Benefit from Groovy now, why when how — JFokus 2014

Guillaume Laforge   @glaforge Benefit from Groovy now, when, why
and how

Guillaume Laforge   @glaforge Benefit from Groovy now, when, why
and how By the way, you know there’s a Groovy User Group here in Stockholm? http://www.meetup.com/ Stockholm-Groovy-User- Group/

Guillaume Laforge Groovy project lead at . ! @glaforge
http://glaforge.appspot.com

Groovy in 5 minutes Introduction

Groovy… Open Source   alternative language   for the JVM

Groovy… Object-oriented, dynamic, with a functional flavor

Groovy… …also supports   static type checking &   static
compilation

million   downloads  in 2013

million   downloads  in 2013 3

million   downloads  in 2013 3 Twice as much as
in 2012!

Yup, we’re all using Groovy!

BIG USE CASES DSLs Apps Scripting Testing Customize

What for?

What for? for what kind of tasks

What for? Who? for what kind of tasks

What for? Who? for what kind of tasks projects, companies
using that pattern

Who? How? projects, companies using that pattern What for? for
what kind of tasks

Who? How? projects, companies using that pattern do it yourself
What for? for what kind of tasks

Task automation Build automation DevOps Scripting Case 1

@glaforge / #groovylang What for? Scripting: task automation ! •
Groovy is also a scripting language, you can easily… ! – run a Groovy script with the groovy command ! – @Grab & import third-party libraries •no need for a dedicated project or a build ﬁle •leverage the wealth of Ant tasks with the Groovy Ant builder ! – invoke other command-line tools !20

@glaforge / #groovylang Who? Scripting: task automation !21

@glaforge / #groovylang Who? Scripting: task automation !21 You or
anybody :-)

anybody :-) Or me for grepping through the logs to compute download stats

anybody :-) Or me for grepping through the logs to compute download stats Anyone who’s not a Bash guru!

anybody :-) Or me for grepping through the logs to compute download stats Anyone who’s not a Bash guru! Groovy team exports Confluence wiki to html, then transforms to AsciiDoc format

@glaforge / #groovylang How? Scripting: task automation !22 <html/> AsciiDoctor

@glaforge / #groovylang How? Scripting: task automation !22 Use HtmlCleaner
to clean the Confluence wiki HTML export <html/> AsciiDoctor

@glaforge / #groovylang How? Scripting: task automation !22 Use HtmlCleaner
to clean the Confluence wiki HTML export Transform the cleaned HTML into AsciiDoctor format <html/> AsciiDoctor

@glaforge / #groovylang How? Scripting: task automation !22 <html/> AsciiDoctor

@glaforge / #groovylang How? Scripting: task automation !23

@glaforge / #groovylang How? Scripting: task automation !23 This is
how you can grab a dependency…

@glaforge / #groovylang How? Scripting: task automation !23 This is
how you can grab a dependency… …and use the library right away, without a build file or IDE

@glaforge / #groovylang How? Scripting: task automation !24 Traverse the
file system easily

@glaforge / #groovylang How? Scripting: task automation !25 Execute external
commands

@glaforge / #groovylang How? Scripting: task automation !25 Execute external
commands Wait for the end of the process

@glaforge / #groovylang How? Scripting: task automation • Groovy’s APIs
feature – an Ant task scripting API to reuse all existing Ant tasks •ftp, ssh, ﬁle copying/moving… – a template engine •for generating ﬁles, source code – easy creation & parsing of XML or JSON payloads – Sql facility to simplifying accessing a JDBC compliant relational DB – exposing and accessing JMX beans !26

@glaforge / #groovylang How? Scripting: task automation !28 Use the
Groovy Markup Builder class to generate HTML or XML payloads

@glaforge / #groovylang How? Scripting: task automation !29 Use the
Ant Builder, reusing the Mail Ant task to send a build notification

@glaforge / #groovylang What for? Scripting: build automation ! •
Gradle is a powerful build automation solution – uses Groovy for its automation language ! • You can – build / package / deploy Java, Groovy, Scala, C/C++ projects – handle dependency management cleanly – deﬁne and enforce your own enterprise build conventions – extend Gradle declaratively and programmatically !30

@glaforge / #groovylang Who? Scripting: build automation !31

@glaforge / #groovylang How? Scripting: build automation !32

@glaforge / #groovylang How? Scripting: build automation !32 Use the
‘Java’ plugin

