Custom task type not found when importing Gradle plugin - gradle

Question

I am facing the following conundrum for which I spent a great deal of time trying to resolve with no success so far. I have a custom Gradle plugin whose job is to start a process and run it in the background.
My code plugin code is the following:
public class TaskSpawnerPlugin implements Plugin<Project> {
void apply(Project project) {
project.task('spawnTask', type: TaskSpawner)
}
}
And this is the task in question:
public class TaskSpawner extends DefaultTask {
#Input
String command
#Input
String ready
#Input
String workDir = '.'
TaskSpawner() {
description = 'Given a Unix like cmd, this will start it and let it run on the background'
}
#TaskAction
public void spawn() {
getLogger().quiet "Attempting to run provided command $command"
if (!(command && ready)) {
throw new GradleException("Please make sure that both the command and ready check are provided!")
}
waitFor(createProcess(workDir, command))
}
private def waitFor(Process process) {
new BufferedReader(new InputStreamReader(process.getInputStream())).withCloseable {
reader ->
def line
while ((line = reader.readLine()) != null) {
getLogger().quiet line
if (line.contains(ready)) {
getLogger().quiet "$command is ready"
break
}
}
}
}
private def static createProcess(String directory, String command) {
new ProcessBuilder(command.split(' '))
.redirectErrorStream(true)
.directory(Paths.get(directory).toFile())
.redirectError(ProcessBuilder.Redirect.INHERIT)
.redirectInput(ProcessBuilder.Redirect.INHERIT)
.redirectOutput(ProcessBuilder.Redirect.INHERIT)
.start()
}
}
The code resides under a package structure that has following package name
fts.gradle
My build script looks like this:
plugins {
id 'java-gradle-plugin'
id 'groovy'
id 'maven-publish'
}
group = 'fts.gradle'
version = '0.3'
repositories {
jcenter()
}
dependencies {
compile gradleApi()
compile localGroovy()
}
gradlePlugin {
plugins {
greetingsPlugin {
id = 'fts.gradle.taskspawn'
implementationClass = 'fts.gradle.TaskSpawnerPlugin'
}
}
}
I build my plugin normally and deploy it on a locally hosted artifactory. My problem revolves around how to import it and use it in a project.
For the time being I do the following:
buildscript {
repositories {
maven { url "<maven_url>" }
}
dependencies {
classpath group: 'fts.gradle', name: 'task-spawner', version: '0.3'
}
}
plugins {
id 'java'
id 'application'
id 'eclipse'
}
apply plugin: 'fts.gradle'
And then I attempt to apply it using the following:
But when attempting to refresh the project this action fails:
* What went wrong:
A problem occurred evaluating project ':integration-tests'.
> Could not get unknown property 'TaskSpawner' for project ':integration-tests' of type org.gradle.api.Project.
I have read the documentation and I have tried all the various ways of creating and importing a plugin as a standalone jar but so far I've unsuccessful.
Can anyone please shed some light here? This has been driving nuts for the past days.
Note, for reference the Gradle version I use it 5.6.2