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Scala Akka HTTP core instrumentation

With the introduction of Java agent release 7.8.0, changes were made to remove the default instrumentation of the bindAndHandle method, to eliminate scenarios that could result in erroenously duplicated transactions being reported. In some situations, it may be necessary for you to make explicit method calls to compensate for this change.

Background: HttpExt instrumentation

Instrumentation for Akka HTTP Core is carried out in the akka.http.scaladsl.HttpExt class that serves as the main entry point for a server. Two convenience methods from HttpExt that can be used to start an HTTP server have been instrumented:

  • bindAndHandleAsync: A convenience method which starts a new HTTP server at the given endpoint and uses a handler that is a function receiving an HttpRequest and returning a Future[HttpResponse]
  • bindAndHandleSync: A convenience method which starts a new HTTP server at the given endpoint and uses a handler that is a function receiving an HttpRequest and returning a HttpResponse

To eliminate the erroneous duplication of transactions from being reported, intrumentation is no longer being applied to the bindAndHandle method, which starts a new HTTP server using a akka.stream.scaladsl.Flow instance.

The duplication of transactions is due to a clash in the Akka Http Routing DSL instrumentation.

Solution - explicitly call bindAndHandleAsync

If you wish to start an HTTP server from an akka.stream.scaladsl.Flow, you must explicitly invoke the bindAndHandleAsync method. For example:

...
val flow: Flow[HttpRequest, HttpResponse, NotUsed] = ???
val asyncHandler: HttpRequest => Future[HttpResponse] = request => Source.single(request).via(flow).runWith(Sink.head)
Http().bindAndHandleAsync(asyncHandler, host, port)
...

Important

A similar workaround, calling bindAndHandle when starting an HTTP server from a akka.http.scaladsl.Route using the Akka HTTP Routing DSL, is not necessary. Agent instrumentation will work normally when being called from other convenience methods.

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