Track execution time per task in gradle script?

Question

What is the most elegant way to track the execution times on how long a task took in a gradle build script? In an optimal case log the time directly same or next line to the tas

Answer 1

Just to elaborate on Peter Niederwieser's answer: We wanted to do the same thing, as well as a report timings at the end of the build, so slow steps are obvious (and appropriate parties feel a small but healthy bit of shame when they slow down the build!).

BUILD SUCCESSFUL

Total time: 1 mins 37.973 secs
Task timings:
    579ms  :myproject-foo:clean
  15184ms  :myproject-bar:clean
   2839ms  :myproject-bar:compileJava
  10157ms  :myproject-bar:jar
    456ms  :myproject-foo:compileJava
    391ms  :myproject-foo:libs
    101ms  :myproject-foo:jar
    316ms  :myproject-bar:compileTestJava
    364ms  :myproject-foo:compileTestJava
  53353ms  :myproject-foo:test
   2146ms  :myproject-bar:test
   8348ms  :www/node:npmInstall
    687ms  :www/node:npmTest

Something like the code below can be dropped into your top level build.gradle to report timings during execution, or after completion.

// Log timings per task.
class TimingsListener implements TaskExecutionListener, BuildListener {
    private Clock clock
    private timings = []

    @Override
    void beforeExecute(Task task) {
        clock = new org.gradle.util.Clock()
    }

    @Override
    void afterExecute(Task task, TaskState taskState) {
        def ms = clock.timeInMs
        timings.add([ms, task.path])
        task.project.logger.warn "${task.path} took ${ms}ms"
    }

    @Override
    void buildFinished(BuildResult result) {
        println "Task timings:"
        for (timing in timings) {
            if (timing[0] >= 50) {
                printf "%7sms  %s\n", timing
            }
        }
    }

    @Override
    void buildStarted(Gradle gradle) {}

    @Override
    void projectsEvaluated(Gradle gradle) {}

    @Override
    void projectsLoaded(Gradle gradle) {}

    @Override
    void settingsEvaluated(Settings settings) {}
}

gradle.addListener new TimingsListener()