Kermit Crash Logging - Crashlytics

With the kermit-crashlytics module, you can setup kermit to automatically send bread crumbs and crash reports to Firebase Crashlytics

If you just want to write crash reports without using Kermit logging, see CrashKiOS

Step 1: Add Crashlytics to Your Native Project

If you already have your app setup with Crashlytics, you can skip this step, otherwise follow the steps in the Firebase docs to add Crashlytics crash reporting to both your Android and iOS

Step 2: Setup Kermit Crash Logging

First, make sure you have a dependency on kermit and kermit-crashlytics artifacts in your commonMain source set in your shared modules build.gradle

    sourceSets {
        commonMain {
            dependencies {
                implementation("co.touchlab:kermit:${KERMIT_VERSION}")
                implementation("co.touchlab:kermit-crashlytics:${KERMIT_VERSION}")
            }
        }
...

Second, setup the CrashlyticsLogWriter with your Logger. The constructor for both platforms is the same, so in shared code, or in platform-specific Kotlin, run the following:

Logger.addLogWriter(CrashlyticsLogWriter())

(Static Config would be similar)

On either platform, you should make sure logging is configured immediately after Crashlytics is initialized, to avoid a gap where some other failure may happen but logging is not capturing info.

iOS

For iOS, besides regular logging, you will also want to configure Kotlin's uncaught exception handling. kermit-crashlytics provides the setupCrashlyticsExceptionHook helper function to handle this for you.

If you don't need to make kermit logging calls from Swift/Objective C code, we recommend not exporting Kermit in the framework exposed to your iOS app. To setup Kermit configuration you can make a top level helper method in the iosMain source set that you call from Swift code. The same rule of thumb applies to kermit-crashlytics and since the added api is only needed for configuration, a Kotlin helper method is almost always the best option. Here is a basic example.

// in Kermit/AppInit.kt
fun setupKermit() {
    Logger.addLogWriter(CrashlyticsLogWriter())
    setupCrashlyticsExceptionHook(Logger)
}

// in AppDelegate.swift
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    ...
    func application(
        _ application: UIApplication, 
        didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
    ) -> Bool {
        // Note: This MUST be the first two statement, in this order, for Kermit and Crashlytics
        // to handle any crashes in your app launch. 
        // If the app crashes before these calls run, it will not show up properly in the dashboard
        FirebaseApp.configure()
        AppInitKt.setupKermit()
        //...
    }
}

Dynamic Frameworks

If you are building dynamic frameworks, you'll need to configure the linker. See the CrashKiOS docs.

NSExceptionKt

CrashKiOS and Kermit previously created 2 reports on a crash because none of the crash reporting clients had an obvious way to do one. Rick Clephas has done some excellent work figuring that out with NSExceptionKt. CrashKiOS and Kermit now use parts of NSExceptionKt for crash handling.