocoa0902:colotok-loki:0.5.0`	send logs to Grafana Loki	Multi Platform

Dependencies

Structured logging requires the Kotlin serialization compiler plugin because message classes use @Serializable. The colotok artifact already exposes the serialization runtime required by its public API, so a separate runtime dependency is normally unnecessary.

plugins {
    // Use the same version as your Kotlin Gradle plugin.
    kotlin("plugin.serialization") version "2.3.21"
}

Usage

Configuration

configure colotok with code.
see below.

val logger = ColotokLoggerContext()
    .addProvider(ConsoleProvider(ConsoleProviderConfig()))
    .getLogger()

more details config

import okio.Path.Companion.toPath

val fileProvider = FileProvider("test.log".toPath()) {
    level = LogLevel.INFO
    // use size-based rotation
    rotation = SizeBaseRotation(size = 4096L)
}

val logger = ColotokLoggerContext()
    .addProvider(ConsoleProvider(ConsoleProviderConfig().apply {
        // show above info level in console
        level = LogLevel.INFO
    }))
    .addProvider(fileProvider)
    .getLogger()

logger.trace("TRACE LEVEL LOG")
logger.debug("DEBUG LEVEL LOG")
logger.info("INFO LEVEL LOG")
logger.warn("WARN LEVEL LOG")
logger.error("ERROR LEVEL LOG")

Print

now, you can print log into your space.

logger.trace("TRACE LEVEL LOG")
logger.debug("DEBUG LEVEL LOG")
logger.info("INFO LEVEL LOG")
logger.warn("WARN LEVEL LOG")
logger.error("ERROR LEVEL LOG")

logger.atInfo {
    print("in this block")
    print("all of logs are printed out with INFO level")
}

// or you can add additional parameters
logger.info("INFO LEVEL LOG", mapOf("param1" to "a custom attr"))

Last modified: 07 September 2026