Akka-HTTP creating a directive to create a unique request id?

[kraythe]

Greetings, 

I am currently using the low level API but lookign again at the DSL. I have been trying to figure out if there is a way to create a directive that creates a unique request UUID and allows other directives to access that UUID in every sub directive. Basically I want something like 

withRequestId {

  requestId = UUID.randomUUID()

  pathSingleSlash {

    comlete(requestId.toString)

  }

}

I want this to be universal so the outer directive defines the id and the rest of the routes dont have to bother. I dont like copy past code. Any idea if and how this could be done? 

[Arnout Engelen]

Hello,

You could create a Directive1[UUID] which can then be used like this:

withRequestId { requestId =>

  pathSingleSlash {

    comlete(requestId.toString)

  }

}

Is that what you're looking for? See http://doc.akka.io/docs/akka-http/10.0.9/scala/http/routing-dsl/directives/custom-directives.html#directives-from-scratch for more details.

Kind regards,

Arnout

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Arnout Engelen

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[kraythe]

Thanks but I don't understand how I can make the request id available inside the rest of the route. 

On Thursday, August 24, 2017 at 4:08:01 AM UTC-5, Arnout Engelen wrote:

Hello,

You could create a Directive1[UUID] which can then be used like this:

withRequestId { requestId =>

  pathSingleSlash {

    comlete(requestId.toString)

  }

}

Is that what you're looking for? See http://doc.akka.io/docs/akka-http/10.0.9/scala/http/routing-dsl/directives/custom-directives.html#directives-from-scratch for more details.

Kind regards,

Arnout

On Thu, Aug 24, 2017 at 1:55 AM, kraythe <kra...@gmail.com> wrote:

Greetings, 

I am currently using the low level API but lookign again at the DSL. I have been trying to figure out if there is a way to create a directive that creates a unique request UUID and allows other directives to access that UUID in every sub directive. Basically I want something like 

withRequestId {

  requestId = UUID.randomUUID()

  pathSingleSlash {

    comlete(requestId.toString)

  }

}

I want this to be universal so the outer directive defines the id and the rest of the routes dont have to bother. I dont like copy past code. Any idea if and how this could be done? 

--
>>>>>>>>>> Read the docs: http://akka.io/docs/
>>>>>>>>>> Check the FAQ: http://doc.akka.io/docs/akka/current/additional/faq.html
>>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user
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[kraythe]

I should be more specific. Ok if I do what you say then the request id will be available in the route via being closed over .. I guess I just don't grok how the DSL works. So I will just have to mess with it. My lack of understanding has to do with the type of the argument to withRequestId ... its a function that returns a route? I will mess with this some more. 

On Thursday, August 24, 2017 at 4:08:01 AM UTC-5, Arnout Engelen wrote:

Hello,

You could create a Directive1[UUID] which can then be used like this:

withRequestId { requestId =>

  pathSingleSlash {

    comlete(requestId.toString)

  }

}

Is that what you're looking for? See http://doc.akka.io/docs/akka-http/10.0.9/scala/http/routing-dsl/directives/custom-directives.html#directives-from-scratch for more details.

Kind regards,

Arnout

On Thu, Aug 24, 2017 at 1:55 AM, kraythe <kra...@gmail.com> wrote:

Greetings, 

I am currently using the low level API but lookign again at the DSL. I have been trying to figure out if there is a way to create a directive that creates a unique request UUID and allows other directives to access that UUID in every sub directive. Basically I want something like 

withRequestId {

  requestId = UUID.randomUUID()

  pathSingleSlash {

    comlete(requestId.toString)

  }

}

I want this to be universal so the outer directive defines the id and the rest of the routes dont have to bother. I dont like copy past code. Any idea if and how this could be done? 

--
>>>>>>>>>> Read the docs: http://akka.io/docs/
>>>>>>>>>> Check the FAQ: http://doc.akka.io/docs/akka/current/additional/faq.html
>>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user
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[B Wills]

Hi,

We do something similar - instead of writing a custom directive, we generate a unique request ID and then put this in the response as a header using the respondWithHeader directive.  For example:

respondWithHeader(RawHeader("Request-ID", requestId)) {
  pathPrefix(serviceConfig.getString("self.version")) {
    extractClientIP { ip =>

This is in an outer level of our routing structure.  To be a bit more clear:

def routes = {
    extractUri { URI =>
      val uri = URI.toString()
      val requestId = Utils.generateRequestId()

      respondWithHeader(RawHeader("Request-ID", requestId)) {
        pathPrefix(serviceConfig.getString("self.version")) {
          extractClientIP { ip =>
            optionalHeaderValueByName("User-Agent") { agent =>
              path("path") {
                pathEnd {
                  get {

[Jeremy Townson]

Because the uuid does not depend on the request in any way, you can map a directive called 'pass' (pass is a a sort of identity directive that does nothing). e.g.

  "directive" should "generate a uuid" in {

    import akka.http.scaladsl.server.Directives.pass

    val uuid = UUID.randomUUID().toString

    val withRequestId: Directive1[String] = pass.tmap(_ => uuid)

    val route = withRequestId { (requestId: String) =>

      complete(requestId)

    }

    Get("http://example.com") ~> route ~> check {

      responseAs[String] shouldBe uuid

    }

  }