Gradle

Gradle: Build Automation for the JVM, Android, and C/C++
Gradle | Gradle Features

Command-Line Interface

# info and debug log
gradle -i task
gradle -d task

# show project properties
gradle properties

Gradle Release Notes
Gradle User Guide
Gradle | Gradle Tutorials and Guides
Gradle User Guide 中文版 of older version

An introduction to Gradle for complete beginners - Android Authority
Building C++ applications and libraries
Building Java & JVM projects

Gradle in 60 Seconds
Using Gradle Build Variants - Tuts+ Code Tutorial
The Ins and Outs of Gradle

Trainings | Gradle Enterprise
Blog | Gradle Enterprise
Dependency Management with Gradle Part 1 - Fundamentals | Gradle Enterprise
Build Best Practicess | Gradle Enterprise
Build performances | Gradle Enterprise

CircleCI cache key over many files – Chris Banes – Medium

The one Gradle trick that supersedes all the others generate scans for debugging and support

DSL

Gradle DSL Version

The Power of Gradle Kotlin DSL - Kotlin Expertise Blog
Gradle Kotlin DSL Primer
A Groovy Build Script Primer

Gradle Kotlin DSL 1.0
The Road to Gradle Script Kotlin 1.0
Kotlin Meets Gradle
gradle/kotlin-dsl: Kotlin language support for Gradle build scripts

Migrating build logic from Groovy to Kotlin
Migrating Android build scripts from Groovy to Kotlin DSL
The New Way of Writing Build Gradle with Kotlin DSL

Anti-pattern

// don't use this
apply plugin: 'kotlin'

// use this
plugins {
    kotlin("jvm") version "1.3.21"
}

Examples

gradle/subprojects/docs/src/samples at master · gradle/gradle
kotlin-dsl/samples at master · gradle/kotlin-dsl

JetBrains/kotlin: The Kotlin Programming Language Kotlin project uses Kotlin DSL

Groovy vs Kotlin

I prefer Kotlin over Groovy:

• Kotlin is more modern, has more potential and more worthy to learn than Groovy
• Parentheses for function invocation is optional in Groovy, making it even harder to distingush between setting field or calling function

repositories {
    jcenter()
}

configurations {
    ktlint
}

dependencies {
    ktlint "com.github.shyiko:ktlint:0.29.0"
}

task ktlint(type: JavaExec, group: "verification") {
    description = "Check Kotlin code style."
    classpath = configurations.ktlint
    main = "com.github.shyiko.ktlint.Main"
    args "src/**/*.kt"
}

task ktlintFormat(type: JavaExec, group: "formatting") {
    description = "Fix Kotlin code style deviations."
    classpath = configurations.ktlint
    main = "com.github.shyiko.ktlint.Main"
    args "-F", "src/**/*.kt"
}

allprojects {
    apply from: "$rootDir/ktlint.gradle"
}

Plugins

Gradle - Plugins

Wrapper

The Gradle Wrapper

A local copy of Gradle can be downloaded in ./gradle/, a wrapper gradlew will be created. This allows for version controlling Gradle tool and self-contained build environment.

# with gradle installed on host
gradle init --dsl kotlin
gradle wraper --gradle-version=5.3.1

# even better using gradle Docker image
docker run --rm -u $(id -u):$(id -g) \
   -v "$PWD":/home/gradle/project -w /home/gradle/project \
   gradle gradle init --dsl kotlin
docker run --rm -u $(id -u):$(id -g) \
   -v "$PWD":/home/gradle/project -w /home/gradle/project \
   gradle gradle wrapper --gradle-version=5.3.1

gradle - Docker Hub

Lifecycle

Build Lifecycle
Understanding Gradle: the Build Lifecycle – ProAndroidDev
Cédric Champeau's blog: Gradle myth busting: lifecycle

Tasks

# show tasks
gradle tasks
# also show tasks not in task group
gradle tasks --all

# filter by task group
gradle tasks --group="build setup"

# show details of task
gradle -q help --task <task>

# upload build scan to https://scans.gradle.com/
# https://gradle.com/build-scans/
gradle --scan <task>

Milti project

# list sub-projects, displayed in a hierarchy
gradle projects

Docker plugins

palantir/gradle-docker: a Gradle plugin for orchestrating docker builds and pushes.
Gradle Docker Plugin User Guide & Examples
bmuschko/gradle-docker-plugin: Gradle plugin for managing Docker images and containers.
avast/gradle-docker-compose-plugin: Simplifies usage of Docker Compose for integration testing in Gradle environment.

Comparison

Gradle vs Maven Comparison
Gradle vs. Maven - DZone Java
Java Build Tools: Ant vs Maven vs Gradle | Technology Conversations

Android adoption

New Build System - Android Tools Project Site
Build System Overview | Android Developers