Gradle Shadow plugin

Prerequisites

Before starting this tutorial, clone the ktor-gradle-sample repository.

Configure the Shadow plugin

To build a Fat JAR, you need to configure the Shadow plugin first:

1. Open the build.gradle(.kts) file and add the plugin to the plugins block:

   plugins { id 'com.github.johnrengelman.shadow' version '7.0.0' }

   plugins { id("com.github.johnrengelman.shadow") version "7.0.0" }

2. Add the shadowJar task:

   shadowJar { manifest { attributes 'Main-Class': 'com.example.ApplicationKt' } }

   tasks{ shadowJar { manifest { attributes(Pair("Main-Class", "com.example.ApplicationKt")) } } }

   If you use EngineMain without the explicit main function, your Main-Class depends on the used engine and might look as follows: io.ktor.server.netty.EngineMain.

Build a Fat JAR

To build a Fat JAR, open the terminal and execute the shadowJar task created in the previous step:

When this build completes, you should see the ktor-gradle-sample-1.0-SNAPSHOT-all.jar file in the build/libs directory.

Run the application

To run the built application:

1. Go to the build/libs folder in a terminal.

2. Execute the following command to run the application:

   java -jar ktor-gradle-sample-1.0-SNAPSHOT-all.jar

3. Wait until the following message is shown:

   [main] INFO Application - Responding at http://0.0.0.0:8080 You can click the link to open the application in a default browser: