Experience report from porting an Ant and a Maven project to Gradle. Held at javaBin 5. October 2011. The slides give an overview of the content.

1. gradle
Thor Åge Eldby
Monday, November 21, 2011 1

2. Thor Åge Eldby
@thoraageeldby
Arktekk
2
Monday, November 21, 2011 2
2.5 år in Arktekk
16 år in system development

3. Build Systems
make
sbt
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Make, batch-files (COS,Steinar Haugen,Kenneth Stigen)
ant -> can compile java
maven -> conventions, dependencies
sbt and now gradle

4. What: Repeatable
ear ear ear ear
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Independent from host, platform, time
All information in build scripts
•How
•What
•Externals
-Ant

5. What: Flexible
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Possible to build
Simple
-Maven, Ant

6. What: Readable
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Not a black box
Diffable
GUI is not

7. What: Conventions
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Recognisable
Structures
Commands
-Ant

8. 8
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Repeatable
Flexible - Groovy (and ant) building DSL
Readable
Conventions - Follows maven structure partly
Systemised, programmable ant

9. Simple Example
apply plugin: 'java'
repositories {
mavenCentral()
}
dependencies {
compile 'com.google.guava:guava:r08'
}
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Needed to compile java code into jar
Build DSL
Script blocks (many)

10. Plugin
apply plugin: 'java'
repositories {
mavenCentral()
}
dependencies {
compile 'com.google.guava:guava:r08'
}
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Interpreted script

11. Dependencies
apply plugin: 'java'
repositories {
mavenCentral()
}
dependencies {
compile 'com.google.guava:guava:r08'
}
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Configuration like scope in maven
... and classpath in ant

12. Dependencies
apply plugin: 'java'
repositories {
dependencies {
mavenCentral()
compile project(':common')
}
}
dependencies {
compile 'com.google.guava:guava:r08'
}
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Configuration like scope in maven
... and classpath in ant

13. Dependencies
apply plugin: 'java'
repositories {
dependencies {
dependencies {
mavenCentral()
testCompile group: 'junit', name: 'junit',
compile project(':common')
}
version: '4.+'
}
} dependencies {
compile 'com.google.guava:guava:r08'
}
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Configuration like scope in maven
... and classpath in ant

14. Dependencies
apply plugin: 'java'
dependencies {
repositories {
dependencies {
dependencies {
compile('org.hibernate:hibernate:3.0.5') {
mavenCentral()
testCompile group: 'junit', name: 'junit',
compile project(':common')
transitive = false
}
version: '4.+'
} }
} dependencies {
}
compile 'com.google.guava:guava:r08'
}
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Configuration like scope in maven
... and classpath in ant

15. Dependencies
apply plugin: 'java'
dependencies {
repositories {
dependencies {
dependencies {
compile('org.hibernate:hibernate:3.0.5') {
runtime files('libs/a.jar', 'libs/b.jar')
mavenCentral()
testCompile group: 'junit', name: 'junit',
runtime fileTree(dir: 'libs',
compile project(':common')
transitive = false
}
version: '4.+'
} } include: '*.jar')
} dependencies {
}
compile 'com.google.guava:guava:r08'
}
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Configuration like scope in maven
... and classpath in ant

16. Dependencies
apply plugin: 'java'
dependencies {
repositories {
dependencies {
dependencies {
compile('org.hibernate:hibernate:3.0.5') {
testCompile('org.testng:testng:6.2.1') {
runtime files('libs/a.jar', 'libs/b.jar')
mavenCentral()
testCompile group: 'junit', name: 'junit',
runtime fileTree(dir: 'libs',
compile project(':common')
transitive = false
exclude module: 'guice'
}
version: '4.+'
} } include: '*.jar')
} dependencies {
}
compile 'com.google.guava:guava:r08'
}
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Configuration like scope in maven
... and classpath in ant

17. Repositories
apply plugin: 'java'
repositories {
mavenCentral()
}
dependencies {
compile 'com.google.guava:guava:r08'
}
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18. Repositories
apply plugin: 'java'
repositories {
repositories {
mavenCentral()
mavenRepo urls: "http://repo.my.com/maven2"
}
}
dependencies {
compile 'com.google.guava:guava:r08'
}
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19. Repositories
apply plugin: 'java'
repositories {
repositories {
mavenCentral()
mavenLocal()
mavenRepo urls: "http://repo.my.com/maven2"
}
}
dependencies {
compile 'com.google.guava:guava:r08'
}
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20. Repositories
apply plugin: 'java'
repositories {
repositories {
repositories {
flatDir {
mavenCentral()
mavenLocal()
mavenRepo urls: "http://repo.my.com/maven2"
dirs 'lib'
}
} }
dependencies {
}
compile 'com.google.guava:guava:r08'
}
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21. Repositories
apply plugin: 'java'
repositories {
repositories {
repositories {
ivy {
repositories {
flatDir {
mavenCentral()
url "http://repo.mycompany.com/repo"
mavenLocal()
mavenRepo urls: "http://repo.my.com/maven2"
dirs 'lib'
}
layout "maven"
} }
}
dependencies {
}
}
compile 'com.google.guava:guava:r08'
}
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22. Coding It
apply plugin: 'java'
repositories {
mavenCentral()
}
dependencies {
compile 'com.google.guava:guava:r08'
}
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Tasks (like ant targets)
•Depends on
Repositories
•Uses maven
Configurations (like maven scopes)
Building simple example without plugins
Compile java and jar it
Keeping out testing and all the other stuff
Prefer functions over tasks

