Gradle experiments

Creating new gradle build

Find already downloaded gradle binaries in .gradle/wrapper/dists. For example:

alias gradle=~/.gradle/wrapper/dists/gradle-4.0.1-all/26awvqv6f41r14q9x72t4n0s/gradle-4.0.1/bin/gradle

And use to create your first project:

# Help on a specific task
gradle help --task wrapper

# New wrapper
gradle wrapper --gradle-version 4.0.1 --distribution-type all

Display project info:

./gradlew properties

Use our first custom task:

# Display all tasks
./gradlew tasks --all

# Execute task
./gradlew copy

After copy, let's zip our project's src folder:

./gradlew zip
unzip -ql build/distributions/hello-1.0.zip

Creating Multi-project Builds

Let's create our first sub project (wrapper + settings useless here):

# Init a new java-library build
mkdir jlib && cd jlib
../gradlew init --type java-library

# Add this new sub project
echo "include ':japp', ':jlib'" > settings.gradle

Consider using gw as a nice shortcut for using wrapper from anywhere with ease.

Writing gradle tasks

See changes in base/build.gradle and our new base task group when listing tasks :)

Writing gradle plugins

Good practice is to configure plugin properties in folder: buildSrc/src/main/resources/META-INF/gradle-plugins in order to use the plugin id.

Build environment

2 ways to declare a project property:

• via command line (like "gradle hello -Pverbose.level=info -PnoLogs")
• via gradle.properties (verbose.level=info) in project directory
• via gradle.properties in gradle user home (usually ~/.gradle)

For a system property, see -Dproperty=value accessible via System.getProperty. See this page about project/system properties and other ways to set them.

Java Gradle Plugin Development Plugin

Enable some validations:

• There is a plugin descriptor defined for the plugin.
• The plugin descriptor contains a valid implementation-class property.
• Each property getter or the corresponding field must be annotated with a property annotation like @InputFile and @OutputDirectory. Properties that don't participate in up-to-date checks should be annotated with @Internal.

Use the gradlePlugin{} block allows also:

• Generate the plugin descriptor (META-INF/my-plugin.properties).
• Configure the Maven publishing plugins to publish a Plugin Marker Artifact for each plugin.
• Easily use TestKit

About plugins DSL, put at the beginning of settings.gradle:

// See https://goo.gl/AmmZuy
pluginManagement {
    repositories {
        maven {
            url "file://${System.getProperty("user.home")}/.m2/repository"
        }
        gradlePluginPortal()
    }
}

Allow us to use:

plugins {
    id 'fr.pgreze.hello' version '1.0'
}

Instead of:

buildscript {
    dependencies {
        classpath 'fr.pgreze.hello:fr.pgreze.hello.gradle.plugin:0.1'
    }
}
apply plugin: 'fr.pgreze.hello'

But I'm too lazy to split each plugins from :jplugin in dedicated projects.

See this gradle example for an example of easy split.