Launch grails command from grails application - grails

Question

I am trying to run a grails command like "grails help" from a Grails application but all the tries I have done end up with "Error: Could not find or load main class org.codehaus.groovy.grails.cli.support.GrailsStarter".
Basically, I have tried
def p1 = "grails help".execute()
p1.waitFor()
println "return code: ${ p1.exitValue()}"
println "stderr: ${p1.err.text}"
println "stdout: ${p1.in.text}"
Also:
Runtime runtime = Runtime.getRuntime()
Process process = runtime.exec("grails help")
process.waitFor()
println "return code: ${ process.exitValue()}"
println "stderr: ${process.err.text}"
println "stdout: ${process.in.text}"
And finally:
def sout = new StringBuffer()
def serr = new StringBuffer()
final processBuilder = new ProcessBuilder()
processBuilder.directory(new File("/myFolder"))
processBuilder.command(["grails","help"])
println processBuilder.directory()
Process proc = processBuilder.start()
proc.consumeProcessOutput(sout, serr)
def status = proc.waitFor()
println 'sout: ' + sout
println 'serr: ' + serr
Of course, the "grails help" command is not the one I want to execute but fixing this one it will fix the one I need to run.
Any other ideas?

Answer 1

If I create a new app with grails 2.3.5 (grails create-app script-test), then declare a controller (grails create-controller test.Run) and change it so it looks like:
package test
class RunController {
def index() {
def t = [ 'grails', 'help' ].execute().text
render "<pre>$t</pre>"
}
}
Then run it with grails run-app, and go to localhost:8080/script-test/run, I get the grails help screen rendered as text to the web-page.
The problem you are going to have is that this won't work in production as you are probably going to deploy a war file, so grails won't be aware of where you are, or what you are doing (if indeed grails is installed on the server)
I think you need to re-think your strategy, whatever it is you are trying to do :-(