Applying Gradle plugin from local file - gradle

Question

I have the following gradle plugin that does the job of starting up a java process. The code for this lives under a file named startAppServerPlugin.gradle under the project's buildSrc directory.
The code of the plugin looks like this:
repositories.jcenter()
dependencies {
localGroovy()
gradleApi()
}
}
public class StartAppServer implements Plugin<Project> {
#Override
void apply(Project project) {
project.task('startServer', type: StartServerTask)
}
}
public class StartServerTask extends DefaultTask {
String command
String ready
String directory = '.'
StartServerTask(){
description = "Spawn a new server process in the background."
}
#TaskAction
void spawn(){
if(!(command && ready)) {
throw new GradleException("Ensure that mandatory fields command and ready are set.")
}
Process process = buildProcess(directory, command)
waitFor(process)
}
private waitFor(Process process) {
def line
def reader = new BufferedReader(new InputStreamReader(process.getInputStream()))
while ((line = reader.readLine()) != null) {
logger.quiet line
if (line.contains(ready)) {
logger.quiet "$command is ready."
break
}
}
}
private static Process buildProcess(String directory, String command) {
def builder = new ProcessBuilder(command.split(' '))
builder.redirectErrorStream(true)
builder.directory(new File(directory))
def process = builder.start()
process
}
}
I'm trying to figure out a way of having this imported into my main build.gradle file due everything I tried so far has been unsuccessful.
So far I have tried this:
apply from: 'startAppServerPlugin.gradle'
apply plugin: 'fts.gradle.plugins'
But it has been failing. I've tried searching online for examples of doing what I need to do but so far I've been unsuccessful. Can anyone please provide a hint as to how I'm supposed to do so?

Answer 1

The buildSrc folder is treated as an included build, where the code is compiled and put on the classpath of the surrounding project. The actual build.gradle file in buildSrc is only used for compiling that project, and the things you put in it will not be available elsewhere.
You are supposed to create your classes as a normal Java/Groovy/Kotlin project under buildSrc. I don't know if you can use the default package, but it is generally best practice to have a package name anyway.
For example, your StartAppServer plugin should be in buildSrc/src/main/groovy/my/package/StartAppServer.groovy. Then you can apply it in your build scripts with apply plugin: my.package.StartAppServer.
There are a lot of good examples in the user guide.

Answer 2

You are on the right path. The first order of business is to import the external gradle build using:
apply from: 'startAppServerPlugin.gradle'
Then you can apply the plugin with:
apply plugin: StartAppServer
See Script Plugins and Applying Binary Plugins