‘Java’ plugin Fetch your dependencies from Maven Central

‘Java’ plugin Fetch your dependencies from Maven Central Declare your dependencies and their scope

@glaforge / #groovylang How? Scripting: build automation !34 Declare and
use the ‘android’ plugin

@glaforge / #groovylang How? Scripting: build automation !35 Gradle plugins
can create their own declarative mini- language

@glaforge / #groovylang What for? Scripting: DevOps ! • More
Groovy-based initiatives around the DevOps theme ! • Goals – handle Amazon AWS conﬁguration, provisioning and deployments – talking with remote servers through SSH, and automating server conﬁguration, working with scp and more !36

@glaforge / #groovylang What for? Scripting: DevOps • Learn more:
! – http://slideshare.net/aestasit/groovy-dev-ops-in-the-cloud – sshoogr: a Groovy-based DSL for working with remote SSH servers – grammazon: a Groovy library and Gradle plugin for working with Amazon EC2 instances ! – https://github.com/danveloper/provisioning-gradle-plugin – a Gradle plugin for driving server provisioning through conﬁguration !37

@glaforge / #groovylang Who? Scripting: DevOps !38

@glaforge / #groovylang Who? Scripting: DevOps !38 Anyone who needs
to automate cloud deployments

@glaforge / #groovylang Who? Scripting: DevOps !38 Anyone who needs
to automate cloud deployments sshoogr & gramazon are from

@glaforge / #groovylang How? Scripting: DevOps with sshoogr !39

@glaforge / #groovylang How? Scripting: DevOps with sshoogr !39 Remote
execution

@glaforge / #groovylang How? Scripting: DevOps with sshoogr !39 Remote
execution SSH Secure copy

@glaforge / #groovylang How? Scripting: DevOps with gramazon Gradle plugin
!40

@glaforge / #groovylang How? Scripting: DevOps with gramazon Gradle plugin
!40 Start EC2 instances from your Gradle automation build

@glaforge / #groovylang How? Scripting: DevOps !41 https://github.com/aestasit

@glaforge / #groovylang How? Scripting: DevOps with Provisioning Gradle plugin
!42

!42 Import and apply the Provisioning plugin for Gradle

!43

!43 Virtual box configuration

!43 Virtual box configuration Network configuration

!44

!44 Disk partitioning definition

!45

!45 Packages to be installed

!46

!46 Post installation commands

! ! • Checkout the Provisioning Gradle plugin from Dan Woods: ! – https://github.com/danveloper/provisioning-gradle-plugin !47

More readable & expressive tests Testing Case 2

@glaforge / #groovylang What for? Testing: More readable & expressive
tests ! • Groovy has a malleable and streamlined syntax ! • Makes it nice for creating libraries and frameworks   with readable and expressive APIs !49

@glaforge / #groovylang Who? Testing: More readable & expressive tests
! • Many companies started integrating Groovy   in their projects through testing,   before any line of Groovy code in production ! • Beneﬁt – easier to add, evolve and maintain test cases !50

@glaforge / #groovylang How? Testing: More readable & expressive tests
! • We’ll have a look at: ! – the Spock testing framework – the Geb web integration testing framework !51

I’m Spock...

I’m Spock... ...the Spock testing framework

@glaforge / #groovylang How? Testing: Spock test framework !53

@glaforge / #groovylang How? Testing: Spock test framework !53 Wiki-like
notation for defining data driven tests

@glaforge / #groovylang How? Testing: Spock test framework !54

Define the mock interactions

Define the mock interactions Possible to define cardinality, matching any
number of parameter, or arbitrary method name

@glaforge / #groovylang How? Testing: Geb web integration tests !57

An HtmlUnit, FireFox or Chrome browser

An HtmlUnit, FireFox or Chrome browser Drive the browser to a certain URL

An HtmlUnit, FireFox or Chrome browser Drive the browser to a certain URL Assert the title contains the text

An HtmlUnit, FireFox or Chrome browser Drive the browser to a certain URL Assert the title contains the text Fill in a form, click the button to send it

@glaforge / #groovylang How? Testing: Geb web integration tests with
Spock !58

Spock !58 With page objects

Spock !58 With page objects BDD style: given/when/then

Spock !58 With page objects BDD style: given/when/then Wait for slow loading pages

