Using groovy classes within Gradle build

Question

I'm trying to run a Groovy class from within my build.gradle file. I'm following the direction in the use guide however I get an error.

The build file is:

apply plugin: 'java'
apply plugin: 'groovy'

  main {
    java {
      srcDirs = ["$projectDir/src/java"]
    }
    groovy {
      srcDirs = ["$projectDir/src/groovy"]
    }
  }

    dependencies {
        compile 'org.codehaus.groovy:groovy-all:2.2.0', files(....)
    }

    task fooTask << {
        groovyClass groovyClass = new groovyClass()
        groovyClass.foo()
    }

The groovy class is very simple:

    public class groovyClass {

            public void foo() {
                    println 'foo'
            }
    }

However when I try to run gradlew compile fooTask I get the following error:

unable to resolve class groovyClass

Any idea why?

Thanks

Solution

You need to add the class to buildSrc if you want to reference it from the build (and not in a simple Exec task). Given this directory structure:

|-buildSrc
|    |- src
|        |- main
|            |- groovy
|                |- GroovyClass.groovy
|- build.gradle

Where GroovyClass.groovy is:

class GroovyClass {
    void foo() {
        println 'foo'
    }
}

And build.gradle is:

apply plugin: 'groovy'

dependencies {
    compile 'org.codehaus.groovy:groovy-all:2.2.1'
}

task fooTask << {
    GroovyClass g = new GroovyClass()
    g.foo()
}

Then, running gradle fooTask gives the output:

$ gradle fooTask
:buildSrc:compileJava UP-TO-DATE
:buildSrc:compileGroovy UP-TO-DATE
:buildSrc:processResources UP-TO-DATE
:buildSrc:classes UP-TO-DATE
:buildSrc:jar UP-TO-DATE
:buildSrc:assemble UP-TO-DATE
:buildSrc:compileTestJava UP-TO-DATE
:buildSrc:compileTestGroovy UP-TO-DATE
:buildSrc:processTestResources UP-TO-DATE
:buildSrc:testClasses UP-TO-DATE
:buildSrc:test UP-TO-DATE
:buildSrc:check UP-TO-DATE
:buildSrc:build UP-TO-DATE
:fooTask
foo

BUILD SUCCESSFUL

Total time: 4.604 secs

Comments

[jonatzin]

Do you know if there is a way to change where gradle looks for the classes, so instead of buildSrc/src/main/groovy it will look for it at src/main/groovy?

[tim_yates]

Not that I know of. To run the build it will have first had to run the build, so you get a chicken and egg situation. Not sure if a symbolic link in buildSrc to the groovy file in SRC will work if the file is required in both and you don't want to maintain two files?

[Louis]

gradle will fetch your groovy sources in srcDirs from your build.gradle. Put whatever path you would like to be a gradle source directory and you're good to go.