I have a build.gradle file that's fairly long, and I'd like to break some of the logic up into smaller files to make the whole thing more maintainable. After moving some tasks into a new file, I found that none of the variables I had set in the parent script were available in the child script. Below is a pair of source files I reproduced this behavior with:
build.gradle:
apply from: 'repro.gradle'
def foo = "This is a variable"
tasks.register('printFromMainScript') {
println(foo)
}
repro.gradle:
tasks.register('printFromChildScript') {
println(foo)
}
In the above example, printFromMainScript works fine, but printFromChildScript fails. Is there a way to access foo from repro.gradle?
def foo creates a variable that exists only in the scope of build.gradle. Gradle documentation explains this more in detail.
There is ext block in Gradle which is meant for extra properties.
This should work in your case:
build.gradle:
apply from: 'repro.gradle'
ext {
foo = "This is a variable"
}
repro.gradle:
task printFromChildScript {
doLast {
println(project.foo)
}
}
Note: doLast block ensures that the println function is called only when the project is fully configured and printFromChildScript is actually executed. If you put println directly in task body then it will be executed during Gradle project configuration phase.
Related
I'm trying to configure a Zip task based on one of the property inside sub-projects, but the property is not yet accessible at the time of configuring the task. For instance, I want to exclude all my projects that has toexclude = true from my zip file. So, the build.gradle of the sub-projects that I want to exclude starts with this:
ext.toexclude = true;
...
And my main build.gradle has this task:
task zipContent (type: Zip){
def excludedProjects = allprojects.findAll{Project p -> p.toexclude == true}.collect{it.name}
println excludedProjects
destinationDir = "/some/path"
baseName = "myFile.zip"
exclude excludedProjects
from "/some/other/path"
}
The problem is that excludedProjects is always empty. Indeed, when I am executing the task, I can see []. I believe this is due to the fact that the property that I set in the subproject's build.gradle is not available at the moment the task is configured. As a proof, if I replace the first line of the task by this:
def excludedProjects = allprojects.collect{it.name}
The task prints out all of my project's name, and the zip contains nothing (which means the problem is in the p.toexclude == true).
Also, if I try this:
task zipContent (type: Zip){
def excludedProjects = []
doFirst{
excludedProjects = allprojects.findAll{Project p -> p.toexclude == true}.collect{it.name}
println "IN DOFIRST"
println excludedProjects
}
println "IN TASK CONFIG"
println excludedProjects
destinationDir = "/some/path"
baseName = "myFile.zip"
exclude excludedProjects
from "/some/other/path"
}
The task prints out IN TASK CONFIG followed by an empty array, then IN DOFIRST with the array containing only the subprojects that I set ext.toexclude == true.
So, is there a way to get the properties of the sub-projects at configuration time?
Well, the crucial question is: At which point of the build is all necessary information available?
Since we want to know each project in the build, where the extra property toexclude is set to true and it is possible (and by design) that the property is set via the build script, we need each build script to be evaluated.
Now, we have two options:
By default, subprojects are evaluated after the parent (root) project. To ensure the evaluation of each project, we need to wait for the point of the build, where all projects are evaluated. Gradle provides a listener for that point:
gradle.addListener(new BuildAdapter() {
#Override
void projectsEvaluated(Gradle gradle) {
tasks.getByPath('zipContent').with {
exclude allprojects.findAll { it.toexclude }.collect{ it.name }
}
}
})
Gradle provides the method evaluationDependsOnChildren(), to turn the evaluation order around. It may be possible to use your original approach by calling this method before querying the excluded projects. Since this method only applies on child projects, you may try to call evaluationDependsOn(String) for each project in the build to also apply for 'sibling' projects. Since this solution breaks Gradle default behavior, it may have undesired side effects.
Just define excludedProjects outside the task
def excludedProjects = allprojects.findAll{Project p -> p.toexclude == true}.collect{it.name}
task zipContent (type: Zip){
destinationDir = file("/some/path")
baseName = "myFile.zip"
exclude excludedProjects
from "/some/other/path"
}
You can call evaluationDependsOnChildren() in the root project so that child projects are evaluated before the root
Eg
evaluationDependsOnChildren()
task zipContent (type: Zip) { ... }
Another option is to use an afterEvaluate { ... } closure to delay evaluation
Eg:
afterEvaluate {
task zipContent (type: Zip) { ... }
}
First, there are some common scripts deployed in private maven repo:
http://domain/repo/com/d/build/script/java-project/1.0/java-project-1.0.gradle
http://domain/repo/com/d/build/script/maven/1.0/maven-1.0.gradle
In the target project, build.gradle
subprojects {
apply from: 'http://domain/repo/com/d/build/script/java-project/1.0/java-project-1.0.gradle'
apply from: 'http://domain/repo/com/d/build/script/maven/1.0/maven-1.0.gradle'
}
it's OK!
but,
ext.applyScript = { script, version ->
apply from: "http://domain/repo/com/d/build/script/${script}/${version}/${script}-${version}.gradle"
}
subprojects {
applyScript('java-project', '1.0')
applyScript('maven', '1.0')
}
it will fail, with message:
"Error:Cannot add task ':javadocJar' as a task with that name already exists."
task ':javadocJar' is defined in script 'java-project-1.0.gradle'
and we have several sub projects.
why ?
