README.md

Watch-A-Doin'?

Simple Kotlin library that can be used to monitor timings of some expensive operations and nested calls they make.

Using this library can help you in identifying the most offending timings and figuring out future solutions towards general betterness.

Getting started

This repository is hosted via jitpack since it's by far the easiest delivery method while also being pretty transparent to the developer.

Make sure you have added jitpack to the list of your repositories:

maven("https://jitpack.io")

Then simply add the watch-a-doin dependency

dependencies {
    compile("com.github.eyeem:watch-a-doin:master-SNAPSHOT")
}

Example usage

val loopWatch = Stopwatch("🔁 loop")

fun expensiveOperation(stopwatch: Stopwatch) = stopwatch {
    Thread.sleep(125)
}

fun moreExpensiveOperation(stopwatch: Stopwatch) = stopwatch {
    Thread.sleep(375)
}

loopWatch {
    for (i in 0 until 4) {
        "⏭️ iteration $i".watch {
            expensiveOperation("🕰️".watch)
            moreExpensiveOperation("🕰 x3".watch)
        }
    }
}

println(loopWatch.toStringPretty())

loopWatch.saveAsSvg(File("loopWatch.svg"))
loopWatch.saveAsHtml(File("loopWatch.html")) // interactive svg with pan and zoom

Will print this:

🔁 loop [2018ms @0ms]
 ⏭️ iteration 0 [506ms @0ms]
  🕰️ [127ms @0ms]
  🕰 x3 [379ms @127ms]
 ⏭️ iteration 1 [506ms @506ms]
  🕰️ [127ms @506ms]
  🕰 x3 [379ms @633ms]
 ⏭️ iteration 2 [503ms @1012ms]
  🕰️ [128ms @1012ms]
  🕰 x3 [375ms @1140ms]
 ⏭️ iteration 3 [503ms @1515ms]
  🕰️ [128ms @1515ms]
  🕰 x3 [375ms @1643ms]

and create the following SVG:

Timeouts

Some stopwatches might finish after others, some might never finish. Consider following example using launch.

val baseWatch = Stopwatch("runBlocking")

baseWatch {
    runBlocking {
        "launch".watch {
            launch {
                "insideLaunch".watch {
                    delay(500)
                }
            }
        }
    }
}

Now if we make insideLaunch watch never call end (e.g. due to some error) the top watch will timeout it on its end.

val insideWatch = "insideLaunch".watch
insideWatch.start()
delay(500)
// insideWatch.end()

Timeout timelines are marked red.

You can explicitly timeout any watch with timeout() method or timeout any running child watches with timeoutAllRunningChildren().

NOTE: If end() is called after timeout() it will only update timeout time.

More Resources

• Watcha Doin'? Inspecting Kotlin coroutines with timing graphs. - Medium Article