#jbcn2016 JBCN 2016 © Schalk W. Cronjé1

GRADLE IN 45MINSchalk Cronjé

ABOUT ME

Email:

Twitter / Ello : @ysb33r

ysb33r@gmail.com

Gradle plugins authored/contributed to: VFS, Asciidoctor,JRuby family (base, jar, war etc.), GnuMake, Doxygen

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GET YOUR DAILY GRADLE DOSE

@DailyGradle

#gradleTip

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SDKMANManages parallel version of multiple SDKs

Mostly for (but not limited to) JVM-related systems

Windows users can use Posh-GVM (Powershell)

Windows 10 Bash ??

curl -s http://get.sdkman.io | bash

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SDKMAN

SdkMan:

Posh-GVM:

@sdkmanager

http://sdkman.io

https://github.com/�ofreud/posh-gvm

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GRADLEA next generation build-and-deploy pipeline

tool

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MOST TRIVIAL JAVA PROJECTapply plugin: 'java'

Will look for sources under src/main/java

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JAVA PROJECTrepositories { jcenter() }

apply plugin : 'java'

dependencies { testCompile 'junit:junit:4.1' }

GRADLE DEPENDENCY MANAGEMENTEasy to use

Flexible to con�gure for exceptions

Uses dependencies closure

First word on line is usually name of a con�guration.

Con�gurations are usually supplied by plugins.

Dependencies are downloaded from repositories

Maven coordinates are used as format

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GRADLE REPOSITORIES

Speci�ed within a repositories closure

Processed in listed order to look for dependencies

jcenter() preferred open-source repo.

mavenLocal(), mavenCentral(), maven {}

Ivy repositories via ivy {}

Flat-directory repositories via flatDir

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GRADLE REPOSITORIESrepositories { jcenter() mavenCentral() maven { url "https://plugins.gradle.org/m2/" } }

repositories { ivy { url 'file://path/to/repo' layout 'pattern', { artifact '[module]/[revision]/[artifact](.[ext])' ivy '[module]/[revision]/ivy.xml' } } }

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GRADLE DSLUnderlying language is Groovy

You don’t need to be a Groovy expert to be a Gradle poweruser

Groovy doesn’t need ; in most cases

Groovy does more with less punctuation, making it an idealchoice for a DSL

In most cases lines that do not end on an operator isconsidered a completed statement.

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GROOVY VS JAVA

In Groovy:

All class members are public by default

No need to create getters/setters for public �elds

Both static & dynamic typing supported

def means Object

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CALLING METHODSclass Foo { void bar( def a,def b ) {} }

def foo = new Foo()

foo.bar( '123',456 ) foo.bar '123', 456

foo.with { bar '123', 456}

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CALLING METHODS WITH CLOSURESclass Foo { void bar( def a,Closure b ) {}}

def foo = new Foo()

foo.bar( '123',{ println it } )

foo.bar ('123') { println it }

foo.bar '123', { println it }

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MAPS IN GROOVY

Hashmaps in Groovy are simple to use

def myMap = [ plugin : 'java' ]

Maps are easy to pass inline to functions

project.apply( plugin : 'java' )

Which in Gradle can become

apply plugin : 'java'

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LISTS IN GROOVY

Lists in Groovy are simple too

def myList = [ 'clone', ''http://github.com/ysb33r/GradleLectures' ]

This makes it possible for Gradle to do

args 'clone', 'http://github.com/ysb33r/GradleLectures'

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CLOSURE DELEGATION IN GROOVY

When a symbol cannot be resolved within a closure,Groovy will look elsewhere

In Groovy speak this is called a Delegate.

This can be programmatically controlled via theClosure.delegate property.

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CLOSURE DELEGATION IN GROOVYclass Foo { def target }

class Bar { Foo foo = new Foo() void doSomething( Closure c ) { c.delegate = foo c() } }

Bar bar = new Bar() bar.doSomething { target = 10 }

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MORE CLOSURE MAGIC

If a Groovy class has a method 'call(Closure)`, the object canbe passed a closure directly.

class Foo { def call( Closure c) { /* ... */ } }

Foo foo = new Foo() foo {

println 'Hello, world'

}

// This avoids ugly syntax foo.call({ println 'Hello, world' })

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CLOSURE DELEGATION IN GRADLE

In most cases the delegation will be entity the closure ispassed to.

Will also look at the Project and ext objects.

The Closure.delegate property allows plugin writersability to create beautiful DSLs

task runSomething(type : Exec ) { cmdline 'git' }

is roughly the equivalent of

ExecTask runSomething = new ExecTask() runSomething.cmdline( 'git' )

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GRADLE TASKSCan be based upon a task type

task runSomething ( type : Exec ) {

command 'git'

args 'clone', 'https://bitbucket.com/ysb33r/GradleWorkshop'

}

Can be free-form

task hellowWorld << {

println 'Hello, world'

}

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GRADLE TASKS : CONFIGURATION VS ACTION

Use of << {} adds action to be executed

Tasks supplied by plugin will have default actions

Use of {} con�gures a task

BUILDSCRIPTThe buildscript closure is special

It tells Gradle what to load into the classpath beforeevaluating the script itself.

