Gradle task not executed if added as a dependency

Question

I have two gradle tasks in my build.gradle file, one to archive a folder and another to push it to a remote server.

task tarTask(type: Exec) {
    commandLine 'tar', '-czf', 'javadocs.tgz', 'javadocs/'
}

If I execute tarTask alone with gradle tarTask and with the publish task commented out, the build succeeds. I am using this task as a dependency in the publish task.

task publish(dependsOn: tarTask) {
    ssh.run {
        settings {
            knownHosts = allowAnyHosts
            fileTransfer = 'scp'
        }

        session(remotes.webServer) {
            from: 'javadocs.tgz', into: 'publishingHouse/'
        }
    }
}

But when i execute gradle publish it fails saying that it is not able to find the tgz file which should have been created if the previous task is executed.

java.io.FileNotFoundException: javadocs.tgz

Being new to gradle i am not really sure what I am missing here. Any ideas on what I can do?

Answer 1

I suppose the reason is within the phase when tasks are executed. tarTask is configured at the configuration phase and will be executed at the execution phase.

And at the same time publish task doesn't have any behavior to execute at the execution phase, but has ssh.run to be executed during configuration.

This mean, that when you run gradle publish your logic to copy tar-archive is executed at the configuration phase, while tar-archive is not yet exists (it will be created later at the execution phase).

To make a copy execution at the execution phase you can simply add << to the publish task declaration as follows:

task publish(dependsOn: tarTask) << {
    ssh.run {
        settings {
            knownHosts = allowAnyHosts
            fileTransfer = 'scp'
        }

        session(remotes.webServer) {
            from: 'javadocs.tgz', into: 'publishingHouse/'
        }
    }
}

Note, that << is the same as doLast and the closure will be excuted at the execution phase. You can read about Gradle build lifecycle here