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 distributable applications. Distributable applications are self-contained, installable binaries which include all the Java runtime components they need, without requiring an installed JDK on the target system.

Jlink will take care of bundling only the necessary Java Modules in the distributable package to minimize package size, but you must still configure the Gradle plugin to tell it which modules you need (see the Configuring included JDK modules section).

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.

Configuring included JDK modules

The Gradle plugin uses jlink to minimize a distributable size by including only necessary JDK modules.

At this time, the Gradle plugin does not automatically determine necessary JDK Modules. Failure to provide the necessary modules will not cause compilation issues, but will lead to ClassNotFoundException at runtime.

If you encounter ClassNotFoundException when running a packaged application or runDistributable task, you can include additional JDK modules using modules DSL method (see example below).

You can determine, which modules are necessary either by hand or by running suggestModules task. suggestModules uses the jdeps static analysis tool to determine possible missing modules. Note, that the output of the tool might be incomplete or list unnecessary modules.

If a distributable size is not critical, you may simply include all runtime modules as an alternative by using includeAllModules DSL property.

compose.desktop {
    application {
        nativeDistributions {
            modules("java.sql")
            // alternatively: includeAllModules = true
        }
    }
}

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)

Signing & notarization on macOS

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:

See our tutorial on how to sign and notarize your application.

Specifying package version

You must specify a package version for native distribution packages.

You can use the following DSL properties (in order of descending priority):

• nativeDistributions.<os>.<packageFormat>PackageVersion specifies a version for a single package format;
• nativeDistributions.<os>.packageVersion specifies a version for a single target OS;
• nativeDistributions.packageVersion specifies a version for all packages;

compose.desktop {
    application {
        nativeDistributions {
            // a version for all distributables
            packageVersion = "..." 
            
            linux {
              // a version for all Linux distributables
              packageVersion = "..." 
              // a version only for the deb package
              debVersion = "..." 
              // a version only for the rpm package
              rpmVersion = "..." 
            }
            macOS {
              // a version for all macOS distributables
              packageVersion = "..."
              // a version only for the dmg package
              dmgVersion = "..." 
              // a version only for the pkg package
              pkgVersion = "..." 
            }
            windows {
              // a version for all Windows distributables
              packageVersion = "..."  
              // a version only for the msi package
              msiVersion = "..."
              // a version only for the exe package
              exeVersion = "..." 
            }
        }
    }
}

Versions must follow the rules:

• For dmg and pkg:
  • The format is MAJOR[.MINOR][.PATCH], where:
    • MAJOR is an integer > 0;
    • MINOR is an optional non-negative integer;
    • PATCH is an optional non-negative integer;
• For msi and exe:
  • The format is MAJOR.MINOR.BUILD, where:
    • MAJOR is a non-negative integer with a maximum value of 255;
    • MINOR is a non-negative integer with a maximum value of 255;
    • BUILD is a non-negative integer with a maximum value of 65535;
• For deb:
  • The format is [EPOCH:]UPSTREAM_VERSION[-DEBIAN_REVISION], where:
    • EPOCH is an optional non-negative integer;
    • UPSTREAM_VERSION
      • may contain only alphanumerics and the characters ., +, -, ~;
      • must start with a digit;
    • DEBIAN_REVISION
      • is optional;
      • may contain only alphanumerics and the characters ., +, ~;
  • See Debian documentation for more details;
• For rpm:
  • A version must not contain the - (dash) character.

Customizing JDK version

The plugin uses jpackage, for which you should be using at least JDK 15. 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_15")
    }
}

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).
• licenseFile — application's license (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"
            licenseFile.set(project.file("LICENSE.txt"))
        }
    }
}

Packaging resources

There are multiple ways to package and load resources with Compose for Desktop.

JVM resource loading

Since Compose for Desktop uses JVM platform, you can load resources from a jar file using java.lang.Class API. Put a file under src/main/resources, then access it using Class::getResource or Class::getResourceAsStream.

Adding files to packaged application

In some cases putting and reading resources from jar files might be inconvenient. Or you may want to include a target specific asset (e.g. a file, that is included only into a macOS package, but not into a Windows one).

Compose Gradle plugin can be configured to put additional resource files under an installation directory.

To do so, specify a root resource directory via DSL:

compose.desktop {
    application {
        mainClass = "MainKt"
        nativeDistributions {
            targetFormats(TargetFormat.Dmg, TargetFormat.Msi, TargetFormat.Deb)
            packageVersion = "1.0.0"

            appResourcesRootDir.set(project.layout.projectDirectory.dir("resources"))
        }
    }
}

In the example above a root resource directory is set to <PROJECT_DIR>/resources.

Compose Gradle plugin will include all files under the following subdirectories:

1. Files from <RESOURCES_ROOT_DIR>/common will be included into all packages.
2. Files from <RESOURCES_ROOT_DIR>/<OS_NAME> will be included only into packages for a specific OS. Possible values for <OS_NAME> are: windows, macos, linux.
3. Files from <RESOURCES_ROOT_DIR>/<OS_NAME>-<ARCH_NAME> will be included only into packages for a specific combination of OS and CPU architecture. Possible values for <ARCH_NAME> are: x64 and arm64. For example, files from <RESOURCES_ROOT_DIR>/macos-arm64 will be included only into packages built for Apple Silicon Macs.

