migrating 25k lines of ant scripting to gradle
Post on 11-Apr-2017
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Who is this guy?
We will consult these 3 experts
Linus Torvalds
creator of Linux & Git
We will consult these 3 experts
Linus Torvalds Mark Reinhold
creator of Linux & Git Java's chief architect
We will consult these 3 experts
Linus Torvalds Mark Reinhold Louis van Gaal
creator of Linux & Git Java's chief architect manager ofManchester United
We will consult these 3 experts
Linus Torvalds Mark Reinhold Louis van Gaal
creator of Linux & Git Java's chief architect former manager ofManchester United
Changes inrequirements
Changes in requirementsPast
compiling
packaging
Changes in requirementsPresent
one project, multiple programming languages
compiling
running automated tests
packaging
integrating code as early as possible
deploying software to TAP
Defining builds inXML
XMLLet's start by being nice:
excels at expressing hierarchical data
XMLLet's start by being nice:
excels at expressing hierarchical data
but...build scripting logic doesn't easily fit a hierarchy
often it consists of conditional and repeating logic
which can be expressed more concisely in a programming
language
What does Linus think of XML?
What does Linus think of XML?
( )
XML is crap. Really. There are no excuses.
XML is nasty to parse for humans, and it's a
disaster to parse even for computers. There's
just no reason for that horrible crap to exist.
https://plus.google.com/+LinusTorvalds/posts/X2XVf9Q7MfV
Build tools:head to head
Ant vs. Maven according to Mark
Ant vs. Maven according to Mark
( )
What's the difference between Ant and
Maven?
https://www.parleys.com/tutorial/devoxx-fireside-chat
Ant vs. Maven according to Mark
( )
What's the difference between Ant and
Maven? The creator of Ant has apologized.
https://www.parleys.com/tutorial/devoxx-fireside-chat
Build tools head-to-headAnt Maven Gradle
Build tools head-to-headAnt Maven Gradle
build script format XML XML Groovy / DSL
Build tools head-to-headAnt Maven Gradle
build script format XML XML Groovy / DSL
dependencies with Ivy built-in built-in
Build tools head-to-headAnt Maven Gradle
build script format XML XML Groovy / DSL
dependencies with Ivy built-in built-in
multi-module builds complex simple simple
Build tools head-to-headAnt Maven Gradle
build script format XML XML Groovy / DSL
dependencies with Ivy built-in built-in
multi-module builds complex simple simple
pre-defined structure absent present present
Build tools head-to-headAnt Maven Gradle
build script format XML XML Groovy / DSL
dependencies with Ivy built-in built-in
multi-module builds complex simple simple
pre-defined structure absent present present
custom structure n/a complex simple
Build tools head-to-headAnt Maven Gradle
build script format XML XML Groovy / DSL
dependencies with Ivy built-in built-in
multi-module builds complex simple simple
pre-defined structure absent present present
custom structure n/a complex simple
verbosity high average low
Build tools head-to-headAnt Maven Gradle
build script format XML XML Groovy / DSL
dependencies with Ivy built-in built-in
multi-module builds complex simple simple
pre-defined structure absent present present
custom structure n/a complex simple
verbosity high average low
learning curve shallow steep average
Build tools head-to-headAnt Maven Gradle
build script format XML XML Groovy / DSL
dependencies with Ivy built-in built-in
multi-module builds complex simple simple
pre-defined structure absent present present
custom structure n/a complex simple
verbosity high average low
learning curve shallow steep average
build order depends-on lifecycles directed acyclic graph
Gradle at NS(Dutch Railways)
Gradle at NS (Dutch Railways)not at all a 'greenfield project'!
1 million lines of code
over 25,000 lines of Ant scripting
30 software developers
system behaves like a monolith
Migration strategy
Migration strategydivide the project into components according to
functionality
start Gradling at a small, isolated part
focus on code that is used regularly (i.e. on a daily basis)
Migration strategydivide the project into components according to
functionality
start Gradling at a small, isolated part
focus on code that is used regularly (i.e. on a daily basis)
verify after each step that:
results are exactly the same as before
no problems occur in existing Ant code
Migration strategydivide the project into components according to
functionality
start Gradling at a small, isolated part
focus on code that is used regularly (i.e. on a daily basis)
verify after each step that:
results are exactly the same as before
no problems occur in existing Ant code
don't fool yourself: not every single line of Ant code should
be replaced
Ant projects are 'first class citizens'
Challengesdependency spaghetti
collaboration with existing Ant code
continuous integration & delivery
Migration resulta component's responsibility has become clearer
a build will only run if the particular component has
changed
run unit test in parallel (Gradle decides when)
dependencies behave transitively
Migration result (lines of code)Language Lines of code (before) Lines of code (after)
Ant over 25,000 about 15,000
Gradle 0 1,232
What does Louis think of migrating all Antcode?
What does Louis think of migrating all Antcode?
( )
In the Netherlands they say: "That is another
cook."
https://youtu.be/x-QRqOndbzw
Wrap-up
Wrap-up
Wrap-upAnt & Maven:
require hard-to-maintain code
the purpose of a code fragment is not clearly evident
Wrap-upAnt & Maven:
require hard-to-maintain code
the purpose of a code fragment is not clearly evident
often fail to address changing requirements
rely heavily on XML
Wrap-upAnt & Maven:
require hard-to-maintain code
the purpose of a code fragment is not clearly evident
often fail to address changing requirements
rely heavily on XML
Gradle is a better alternative
Wrap-up (2)Gradle offers structure and flexibility
tries to combine the power of Ant and Maven
integrates with (almost) anything
Wrap-up (3)So no drawbacks whatsoever?
Wrap-up (3)So no drawbacks whatsoever?
Gradle spends a lot of time on configuration parsing (but
this has steadily improved in the past year)
developers need to get used to it
migrating existing scripting is a lot of work
Should my project use Gradle?A brand-new project?
Should my project use Gradle?A brand-new project?
just do it
Should my project use Gradle?A brand-new project?
just do it
do it RIGHT NOW
Should my project use Gradle?An existing project?
Should my project use Gradle?An existing project?
Will you benefit from Gradles key features? (better
performance, maintainability, less verbose, ...)
Should my project use Gradle?An existing project?
Will you benefit from Gradles key features? (better
performance, maintainability, less verbose, ...)
Any technical debt to solve?
Should my project use Gradle?An existing project?
Will you benefit from Gradles key features? (better
performance, maintainability, less verbose, ...)
Any technical debt to solve?
use an artifact repository and remove duplicates
divide your project into multiple components
define a clear structure in your build logic
Any questions?
Further reading"Why Build Your Java Projects with Gradle Rather than Ant
or Maven?"
by Benjamin Muschko( )
Gradle User Guide( )
Gradle Build Language Reference( )
http://www.drdobbs.com/jvm/why-build-your-java-projects-with-gradle/240168608
http://gradle.org/docs/current/userguide/userguide.html
http://gradle.org/docs/current/dsl/index.html
Thank you :)
You can contact me at:
@hannotify
hanno.embregts@infosupport.com
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