Napier is a logger library for Kotlin Multiplatform.
It supports Android, Darwin(iOS, macOS, watchOS, tvOS), JVM, JavaScript.
Logs written in common module are displayed on logger viewer of each platform.

Preview

Android

format: [Class name]$[Method name]: [Your log]

uses the android.util.Log(Logcat)

Darwin(iOS, macOS, watchOS, tvOS)[Intel/Apple silicon]

format: [Date time][Symbol][Log level][Class name].[Method name] - [Your log]

Added [async] label at the end, if it is called from suspend functions.

uses the print

JavaScript

uses the console.log

JVM

uses the java.util.logging.Logger

• common sample code

class Sample {

    fun hello(): String {
        Napier.v("Hello napier")
        Napier.d("optional tag", tag = "your tag")

        return "Hello Napier"
    }

    suspend fun suspendHello(): String {
        Napier.i("Hello")

        delay(3000L)

        Napier.w("Napier!")

        return "Suspend Hello Napier"
    }

    fun handleError() {
        try {
            throw Exception("throw error")
        } catch (e: Exception) {
            Napier.e("Napier Error", e)
        }
    }
}

Download

Repository

You can download this library from MavenCentral or jCenter repository.

• Maven central

You can download this from 1.4.1.
Package name is io.github.aakira

repositories {
    mavenCentral()
}

• jCenter

You can download this until 1.4.1.
Package name is com.github.aakira

repositories {
    jCenter()
}

Version

Set the version name in your build.gradle

def napierVersion = "[latest version]"

Common

Add the dependency to your commonMain dependencies

• groovy

sourceSets {
    commonMain {
        dependencies {
            // ...
            implementation "io.github.aakira:napier:$napierVersion"
        }
    }
}

• kts

sourceSets {
    val commonMain by getting {
        dependencies {
            implementation("io.github.aakira:napier:$napierVersion")
        }
    }
}

Usage

How to use

Common module

// verbose log
Napier.v("Hello napier")
Napier.v { "Hello napier" }

// you can set a tag for each log
Napier.d("optional tag", tag = "your tag")
Napier.d(tag = "your tag") { "optional tag" }

try {
    ...
} catch (e: Exception) {
    // you can set the throwable
    Napier.e("Napier Error", e)
    Napier.e(e) { "Napier Error" }
}

// you can also use top-level function
log { "top-level" }
log(tag = "your tag") { "top-level" }

Initialize

You must initialize the Napier in your module.

Android

Napier.base(DebugAntilog())

iOS

• Write initialize code in your kotlin mpp project.

fun debugBuild() {
    Napier.base(DebugAntilog())
}

|argument|type|description| |-|-| |coroutinesSuffix|Boolean|Added [async] label at the end, if it is called from suspend functions|

• Call initialize code from ios project.

NapierProxyKt.debugBuild()

Clear antilog

Napier.takeLogarithm()

Log level

Platform	Sample
VERBOSE	Napier.v()
DEBUG	Napier.d()
INFO	Napier.i()
WARNING	Napier.w()
ERROR	Napier.e()
ASSERT	Napier.wtf()

Run background thread

You can use this library on the background thread on iOS using Kotlin.coroutines as native-mt.

• Define scope

internal val mainScope = SharedScope(Dispatchers.Main)

internal val backgroundScope = SharedScope(Dispatchers.Default)

internal class SharedScope(private val context: CoroutineContext) : CoroutineScope {
    private val job = Job()
    private val exceptionHandler = CoroutineExceptionHandler { _, throwable ->
        println("[Coroutine Exception] $throwable")
    }

    override val coroutineContext: CoroutineContext
        get() = context + job + exceptionHandler
}

• Usage

backgroundScope.launch {
    suspendFunction()
}

Advancement

You can inject custom Antilog.
So, you should change Antilogs in debug build or release build.

Crashlytics

Crashlytics AntiLog samples

Sample projects use the Firebase Crashlytics.
You must set authentication files to android/google-services.json and ios/Napier/GoogleService-Info.plist.

Check the firebase document. [Android, iOS]

• Android

Write this in your application class.

if (BuildConfig.DEBUG) {
    // Debug build

    // disable firebase crashlytics
    FirebaseCrashlytics.getInstance().setCrashlyticsCollectionEnabled(false)
    // init napier
    Napier.base(DebugAntilog())
} else {
    // Others(Release build)

    // enable firebase crashlytics
    FirebaseCrashlytics.getInstance().setCrashlyticsCollectionEnabled(true)
    // init napier
    Napier.base(CrashlyticsAntilog(this))
}

• iOS

Write this in your AppDelegate.

#if DEBUG
// Debug build

// init napier
NapierProxyKt.debugBuild()

#else
// Others(Release build)

// init firebase crashlytics
FirebaseApp.configure()

// init napier
NapierProxyKt.releaseBuild(antilog: CrashlyticsAntilog(
    crashlyticsAddLog: { priority, tag, message in
        Crashlytics.crashlytics().log("\(String(describing: tag)): \(String(describing: message))")
},
    crashlyticsSendLog: { throwable in
        Crashlytics.crashlytics().record(error: throwable)
}))
#endif

License

Copyright (C) 2019 A.Akira

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

https://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

Credit

This library is inspired by Timber.
I recommend using it if it supports kotlin multiplatform project.😜

Thanks for advice.
@horita-yuya, @terachanple