Extract Scala function name and params implicitly - scala

Question

I have the following code:
def disableRules(someId: String) = Action.async { implicit req =>
Metrics.measureTime("disableRules") {
someFutureOpr(someId).map(_ => Ok)
.recover {
case e: Exception => handlerError(s"Failure occurred on disableRules request ${e.getMessage}", "disableRules")
}
}
}
def activeRules(someId: String) = Action.async { implicit req =>
Metrics.measureTime("activeRules") {
someFutureOpr2(someId).map(_ => Ok)
.recover {
case e: Exception => handlerError(s"Failure occurred on activeRules request ${e.getMessage}", "activeRules")
}
}
}
...
As you can see, I have mesureTime and handleError functions that I pass to them the name of the function as String, is there way to make it implicitly, I mean its will take the function Name, if not - there way to extract the function Name and print it, also regarding params.

Answer 1

You can solve this with a macro (and no runtime reflection):
import scala.language.experimental.macros
import scala.reflect.macros.blackbox
class CaptureImpl(val c: blackbox.Context) {
import c.universe._
def describe[T: c.WeakTypeTag](
expr: c.Expr[T]
): c.Expr[String] = c.Expr[String](q"(${expr.tree.toString()})")
}
object CaptureMethod {
def apply[T](expr: T): String = macro CaptureImpl.describe[T]
}
Example:
object Test {
def foo(): String = "hello"
def bar(a: Int): Int = a
def baz(s: String): String = s
def main(args: Array[String]): Unit = {
println(CaptureMethod(foo()))
println(CaptureMethod(bar(1)))
println(CaptureMethod(baz("yes")))
}
}
Yields:
Test.this.foo()
Test.this.bar(1)
Test.this.baz("yes")

Answer 2

Calculate it inside Metrics:
object Metrics {
def currentMethodName() : String = Thread.currentThread.getStackTrace()(3).getMethodName
def measureTime(): Unit = {
println(currentMethodName)
}
}
Then for example:
def a1() = {
Metrics.measureTime()
}
def a2() = {
Metrics.measureTime()
}
will output:
a1
a2
Is this a safe operation?
If we had:
def currentMethodName() : String = Thread.currentThread.getStackTrace.toList.mkString("\n")
we get:
java.lang.Thread.getStackTrace(Thread.java:1559)
HelloWorld1$Metrics$.currentMethodName(HelloWorld1.scala:69)
HelloWorld1$Metrics$.measureTime(HelloWorld1.scala:72)
HelloWorld1$.a1(HelloWorld1.scala:77)
HelloWorld1$.main(HelloWorld1.scala:103)
HelloWorld1.main(HelloWorld1.scala)
So we see that:
In index 0 we get getStackTrace.
In index 1 we have currentMethodName.
In index 2 we have measureTime.
Since measureTime is not the first method of the stack trace, fir sure we have another element in the stack trace. Therefore in your case yes, it is safe.