有没有一种简单的方法来获取对 url 的请求的响应时间(除了单独跟踪代码中的时间)?
import dispatch._, Defaults._
import scala.util.{Failure, Success}
val svc = dispatch.url(url)
val response: Future[com.ning.http.client.Response] = Http(svc > (x => x))
response onComplete {
case Success(content) => {
println(s"SUCCESS: ${content.getStatusCode()} for $url")
//how long did this take??
}
case Failure(t) => {
println(s"ERROR: timeout/failure for $url")
}
}
这是一种计算经过时间的不同方法,可能需要更多自定义(例如处理故障,NonFatal
最有可能),但我认为这更习惯一些。不过,它仅适用于Future
。
的结果创建一个类(也可以用元组替换),并为随时间变化的失败创建一个类。
import scala.concurrent.Future
import scala.concurrent.ExecutionContext.Implicits.global
case class ResultWithTime[ResultType](val result: ResultType, val time: Long)
class FailureWithTime(failure: Throwable, val time: Long) extends Throwable(failure)
然后创建一个方法,将未来包装为执行并在失败时处理这种情况(如果您不喜欢Future
的map
和recoverWith
方法(因为它们需要隐式ExecutionContext
),可能会使用 Promise
)。
object TimerFuture {
def apply[ResultType](fut: =>Future[ResultType]): Future[ResultWithTime[ResultType]] = {
val startTime = System.currentTimeMillis
fut.map(r => ResultWithTime(r, System.currentTimeMillis - startTime))
.recoverWith{case t:Throwable =>
Future.failed(new FailureWithTime(t, System.currentTimeMillis - startTime))
}
}
}
下面是如何使用它的示例:
import scala.concurrent.Future
import scala.concurrent.ExecutionContext.Implicits.global
import scala.io.StdIn
object Y extends App {
TimerFuture(Future{Thread.sleep(200); "Hello"})
.onSuccess({case ResultWithTime(r, t) => println(s"Took $t ms to get: $r")})
TimerFuture(Future{Thread.sleep(100); throw new NullPointerException()})
.onFailure({case f: FailureWithTime => println(s"Took ${f.time} ms to get: ${f.getCause}")})
StdIn.readLine()
}
你可以用这样的东西包装你的代码(未经测试):
class Timer[ResultType](computation: =>Future[ResultType]) {
private val startTime = System.currentTimeMillis
val result: Future[ResultType] = computation
private var endTime: Option[Long] = None
result.onComplete{case _ => endTime = Some(System.currentTimeMillis)}
def responseTime: Option[Long] = endTime.map(_ - startTime)
//probably also provide onComplete and other Future methods wrapping result.
}
object Timer{
def apply[ResultType](computation: =>Future[ResultType]) = {
new Timer(computation)
}
}
您可以使用配套对象中的工厂方法创建更具体的计时器,以帮助处理要测量的计算。
用法:
val timedComputation = Timer{Http(svc > (x => x))}
timedComputation.result.onComplete{case _ => ???}
//In a completed event:
val responseTimeInMillis: Long = timedComputation.responseTime.get