Command line task

Old Forum Archive
1

I have a gradle task I wrote that runs something on the command line. The process takes ~15 seconds and writes its status to the console. I want to take action based on the status that is written to the console. I see the standardOutputStream property for an Exec task but anytime I println that it seems to print to the console first and then my process finally writes to the console. How do I handle this situation in gradle?

2

I’m not sure what exactly you’re exec’ing (which might have special output behavior that I’m not aware of)…

Could the process be sending things to std error that you’re not intercepting?

3

I am running my jasmine js unit tests via phantom js(headless webkit tool).

Here is my task definition on my local machine

task runJasmine(type: Exec) {
    workingDir '/src/main/webapp/resources/js/tests/'
      //windows
     commandLine 'cmd', '/c', 'phantomjs jasmine_phantom.js SpecRunner.html results.html'
        println 'execResult ' + execResult
    println 'stdOut ' + standardOutput
    println 'stdIn ' + standardInput
}

Here is the output I am seeing where the printlns in the task seem to print to the console before the script that is running phantom does.

execResult null stdOut org.apache.commons.io.output.CloseShieldOutputStream@1ef479c2 stdIn java.io.ByteArrayInputStream@4465bf6e :my-project:runJasmine

------------------------------------------------------- J A S M I N E

T E S T S -------------------------------------------------------

Test URL: SpecRunner.html Tests completed in 2408 ms Test results file: results.html Tests passed.

BUILD SUCCESSFUL

Total time: 19.377 secs

4

By default, forked processes write through to the parent processes stdout. This isn’t what you want. You want to collect the output and then parse it.

task runJasmine(type: Exec) {
    workingDir '/src/main/webapp/resources/js/tests/'
    //windows
     commandLine 'cmd', '/c', 'phantomjs jasmine_phantom.js SpecRunner.html results.html'
   standardOutput = new ByteArrayOutputStream()
     doLast {
     String output = standardOutput.toString()
   }
}
1 Like
5

The execResult is null because the task hasn’t ran yet.

Printing the standardOutput/input they way you do it is not quite right because:

  • you’re printing it at configuration phase

  • printing it only prints the string representation of the default stream (by default, Gradle uses System.out). If you want to get hold of the output, assign brand new ByteArrayOutputStream. Take a look at the example:

task foo(type: Exec) {
  commandLine = //
      //store the output instead of printing to the console
  standardOutput = new ByteArrayOutputStream()
      //extension method foo.output() can be used to obtain the output String
  ext.output = {
    return standardOutput.toString()
  }
  }
  task showFooOutput(dependsOn: foo) {
  doLast {
    println "Foo's output: ${foo.output()}"
  }
}

Hope that helps!

6

@Luke - This version of the task worked @Szczepan - I don’t understand this example 100%. Where is ext referring to? What is it? When I lookup exec task I don’t see ext as property listed (perhaps its inherited?).

7

ext refers to: http://gradle.org/docs/current/dsl/org.gradle.api.plugins.ExtraPropertiesExtension.html

8

Thanks that was really helpful. I never knew it existed

9

Do you guys have any suggestions on how to fail the build if that text indicates failure?

10

You can just throw an exception.