BTW: anyone can give me a lead of source location of "apply from:"?
It's hard to location it by myself.
The problem is that in the latte case you are applying the scripts multiple times to the same root project.
How is that possible? It is quite interesting and a little bit tricky:
you are defining applyScript as a Closure on the extension container ext of the current Gradle project,
generally the apply from: ... is handled as a method call apply(Map) on the org.gradle.api.plugins.PluginAware interface which is one of the super interfaces of the org.gradle.api.Project interface
this means every time you write apply ... you are calling the apply method on the current Gradle project (the one where the apply ... is specified)
as you defined the apply ... as part of the closure, the standard delegation applies
it is semantically the same as this.apply ...
this by default points to the enclosing class/object which is the root project (here it cannot be anything else)
So even if it looks like you are applying the 2 scripts to all the subprojects, you are actually applying the 2 scripts N times to the root project (N is the number of subprojects).
What you need to do is to change the delegate to the correct Project instance.:
you can do it very easily by adding one additional argument to the closure and explicitly calling the apply method on that argument:
ext.applyScript = { project, script, version ->
project.apply from: "..."
}
subprojects {
applyScript(it, 'java-project', '1.0')
applyScript(it, 'maven', '1.0')
}
or you can set the delegate explicitly:
ext.applyScript = { script, version ->
apply from: "..."
}
subprojects {
applyScript.resolveStrategy = Closure.DELEGATE_FIRST
applyScript.delegate = it
applyScript('java-project', '1.0')
applyScript('maven', '1.0')
}
What is the difference between these two tasks. Only task with << in its definition is shown in the output of ./gradlew tasks.
task greet(type: GreetingToFileTask) {
destination = { project.greetingFile }
}
task sayGreeting(dependsOn: greet) << {
println file(greetingFile).text
}
The lines above are from gradle documentation Here
The << is a shortcut to the toLast configuration item of a task definition. I.e. the following two declarations are equivalent:
task hello << {
println 'Hello world!'
}
and:
task hello {
doLast {
println 'Hello world!'
}
}
(example taken from Gradle documentation here).
Now, in the first code snippet you just define a task and configuring its destination property. However, the task will only be executed if needed.
In the second code snippet, however, you are actually defining an action that will always be executed during the configuration phase, regardless of the tasks targeted for execution (cite from here):
A task has both configuration and actions. When using the <<, you are
simply using a shortcut to define an action. Code defined in the
configuration section of your task will get executed during the
configuration phase of the build regardless of what task was targeted.
I have got a little problem with variables / ext properties in gradle.
In my root project i have this:
task foo {
println project.fooContent
}
in my child project fooContent is defined like this:
ext { fooContent='somethingProjectSpecific' }
When executing :childproject:foo it says variable is not set.
Do you know how to circumvent that problem?
This variable is not set since you try to print it at configuration phase. Try with an action (<<) it will be printed on execution phase:
task foo << {
println project.fooContent
}
I want to make my gradle build inteligent when building my model.
To acquire this I was planning to read schema files, acquire what is included and then build firstly included models (if they are not present).
I'm pretty new to Groovy and Gradle, so please that into account.
What I have:
build.gradle file on root directory, including n subdirectories (subprojects added to settings.gradle). I have only one gradle build file, because I defined tasks like:
subprojects {
task init
task includeDependencies(type: checkDependencies)
task build
task dist
(...)
}
I will return to checkDependencies shortly.
Schema files located externally, which I can see.
Each of them have from 0 to 3 lines of code, that say about dependencies and looks like that:
#include "ModelDir/ModelName.idl"
In my build.gradle I created task that should open, and read those dependencies, preferably return them:
class parsingIDL extends DefaultTask{
String idlFileName="*def file name*"
def regex = ~/#include .*\/(\w*).idl/
#Task Action
def checkDependencies(){
File idlFile= new File(idlFileName)
if(!idlFile.exists()){
logger.error("File not found)
} else {
idlFile.eachLine{ line ->
def dep = []
def matcher = regex.matcher(line)
(...)*
}
}
}
}
What should I have in (...)* to find all dependencies and how should I define, that for example
subprojectA::build.dependsOn([subprojectB::dist, subprojectC::dist])?
All I could find on internet created dep, that outputted given:
[]
[]
[modelName]
[]
[]
(...)