compose-jb/tutorials/Native_distributions_and_local_execution

Native distributions & local execution

What is covered

In this tutorial, we'll show you how to create native distributions (installers/packages) for all the supported systems. We will also demonstrate how to run an application locally with the same settings as for distributions.

Gradle plugin

org.jetbrains.compose Gradle plugin simplifies the packaging of applications into native distributions and running an application locally. Currently, the plugin uses jpackage for packaging self-contained applications.

Basic usage

The basic unit of configuration in the plugin is an application. An application defines a shared configuration for a set of final binaries. In other words, an application in DSL allows you to pack a bunch of files, together with a JDK distribution, into a set of compressed binary installers in various formats (.dmg, .deb, .msi, .exe, etc).

import org.jetbrains.compose.compose
import org.jetbrains.compose.desktop.application.dsl.TargetFormat

plugins {
    kotlin("jvm")
    id("org.jetbrains.compose")
}

dependencies {
    implementation(compose.desktop.currentOS)
}

compose.desktop {
    application {
        mainClass = "example.MainKt"

        nativeDistributions {
            targetFormats(TargetFormat.Dmg, TargetFormat.Msi, TargetFormat.Deb)
        }
    }
}

The plugin creates the following tasks:

• package<FormatName> (e.g. packageDmg or packageMsi) are used for packaging the app into the corresponding format. Note, that there is no cross-compilation support available at the moment, so the formats can only be built using the specific OS (e.g. to build .dmg you have to use macOS). Tasks that are not compatible with the current OS are skipped by default.
• package is a lifecycle task, aggregating all package tasks for an application.
• packageUberJarForCurrentOS is used to create a single jar file, containing all dependencies for current OS. The task is available starting from the M2 release. The task expects compose.desktop.currentOS to be used as a compile/implementation/runtime dependency.
• run is used to run an app locally. You need to define a mainClass — an fq-name of a class, containing the main function. Note, that run starts a non-packaged JVM application with full runtime. This is faster and easier to debug, than creating a compact binary image with minified runtime. To run a final binary image, use runDistributable instead.
• createDistributable is used to create a prepackaged application image a final application image without creating an installer.
• runDistributable is used to run a prepackaged application image.

Note, that the tasks are created only if the application block/property is used in a script.

After a build, output binaries can be found in ${project.buildDir}/compose/binaries.

Available formats

The following formats available for the supported operating systems:

• macOS — .dmg (TargetFormat.Dmg), .pkg (TargetFormat.Pkg)
• Windows — .exe (TargetFormat.Exe), .msi (TargetFormat.Msi)
• Linux — .deb (TargetFormat.Deb), .rpm (TargetFormat.Rpm)

Distributing Artifacts

By default, Apple does not allow users to execute unsigned applications downloaded from the internet. Users attempting to run such applications will be faced with an error like this:

To temporarily work around this issue, users can try a couple of things (after downloading to target machine, try commands in this order, do not attempt out of order):

• xattr -cr MyFancyProgram.app
• sudo spctl --master-disable
• Try right-clicking on the app, and select "Open", then when the dialog pops up, select "Open" again.

A more correct fix is to manually sign & notarize the application:

• Apple's Guide on Signing & Notarizing Applications
• JPackage Documentation on Signing MacOS Applications

Customizing JDK version

The plugin uses jpackage, which is available since JDK 14. Make sure you meet at least one of the following requirements:

• JAVA_HOME environment variable points to the compatible JDK version.
• javaHome is set via DSL:

compose.desktop {
    application {
        javaHome = System.getenv("JDK_14")
    }
}

Customizing output dir

compose.desktop {
    application {
        nativeDistributions {
            outputBaseDir.set(project.buildDir.resolve("customOutputDir"))
        }
    }
}

Customizing launcher

The following properties are available for customizing the application startup:

• mainClass — a fully-qualified name of a class, containing the main method;
• args — arguments for the application's main method;
• jvmArgs — arguments for the application's JVM.

compose.desktop {
    application {
        mainClass = "MainKt"
        jvmArgs += listOf("-Xmx2G") 
        args += listOf("-customArgument") 
    }
}

Customizing metadata

The following properties are available in the nativeDistributions DSL block:

• packageName — application's name (default value: Gradle project's name);
• version — application's version (default value: Gradle project's version);
• description — application's description (default value: none);
• copyright — application's copyright (default value: none);
• vendor — application's vendor (default value: none).

compose.desktop {
    application {
        nativeDistributions {
            packageName = "ExampleApp"
            version = "0.1-SNAPSHOT"
            description = "Compose Example App"
            copyright = "© 2020 My Name. All rights reserved."
            vendor = "Example vendor"
        }
    }
}

Customizing content

The plugin can configure itself, when either org.jetbrains.kotlin.jvm or org.jetbrains.kotlin.multiplatform plugins are used.

• With org.jetbrains.kotlin.jvm the plugin includes content from the main source set.
• With org.jetbrains.kotlin.multiplatform the plugin includes content a single jvm target. The default configuration is disabled if multiple JVM targets are defined. In this case, the plugin should be configured manually, or a single target should be specified (see below).

If the default configuration is ambiguous or not sufficient, the plugin can be configured:

• Using a Gradle source set

plugins {
    kotlin("jvm")
    id("org.jetbrains.compose")
} 

val customSourceSet = sourceSets.create("customSourceSet")
compose.desktop {
    application {
        from(customSourceSet)
    }
}

• Using a Kotlin JVM target:

plugins {
    kotlin("multiplatform")
    id("org.jetbrains.compose")
} 

kotlin {
    jvm("customJvmTarget") {}
}

compose.desktop {
    application {
        from(kotlin.targets["customJvmTarget"])
    }
}

• manually:
  • disableDefaultConfiguration can be used to disable the default configuration;
  • dependsOn can be used to add task dependencies to all plugin's tasks;
  • fromFiles can be used to specify files to include;
  • mainJar file property can be specified to point to a jar, containing a main class.

compose.desktop {
    application {
        disableDefaultConfiguration()
        fromFiles(project.fileTree("libs/") { include("**/*.jar") })
        mainJar.set(project.file("main.jar"))
        dependsOn("mainJarTask")
    }
}

App icon

The app icon needs to be provided in OS-specific formats:

• .icns for macOS;
• .ico for Windows;
• .png for Linux.

compose.desktop {
    application {
        nativeDistributions {
            macOS {
                iconFile.set(project.file("icon.icns"))
            }
            windows {
                iconFile.set(project.file("icon.ico"))
            }
            linux {
                iconFile.set(project.file("icon.png"))
            }
        }
    }
}