Execute gradle task on sub projects - gradle

Question

I have a MultiModule gradle project that I am trying to configure.
Root
projA
projB
other
projC
projD
projE
...
What I want to be able to do is have a task in the root build.gradle which will execute the buildJar task in each of the projects in the other directory.
I know I can do
configure(subprojects.findAll {it.name != 'tropicalFish'}) {
task hello << { task -> println "$task.project.name"}
}
But this will also get projA and projB, I want to only run the task on c,d,e...
Please let me know the best way to achieve this.

Answer 1

Not entirely sure which of these you're after, but they should cover your bases.
1. Calling the tasks directly
You should just be able to call
gradle :other/projC:hello :other/projD:hello
I tested this with:
# Root/build.gradle
allprojects {
task hello << { task -> println "$task.project.name" }
}
and
# Root/settings.gradle
include 'projA'
include 'projB'
include 'other/projC'
include 'other/projD'
2. Only creating tasks in the sub projects
Or is it that you only want the task created on the other/* projects?
If the latter, then the following works:
# Root/build.gradle
allprojects {
if (project.name.startsWith("other/")) {
task hello << { task -> println "$task.project.name" }
}
}
and it can then be called with:
$ gradle hello
:other/projC:hello
other/projC
:other/projD:hello
other/projD
3. Creating a task that runs tasks in the subprojects only
This version matches my reading of your question meaning there's already a task on the subprojects (buildJar), and creating a task in root that will only call the subprojects other/*:buildJar
allprojects {
task buildJar << { task -> println "$task.project.name" }
if (project.name.startsWith("other/")) {
task runBuildJar(dependsOn: buildJar) {}
}
}
This creates a task "buildJar" on every project, and "runBuildJar" on the other/* projects only, so you can call:
$ gradle runBuildJar
:other/projC:buildJar
other/projC
:other/projC:runBuildJar
:other/projD:buildJar
other/projD
:other/projD:runBuildJar
Your question can be read many ways, hope this covers them all :)

Answer 2

All of the ways mentioned by Mark can be used but all of them have some cons. So I am adding one more option:
4. Switching the current project
gradle -p other hello
This switches the "current project" and then runs all tasks named hello under the current project.

Answer 3

Example 5. Defining common behavior of all projects and subprojects,
allprojects {
task hello {
doLast { task ->
println "I'm $task.project.name"
}
}
}
subprojects {
hello {
doLast {
println "- I depend on water"
}
}
}
From the Gradle documentation,
https://docs.gradle.org/current/userguide/multi_project_builds.html