kmp-logger

A small, dependency-free multiplatform logger for Kotlin/Multiplatform projects. Used across Asamm projects (Locus Map, Locus GIS, Locus API).

Targets: Android · JVM · iOS (arm64 + simulator arm64) · JS (browser)

Package: com.asamm.kmp.logger

Install

JitPack (public, anonymous) — Android / JVM / JS only

// settings.gradle.kts
dependencyResolutionManagement {
    repositories {
        maven("https://jitpack.io")
    }
}

// build.gradle.kts
dependencies {
    implementation("com.github.asamm:kmp-logger:0.9.1")
}

⚠️ iOS is not published via JitPack. The iOS klib publish step pushes the JitPack build past its container status-check timeout, making releases flaky. JitPack therefore only ships Android, JVM, JS, and the Kotlin Multiplatform metadata. Kotlin/Multiplatform projects targeting iOS must consume kmp-logger from GitHub Packages instead — that channel includes all platforms.

GitHub Packages (Asamm team)

// settings.gradle.kts
dependencyResolutionManagement {
    repositories {
        maven("https://maven.pkg.github.com/asamm/kmp-logger") {
            credentials {
                username = System.getenv("GPR_USERNAME")
                password = System.getenv("GPR_TOKEN")
            }
        }
    }
}

dependencies {
    implementation("com.asamm.kmp:kmp-logger:0.9.1")
}

Kotlin/Multiplatform consumers resolve the correct platform variant automatically via Gradle module metadata. Android-only or JVM-only (non-KMP) consumers can also depend on a specific platform artifact directly: com.asamm.kmp:kmp-logger-android:0.9.1, com.asamm.kmp:kmp-logger-jvm:0.9.1, com.asamm.kmp:kmp-logger-js:0.9.1.

Usage

import com.asamm.kmp.logger.logD
import com.asamm.kmp.logger.logE
import com.asamm.kmp.logger.LogCategory
import com.asamm.kmp.logger.LogPriority

// Define a category (once, somewhere central).
val MY_CATEGORY = LogCategory(
    tagPrefix = "MAP-",
    minPriority = LogPriority.DEBUG,
    public = false, // set true if the user may change minPriority at runtime
    title = "Map rendering",
    desc = "Logs from the map rendering pipeline"
)

// Log.
logD(MY_CATEGORY) { "tile loaded: $tileId" }
logE(MY_CATEGORY, ex = throwable) { "failed to render tile $tileId" }

The msg parameter is a lambda — it is only evaluated when the category's minimum priority allows the call, so disabled categories have zero allocation cost.

Custom backends

Register a custom ILogger implementation to route log calls elsewhere (file sink, crash reporter, etc.):

Logger.registerLogger(object : ILogger {
    override fun v(tag: String, msg: String) { /* ... */ }
    override fun i(tag: String, msg: String) { /* ... */ }
    override fun d(tag: String, msg: String, ex: Throwable?) { /* ... */ }
    override fun w(tag: String, msg: String, ex: Throwable?) { /* ... */ }
    override fun e(tag: String, msg: String, ex: Throwable?) { /* ... */ }
})

If no custom logger is registered, the module falls back to a platform-appropriate default:

Platform	Backend
Android	android.util.Log (Logcat)
JVM	java.util.logging.Logger + ConsoleHandler
iOS	println()
JS	console.log / console.warn / console.error

Migrating from logger-asamm

The API is a straight descendant of com.asamm.loggerV2.*. Migration is a single rename:

com.asamm.loggerV2  →  com.asamm.kmp.logger

All DSL names (logV, logD, logI, logW, logE), LogCategory, LogPriority, and ILogger are preserved.

License

Apache 2.0