Included resources can be accessed via compose.application.resources.dir system property:

import java.io.File

val resourcesDir = File(System.getProperty("compose.application.resources.dir"))

fun main() {
    println(resourcesDir.resolve("resource.txt").readText())
}

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")
    }
}

Platform-specific options

Platform-specific options should be set using the corresponding DSL blocks:

compose.desktop {
    application {
        nativeDistributions {
            macOS {
                // macOS specific options
            }
            windows {
                // Windows specific options
            }
            linux {
                // Linux specific options
            }
        }
    }
}

The following platform-specific options are available (the usage of non-documented properties is not recommended):

• All platforms:
  • iconFile.set(File("PATH_TO_ICON")) — a path to a platform-specific icon for the application. (see the section App icon for details);
  • packageVersion = "1.0.0" — a platform-specific package version (see the section Specifying package version for details);
  • installationPath = "PATH_TO_INSTALL_DIR" — an absolute or relative path to the default installation directory;
    • On Windows dirChooser = true may be used to enable customizing the path during installation.
• Linux:
  • packageName = "custom-package-name" overrides the default application name;
  • debMaintainer = "maintainer@example.com" — an email of the deb package's maintainer;
  • menuGroup = "my-example-menu-group" — a menu group for the application;
  • appRelease = "1" — a release value for the rpm package, or a revision value for the deb package;
  • appCategory = "CATEGORY" — a group value for the rpm package, or a section value for the deb package;
  • rpmLicenseType = "TYPE_OF_LICENSE" — a type of license for the rpm package;
  • debPackageVersion = "DEB_VERSION" — a deb-specific package version (see the section Specifying package version for details);
  • rpmPackageVersion = "RPM_VERSION" — a rpm-specific package version (see the section Specifying package version for details);
• macOS:
  • bundleID — a unique application identifier;
    • May only contain alphanumeric characters (A-Z,a-z,0-9), hyphen (-) and period (.) characters;
    • Use of a reverse DNS notation (e.g. com.mycompany.myapp) is recommended;
  • packageName — a name of the application;
  • dockName — a name of the application displayed in the menu bar, the "About " menu item, in the dock, etc. Equals to packageName by default.
  • signing and notarization — see the corresponding tutorial for details;
  • dmgPackageVersion = "DMG_VERSION" — a dmg-specific package version (see the section Specifying package version for details);
  • pkgPackageVersion = "PKG_VERSION" — a pkg-specific package version (see the section Specifying package version for details);
  • infoPlist — see the section Customizing Info.plist on macOS for details;
• Windows:
  • console = true adds a console launcher for the application;
  • dirChooser = true enables customizing the installation path during installation;
  • perUserInstall = true enables installing the application on a per-user basis
  • menuGroup = "start-menu-group" adds the application to the specified Start menu group;
  • upgradeUuid = "UUID" — a unique ID, which enables users to update an app via installer, when an updated version is newer, than an installed version. The value must remain constant for a single application. See the link for details on generating a UUID.
  • msiPackageVersion = "MSI_VERSION" — a msi-specific package version (see the section Specifying package version for details);
  • exePackageVersion = "EXE_VERSION" — a pkg-specific package version (see the section Specifying package version for details);

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"))
            }
        }
    }
}

Customizing Info.plist on macOS

We aim to support important platform-specific customization use-cases via declarative DSL. However, the provided DSL is not enough sometimes. If you need to specify Info.plist values, that are not modeled in the DSL, you can work around by specifying a piece of raw XML, that will be appended to the application's Info.plist.

Example: deep linking into macOS apps

1. Specify a custom URL scheme:

// build.gradle.kts
compose.desktop {
    application {
        mainClass = "MainKt"
        nativeDistributions {
            targetFormats(TargetFormat.Dmg)
            packageName = "Deep Linking Example App"
            macOS {
                bundleID = "org.jetbrains.compose.examples.deeplinking"
                infoPlist {
                    extraKeysRawXml = macExtraPlistKeys
                }
            }
        }
    }
}

val macExtraPlistKeys: String
    get() = """
      <key>CFBundleURLTypes</key>
      <array>
        <dict>
          <key>CFBundleURLName</key>
          <string>Example deep link</string>
          <key>CFBundleURLSchemes</key>
          <array>
            <string>compose</string>
          </array>
        </dict>
      </array>
    """
"""

2. Use java.awt.Desktop to set up a URI handler:

// src/main/main.kt

import androidx.compose.material.MaterialTheme
import androidx.compose.material.Text
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.setValue
import androidx.compose.ui.window.singleWindowApplication
import java.awt.Desktop

fun main() {
    var text by mutableStateOf("Hello, World!")

    try {
        Desktop.getDesktop().setOpenURIHandler { event ->
            text = "Open URI: " + event.uri
        }
    } catch (e: UnsupportedOperationException) {
        println("setOpenURIHandler is unsupported")
    }

    singleWindowApplication {
        MaterialTheme {
            Text(text)
        }
    }
}

3. Run ./gradlew runDistributable.
4. Links like compose://foo/bar are now redirected from a browser to your application.

Obfuscation

To obfuscate Compose Multiplatform JVM applications the standard approach for JVM applications works. With the task packageUberJarForCurrentOS one could generate a JAR file which could be later obfuscated using ProGuard or R8.

ProGuard example

// build.gradle.kts

// Add ProGuard to buildscript classpath
buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("com.guardsquare:proguard-gradle:7.1.1") {
            exclude("com.android.tools.build")
        }
    }
}

// ...

// Define task to obfuscate the JAR and output to <name>.min.jar
tasks.register<ProGuardTask>("obfuscate") {
    val packageUberJarForCurrentOS by getting
    dependsOn(packageUberJarForCurrentOS)
    val files = packageUberJarForCurrentOS.outputs.files
    injars(files)
    outjars(files.map { file -> File(file.parentFile, "${file.nameWithoutExtension}.min.jar") })

    val library = if (System.getProperty("java.version").startsWith("1.")) "lib/rt.jar" else "jmods"
    libraryjars("${System.getProperty("java.home")}/$library")

    configuration("proguard-rules.pro")
}