It also tells it where to look for those dependencies.

Even though Gradle 2.1 has added a new way of addingexternal plugins, buildscript are much more �exible.

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EXTENSIONS

Extensions are global con�guration blocks added byplugins.

Example: The jruby-gradle-base plugin will add ajruby block.

apply plugin: 'com.github.jruby-gradle.base'

jruby { defaultVersion = '1.7.11' }

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GRADLE COMMAND-LINEgradle -v gradle -h gradle tasks gradle tasks --info

GRADLE WRAPPERUse wrapper where possible:

Eliminates need to install Gradle in order to build project

Leads to more reproducible builds

gradle wrapper --wrapper-version 2.12

./gradlew tasks

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EXECUTING TASKS./gradlew <taskName1> <taskName2> ...

./gradlew build

DEPENDENCIESExamine dependencies involved with various con�gurations

./gradlew dependencies

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SUPPORT FOR OTHER JVM LANGUAGES

GROOVY PROJECTrepositories { jcenter() }

apply plugin : 'groovy'

dependencies { compile 'org.codehaus.groovy:groovy-all:2.4.3'

testCompile ('org.spockframework:spock-core:1.0-groovy-2.4') { exclude module : 'groovy-all' } }

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SCALA PROJECTrepositories { jcenter() }

apply plugin : 'scala'

dependencies { compile 'org.scala-lang:scala-library:2.11.8' }

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BUILDING KOTLINplugins { id "com.zoltu.kotlin" version "1.0.1" }

dependencies { compile "org.jetbrains.kotlin:kotlin-stdlib:1.0.1-1"

}

RUNNING JRUBYplugins {

id 'com.github.jruby-gradle.base' version '1.2.1'

}

import com.github.jrubygradle.JRubyExec

dependencies {

jrubyExec "rubygems:colorize:0.7.7"

}

task printSomePrettyOutputPlease(type: JRubyExec) {

description "Execute our nice local print-script.rb"

script "${projectDir}/print-script.rb"

}

(Example from JRuby-Gradle project)

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OTHER LANGUAGESC++ / C / ASM / Resources (built-in)

Clojure (plugin)

Frege (plugin)

Golang (plugin)

Gosu (plugin)

Ceyon (plugin)

Mirah (plugin)

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SUPPORT FOR OTHER BUILDSYSTEMSANT (built-in)

GNU Make

MSBuild / xBuild

Grunt, Gulp

Anything else craftable via Exec or JavaExec task

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BUILDING DOCUMENTATION

Javadoc, Groovydoc, Scaladoc (built-in)

Doxygen (C, C++) (plugin)

Markdown (plugin)

Asciidoctor (plugin)

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BUILDING WITH ASCIIDOCTORplugins { id 'org.asciidoctor.convert' version '1.5.2' }

BUILDING WITH ASCIIDOCTORrepositories { jcenter() }

asciidoctor { sources { include 'example.adoc' }

backends 'html5'

}

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PUBLISHING

Built-in to Maven, Ivy

Metadata publishing for native projects still lacking

Various plugins for AWS and other cloud storage

Plain old copies to FTP, SFTP etc.

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MORE SUPPORT…

Of�cial buildsystem for Android

Docker

Hadoop

TOUR DE FORCE

Build a distributable application packaged as as ZIP

Runnable via shell script or batch �le

Contains classes written Java, Groovy & Kotlin source

Test source code with Spock Framework

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TOUR DE FORCEplugins { id 'java' id 'groovy' id 'com.zoltu.kotlin' version '1.0.1' id 'application' }

repositories { jcenter() }

dependencies { compile 'org.codehaus.groovy:groovy-all:2.4.3' compile 'org.jetbrains.kotlin:kotlin-stdlib:1.0.1-1' testCompile 'org.spockframework:spock-core:1.0-groovy-2.4' }

version = '1.0' mainClassName = "gradle.workshop.HelloJava"

compileGroovy.dependsOn compileKotlin

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ENDGAMEGradle is breaking new ground

Ever improving native support

Continuous performance improvements

Go �nd some more plugins at https://plugins.gradle.org

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ABOUT THIS PRESENTATIONWritten in Asciidoctor

Styled by asciidoctor-revealjs extension

Built using:

Gradle

gradle-asciidoctor-plugin

gradle-vfs-plugin

Code snippets tested as part of build

Source code:https://github.com/ysb33r/GradleLectures/tree/Jbcn2016

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WRITING PLUGINS?

https://leanpub.com/b/idiomaticgradle

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THANK YOUEmail:

Twitter / Ello : @ysb33r

#idiomaticgradle

ysb33r@gmail.com

(Just in-case you need a buildtool consultant)

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MIGRATIONS

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ANT TO GRADLE

Re�ect Ant Build into Gradle

ant.importBuild('build.xml')

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MAVEN TO GRADLE

Go to directory where pom.xml is and type

gradle init --type pom

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USEFUL STUFF

PUBLISHING VIA VFSplugins { id "org.ysb33r.vfs" version "1.0" }

task publishToWebserver << {

vfs { cp "${buildDir}/website", "ftp://${username}:${password}@int.someserver.com/var/www", recursive : true, overwrite : true } }