Extension points Configuration Customizing Case 3

@glaforge / #groovylang What for? Customizing: extension, configuration, plugins !
• You need to… ! – customize an application for a particular customer – conﬁgure an application for a particular environment – create / update / externalize business rules – create plugins for extending a platform !60

@glaforge / #groovylang Who? Customizing: extension, configuration, plugins !61

@glaforge / #groovylang Who? Customizing: extension, configuration, plugins !61 Continuous
Integration server

Integration server Internet of Things

Integration server Internet of Things Second-generation wiki

@glaforge / #groovylang How? Customizing: extension, configuration, plugins ! •
Jenkins provides two Groovy plugins: ! – the Groovy plugin  https://wiki.jenkins-ci.org/display/JENKINS/Groovy+plugin •execute arbitrary Groovy scripts as Jenkins jobs ! – the Groovy postbuild plugin  https://wiki.jenkins-ci.org/display/JENKINS/Groovy+Postbuild+Plugin •set build outcome, display badges, info or error messages, once a build completed !62

@glaforge / #groovylang How? Customizing: extension, configuration, plugins !63

Home automation in the era   of the Internet of Things ! • Built-in IDE and simulator allow you to automate   all your devices of your home with Groovy scripts  https://support.smartthings.com/entries/21603015-Introduction-to-Writing-SmartApps ! • Groovy supports allows to • set preferences, subscribe to events, set timers, handle events, send notiﬁcations, access people’s presence, consume external services… !64

XWiki is a second-generation wiki  http://www.xwiki.org/  (XWiki case study: http://bit.ly/xwiki-cs) • not just content, but programmable • a platform for building your own apps • extensible with plugins and macros ! • You can create your own plugins and macros in Groovy to extend the wiki, and add dynamic content !66

@glaforge / #groovylang How? Customizing: extension, configuration, plugins !67 A
wiki user with programming rights can add this Groovy script in a page

@glaforge / #groovylang How? Customizing: extension, configuration, plugins !67 A
wiki user with programming rights can add this Groovy script in a page Uses Groovy’s handy JSON support

@glaforge / #groovylang How? Customizing: extension, configuration, plugins • What
Groovy also brings to the table: ! • a rich API for integrating and embedding Groovy in your app • GroovyShell, Binding, customizers… ! • dedicated conﬁguration API (ConﬁgSlurper) with a special « builder » syntax with a hierarchical data structure ! • a JMX bean & JMX builder for interacting with   and exposing JMX services !68

Expressive business rules Domain-Specific Language Case 4

@glaforge / #groovylang What for? Domain-Specific Languages: business rules •
The goal of Groovy Domain-Speciﬁc Languages: • beyond just integrating Groovy scripts and classes: create a dedicated mini-language modeling your business • less technical boilerplate code, focus on the business semantics • write almost plain English-like sentences ! • Groovy has… • a succint, ﬂexible & malleable syntax • both dynamic and compile-time metaprogramming capabilities • operator overloading !70

@glaforge / #groovylang Who? Domain-Specific Languages: business rules !71

@glaforge / #groovylang Who? Domain-Specific Languages: business rules !71 US
Fortune 500 insurance actuaries write risk calculation rules in Groovy

Fortune 500 insurance actuaries write risk calculation rules in Groovy EPO built a data flow language atop Groovy to extract / transform / route patents across patent offices

Fortune 500 insurance actuaries write risk calculation rules in Groovy EPO built a data flow language atop Groovy to extract / transform / route patents across patent offices 1 billion € worth of loan granted through Hypoport’s financial platform Groovy decision rules

Fortune 500 insurance actuaries write risk calculation rules in Groovy EPO built a data flow language atop Groovy to extract / transform / route patents across patent offices 1 billion € worth of loan granted through Hypoport’s financial platform Groovy decision rules Customize experience of travel and hotel reservation with Groovy scripts and templates

Fortune 500 insurance actuaries write risk calculation rules in Groovy EPO built a data flow language atop Groovy to extract / transform / route patents across patent offices 1 billion € worth of loan granted through Hypoport’s financial platform Groovy decision rules Customize experience of travel and hotel reservation with Groovy scripts and templates Case study: http://bit.ly/epo-cs