23. Coding It
apply plugin: 'java'
repositories {
mavenCentral()
}
dependencies {
compile 'com.google.guava:guava:r08'
}
13
Monday, November 21, 2011 13
Tasks (like ant targets)
•Depends on
Repositories
•Uses maven
Configurations (like maven scopes)
Building simple example without plugins
Compile java and jar it
Keeping out testing and all the other stuff
Prefer functions over tasks

24. Multi Project
myproject
api
common
web
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25. Multi Project
settings.gradle
include 'common', 'api', 'web'
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Settings object - Including multiprojects

26. Multi Project
settings.gradle
include 'common', 'api', 'web'
def subs(project) {
def children = project.children
children + children.collect { subs(it) }
}
subs(rootProject).flatten().each {
it.buildFileName = "${it.name}.gradle"
}
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Settings object - Including multiprojects

27. Multi Project
build.gradle
subprojects {
apply plugin: 'java'
repositories {
mavenRepo urls: 'http://here'
}
dependencies {
compile 'com.google.guava:guava:10.0'
}
}
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28. Multi Project
build.gradle
subprojects {
apply plugin: 'java'
repositories {
mavenRepo urls: 'http://here'
allprojects {
... }
} dependencies {
compile 'com.google.guava:guava:10.0'
}
}
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29. Multi Project
build.gradle
subprojects {
apply plugin: 'java'
repositories {
mavenRepo urls: 'http://here'
project(‘:common’) {
allprojects {
... }
} dependencies {
compile 'com.google.guava:guava:10.0'
}
}
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30. Multi Project
common/common.gradle
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Empty -> Remove

31. Multi Project
common/common.gradle
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Empty -> Remove

32. Multi Project
api/api.gradle
dependencies {
compile project(‘:common’)
}
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33. Multi Project
web/web.gradle
apply plugin: ‘war’
dependencies {
compile project(‘:api’)
}
war {
webAppDir file(‘src/main/webapp’)
}
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34. Multi Project
myproject
api
common
web
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Built alphabetically
Unless dependencies
Cross module dependencies
•Single cmd to draw out result

35. Multi Project
myproject
api
common
web
20
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Built alphabetically
Unless dependencies
Cross module dependencies
•Single cmd to draw out result

36. Multi Project
myproject
common
api
web
20
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Built alphabetically
Unless dependencies
Cross module dependencies
•Single cmd to draw out result

37. Plugin Support
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Maven plugin (uploads artifacts)
Eclipse/Idea plugin
•Never get the maven integration, nothing can be said before all config is loaded
Java / Groovy / Scala
War / Ear / Antlr / Announce / Application / Jetty
Sonar / Project Report / Code Quality
More on github

38. Writing Own Plugins
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1.Hack it together
2.Copy it
3.Create a plugin

39. IDE Support
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Plugins for Idea and Eclipse
Idea functions very well
Not for gradle code: Gradle support in Idea 11
Netbeans being worked on (by Oracle)

40. IDE Support
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Plugins for Idea and Eclipse
Idea functions very well
Not for gradle code: Gradle support in Idea 11
Netbeans being worked on (by Oracle)

41. IDE Support
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Plugins for Idea and Eclipse
Idea functions very well
Not for gradle code: Gradle support in Idea 11
Netbeans being worked on (by Oracle)

42. IDE Support
?
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Plugins for Idea and Eclipse
Idea functions very well
Not for gradle code: Gradle support in Idea 11
Netbeans being worked on (by Oracle)

43. Performance
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Generally OK
Loads all configuration
•Daemon may fix this
Calculates MD5 sums for inputs/outputs

44. Coming Attractions
NEW
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Release 0.1 @ April 2008
A little immature, version 1.0m3 (1.0m4 withdrawn)
1.0 milestone 5
•Daemon (4)
•EAR, Signing (4)
•Experimental C++
•Multi process safe caches

45. Conclusion
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Strangeness:
•Hard to test plugins
•Low on documentation (search mailing-list)
•Changes can be made to early or to late for the process
•Silent when it’s unable to find a project artifact (due to missing dependencies)
Perfect for reviving ant-projects
Flexible flexible flexible

46. :compileJava UP-TO-DATE
:processResources UP-TO-DATE
END
:classes UP-TO-DATE
:jar UP-TO-DATE
:assemble UP-TO-DATE
:compileTestJava UP-TO-DATE
:processTestResources UP-TO-DATE
:testClasses UP-TO-DATE
:test UP-TO-DATE
:check UP-TO-DATE
:build UP-TO-DATE
BUILD SUCCESSFUL
Total time: 3233.278 secs
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