A home-grown logging library compatible with Kotlin Multiplatform.
Here at Airthings, we develop bleeding-edge libraries and applications to power our ever-increasing catalogue of software, so when we looked for a logging library that ticked a few boxes for us, we didn't find one.
So, we wrote one – and this is it.
In short, the following features are the core of this logging library:
- Compatible with Kotlin Multiplatform, at the moment supporting Android and iOS.
- Library comes with a set of default loggers (implementing the interface
LoggerFacility) that you can use out-of-the-box in your project. - Unlike other logging libraries, logging properties/arguments associated with log messages are separate from the message itself – Look below for an example.
- Easily extensible by providing own logging implementation in your app, and then attaching them to the logging manager – Look below for an example.
We're using JitPack.io to automatically distribute the library to users:
allprojects {
repositories {
maven("https://jitpack.io")
// …
}
}dependencies {
implementation("com.github.airthings:kmplog:<version>")
}For the last version of the library: https://github.com/Airthings/KmpLog/tags
The following normally needs to be done once when the app starts:
Somewhere in your App.kt file, which extends Application, insert the following:
class MyApp : Application() {
// …
override fun onCreate() {
super.onCreate()
// …
initializeLogging()
}
private fun initializeLogging() {
// Log to the console when in DEBUG only.
if (BuildConfig.DEBUG) {
LoggerFacility.register(
"${LoggerName.PRINTER}",
PrinterLoggerFacility()
)
}
// Log messages to the file system, can be uploaded later to a remote server for processing
// after getting the user's permission.
LoggerFacility.register(
"${LoggerName.FILE}",
FileLoggerFacility(
LogLevel.INFO,
logsFolder()
)
)
// Log messages to Firebase.
LoggerFacility.register(
"${LoggerName.FIREBASE}",
FirebaseLoggerFacility(AndroidFirebaseLoggerFacility())
)
}
}Somewhere in your AppDelegate.swift file, which extends UIApplicationDelegate, insert the following:
@UIApplicationMain
class MyAppDelegate: UIApplicationDelegate {
// …
func application(
_ application: UIApplication,
didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
) -> Bool {
// …
initializeLogging()
return true
}
private func initializeLogging() {
// Log to the console when in DEBUG only.
#if DEBUG
LoggerFacilityCompanion.shared.register(
name: "\(LoggerName.printer)",
facility: PrinterLoggerFacility()
)
#endif
// Log messages to the file system, can be uploaded later to a remote server for processing
// after getting the user's permission.
LoggerFacilityCompanion.shared.register(
name: "\(LoggerName.file)",
facility: FileLoggerFacility(
minimumLogLevel: LogLevel.info,
baseFolder: FileManager.logsFolder()
)
)
// Log messages to Firebase.
LoggerFacilityCompanion.shared.register(
name: "\(LoggerName.firebase)",
facility: FirebaseLoggerFacility(
facility: IosFirebaseLoggerFacility()
)
)
}
}Now, all you need to do is create instances of the Logger class and use it everywhere you want to log:
val logger = Logger("MyActivity")
// …
logger.info(
LogMessage(
message = "User signed in.",
args = listOf(
LogArg("user-id", userId),
LogArg("captcha-time", captchaTime)
)
)
)Due to the nature of KMP, the code in Swift is a bit more verbose:
logger.info(
message: LogMessage(
message: "User signed in.",
args: [
LogArg(label: "user-id", value: userId),
LogArg(label: "captcha-time", value: captchaTime)
]
)
)
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