@glaforge / #groovylang How? Domain-Specific Languages: business rules • Groovy
uses BigDecimal by default for floating point • you can, of course, specify floats or doubles if needed • important for financial calculations w/ exact arithmetics !72

uses BigDecimal by default for floating point • you can, of course, specify floats or doubles if needed • important for financial calculations w/ exact arithmetics !72 Which formula would you rather maintain?

uses BigDecimal by default for floating point • you can, of course, specify floats or doubles if needed • important for financial calculations w/ exact arithmetics !72 Which formula would you rather maintain? Operator overloading

lets you create your own control   structures with closures !73

@glaforge / #groovylang How? Domain-Specific Languages: business rules • A
Groovy-based DSL developed at the  Liverpool School of Tropical Medicine  to study antimalarial drug resistance !74

@glaforge / #groovylang How? Domain-Specific Languages: business rules • A
Groovy-based DSL developed at the  Liverpool School of Tropical Medicine  to study antimalarial drug resistance !74 Paper: http://bit.ly/ronald-dsl

Adding properties to numbers through runtime meta-programming

Adding properties to numbers through runtime meta-programming Groovy « command
chains »: syntax convention for dropping parens & dots for natural-language-like sentences

Web & reactive apps Desktop apps Full blown apps Case
5

@glaforge / #groovylang Groovy ecosystem • The Groovy ecosystem is
rich of tools, frameworks, and libraries ! • For web development, you can use – the mainstream Grails web stack, powered by Spring and Groovy – the newcomer Ratpack, a lightweight toolkit on top of Netty – or Spring Boot, an opinionated & Groovy-friendly take on Spring ! • For desktop applications, you can use Griffon – which supports different view toolkits such as GroovyFX, Swing, Pivot… !77

@glaforge / #groovylang What for? Full blown apps: the Grails
web framework ! • Grails is a full web stack for the JVM – based on Groovy and Spring – can interact with relational databases through Hibernate or through any NoSQL datastore with Spring Data, with the GORM mapping layer – follows the Convention over Conﬁguration paradigm – lets you see changes live with hot reloading – advanced REST and Async support – built-in view technology (GSPs) with taglibs !78

@glaforge / #groovylang Who? Full blown apps: the Grails web
framework !79

framework !79 Created the Open Source Asgard web interface for application deployments and cloud management in Amazon Web Services

framework !79 Created the Open Source Asgard web interface for application deployments and cloud management in Amazon Web Services LinkedIn uses Grails for their commercial portals, for recruiters, companies searching for profiles…

framework !79 Created the Open Source Asgard web interface for application deployments and cloud management in Amazon Web Services LinkedIn uses Grails for their commercial portals, for recruiters, companies searching for profiles… Many web frontends from the Sky network serving a few hundred millions page views a month

framework !79 Created the Open Source Asgard web interface for application deployments and cloud management in Amazon Web Services LinkedIn uses Grails for their commercial portals, for recruiters, companies searching for profiles… Many web frontends from the Sky network serving a few hundred millions page views a month Wired’s product review section is powered by Grails

@glaforge / #groovylang How? Full blown apps: the Grails web
framework !80

@glaforge / #groovylang How? Full blown apps: the Grails web
framework !80 Too hard to cover Grails in a couple slides, just go download it now! :-)

Groovy’s cool :-) Summary

@glaforge / #groovylang Java’s best friend • Java derived syntax
–Flat learning curve –Easy to learn • But goes beyond Java –Concise, expressive, readable –Fit for Domain-Speciﬁc Languages • Seamless & transparent Java integration –Mix & match Groovy & Java classes (joint compil.) –No language barrier to cross !82

@glaforge / #groovylang Groovy’s nature ! • Object oriented dynamic
language... ! • But... – as type safe as you want it — static type checking – as fast as you need it — static compilation – as functional as you make it — closures... !83

@glaforge / #groovylang Groovy use cases • Scripting tasks, build
automation, DevOps • Extension points for customizing / conﬁguring apps • More readable and expressive tests • Business languages & Domain-Speciﬁc Languages • Full blown apps – for the web with Grails, Ratpack, Gaelyk – for web reactive programming with Reactor – for desktop with Griffon !84

…for your attention! Thanks

Slides will be available at: speackerdeck.com/ glaforge Q & A

Benefit from Groovy now, why when how — JFokus ...

Benefit from Groovy now, why when how — JFokus 2014

Transcript