logbook

Kotlin/Multiplatform logging library.

Overview

// Logbook.WithDefaults gives us default log levels, formatting, and a console outlet:
class ParserLog : Logbook.WithDefaults() {
    // the logger's name is inferred as "Parser" but can be overridden:
    // override val name = "Parsing"
    
    // declare a new log level that is lower than debug:
    val trace by level(placeBefore = debug) {
        colorInfo = ColorInfo(0x999999) // gray
    }
    
    // set the format of the logger, example output: 2025-02-04T20:46:55Z Parser - warning : something happened!!
    override fun format(entry: LogEntry) =
        StartChunks + entry.time.utc.formatAsStandard() + " " + entry.logbook + " - " + entry.level + " : " + data.toString() + EndChunks
    
    // set the minimum log level to trace:
    init {
        minimumLevel = trace
    }
    
    // add companion object to avoid having to manually construct instance:
    companion object : ParserLog()
}

Installation

Simply add a dependency on logbook to your Gradle project:

repositories {
    mavenCentral()
}

// for Kotlin/Multiplatform projects:
kotlin {
    sourceSets {
        commonMain.dependencies {
            implementation("moe.micha:logbook:$version")
        }
    }
}

// for Kotlin/JVM projects:
kotlin {
    dependencies {
        implementation("moe.micha:logbook:$version")
    }
}

Replace $version with the version you want, a list of which can be retrieved on Maven Central.

Contributing

I would love for people to contribute to logbook!

If you feel like the library is missing something or you've encountered a bug, please let me know with a GitHub Issue! No need to be shy, there is no format to these Issues, just type whatever you want :)

If you've already got experience with Kotlin, feel free to work on a fix or feature on your own and submitting a Pull Request! There are no official contribution guidelines, just try your best and I'll see if I can fix some issues if there are any :)

To Do

• Handle multi-line log messages (such as stack traces).
• Improve timestamp formatting by using Chunks as well.
  • Extend Chunks to be able to have a min and max width, padding, alignment, etc.
  • Also support relative timestamp (relative to the start of the program or to the last log message, etc.)
• Add some sort of grouping mechanism (such as JavaScript's console.group).
  • Maybe provide two separate functions – groupImplicitly and groupExplicitly. groupExplicitly would take a block in which a sublogger is accessible, which prints to the group. groupImplicitly would cause all following calls to the logger to be treated as though they were done on a sublogger. Just some ideas.
• Add a simple file outlet.
  • Add option to either append to existing file or clear file on every boot.
• Add a rotating file outlet.