spray and actor non deterministic tests - scala

Helo,
at the beginning i wold like to apologize for my english :)
akka=2.3.6
spray=1.3.2
scalatest=2.2.1
I encountered strange behavior of teting routes, which asks actors in handleWith directive,
I've route with handleWith directive
pathPrefix("firstPath") {
pathEnd {
get(complete("Hello from this api")) ~
post(handleWith { (data: Data) =>{ println("receiving data")
(dataCalculator ? data).collect {
case Success(_) =>
Right(Created -> "")
case throwable: MyInternalValidatationException =>
Left(BadRequest -> s"""{"${throwable.subject}" : "${throwable.cause}"}""")
}
}})
}
}
and simple actor wchich always responds when receive object Data and has own receive block wrapped in LoggingReceive, so I should see logs when message is receiving by actor
and i test it using (I think simple code)
class SampleStarngeTest extends WordSpec with ThisAppTestBase with OneInstancePerTest
with routeTestingSugar {
val url = "/firstPath/"
implicit val routeTestTimeout = RouteTestTimeout(5 seconds)
def postTest(data: String) = Post(url).withJson(data) ~> routes
"posting" should {
"pass" when {
"data is valid and comes from the identified user" in {
postTest(correctData.copy(createdAt = System.currentTimeMillis()).asJson) ~> check {
print(entity)
status shouldBe Created
}
}
"report is valid and comes from the anonymous" in {
postTest(correctData.copy(createdAt = System.currentTimeMillis(), adid = "anonymous").asJson) ~> check {
status shouldBe Created
}
}
}
}
}
and behavior:
When I run either all tests in package (using Intellij Idea 14 Ultimate) or sbt test I encounter the same results
one execution -> all tests pass
and next one -> not all pass, this which not pass I can see:
1. fail becouse Request was neither completed nor rejected within X seconds ( X up tp 60)
2. system console output from route from line post(handleWith { (data: Data) =>{ println("receiving data"), so code in handleWith was executed
3. ask timeout exception from route code, but not always (among failed tests)
4. no logs from actor LoggingReceive, so actor hasn't chance to respond
5. when I rerun teststhe results are even different from the previous
Is there problem with threading? or test modules, thread blocking inside libraries? or sth else? I've no idea why it isn't work :(

Related

ScalaTest asserting multiple futures using AsyncFunSuiteLike

I've been trying to perform a test that uses a mock Http server to respond and a function that returns a Future[String] or an Exception if the Http server response isn't 200.
I'm trying to achieve a test without using Awaits, but instead AsyncFunSuiteLike.
However the following test seems impossible to resolve without doing it synchronously:
test("Error responses") {
Future.sequence {
NanoHTTPD.Response.Status.values().toList.filter(status => status.getRequestStatus >= 400).map {
status => {
httpService.setStatusCode(status)
val responseBody = s"Request failed with status $status"
httpService.setResponseContent(responseBody)
val errorMessage = s"Error response (${status.getRequestStatus}) from http service: $responseBody"
recoverToExceptionIf[ServiceException] {
myObject.httpCall("123456")
}.map {
ex => assert(ex.getMessage === errorMessage)
}
}
}
}.map(assertions => assert(assertions.forall(_ == Succeeded)))
}
Basically the problem is that when the Futures are tested, the NanoHTTPD is set to the last valued set in the map, so all ex.getMessage are the same. If I run those status codes one by one I do get the desired results, but, is there a way to perform all this in one single Async test?
From the looks of it, NanoHTTPD is stateful, so you have a race between the .set... calls and the .httpCall.
If you can spin up a new httpService within each Future, then you should be able to parallelize the tests (unless the state in question would be shared across instances, in which case you're likely out of luck).
So you'd have something like (replace Status with the type of status in your code and HTTPService with the type of httpService):
// following code composed on the fly and not run through the compiler...
def spinUpHTTPService(status: Status, body: String): Future[HTTPService] = {
// insert the code outside of the test which creates httpService
httpService.setStatusCode(status)
httpService.setResponseContent(body)
httpService
}
test("Error responses") {
Future.sequence(
NanoHTTPD.Response.Status.values().toList.filter(status => status.getRequestStatus >= 400).map { status =>
spinUpHTTPService(status, s"Request failed with status $status")
.flatMap { httpService =>
val errorMessage = s"Error response (${status.getRequestStatus}) from http service: $responseBody"
recoverToExceptionIf[ServiceException] {
myObject.httpCall("123456")
} map {
ex => assert(ex.getMessage === errorMessage)
}
} // Future.flatMap
} // List.map
).map { assertions => assertions.forAll(_ == Succeeded) }
}

Spray route rejections

I am building some custom directives with Spray and I find a problem:
When a route is rejected I thought that it was immediately completed with a rejection. However it is not and it tries to complete the inner route. For example, in this code:
path("users") {
post {
entity(as[User]){
user =>
directive_always_reject(){
println("Hello")
complete(200, "Hello")
}
}
}
}
The "hello" is always printed, even if the directive is rejected.
I always thought that when a route is rejected it does not continue to inner routes (or at least is how I understand it)
Did I misunderstand something with Spray or there is a bug somewhere in my code?
Thanks you!
[UPDATE 1]
An implementation of directive_always_reject() could be:
def directive_always_reject[T]() : Directive0 = {
reject(
new ValidationRejection("Some error")
)
}
[UPDATE 2]
I see that a solution could be put the println inside the complete function.
path("users") {
post {
entity(as[User]){
user =>
directive_always_reject(){
complete {
println("Hello")
"Hello"
}
}
}
}
}
However this solution does not apply to me because in my real code I pass the RequestContext to another actor who is the one that completes the request.

Consuming a service using WS in Play

I was hoping someone can briefly go over the various ways of consuming a service (this one just returns a string, normally it would be JSON but I just want to understand the concepts here).
My service:
def ping = Action {
Ok("pong")
}
Now in my Play (2.3.x) application, I want to call my client and display the response.
When working with Futures, I want to display the value.
I am a bit confused, what are all the ways I could call this method i.e. there are some ways I see that use Success/Failure,
val futureResponse: Future[String] = WS.url(url + "/ping").get().map { response =>
response.body
}
var resp = ""
futureResponse.onComplete {
case Success(str) => {
Logger.trace(s"future success $str")
resp = str
}
case Failure(ex) => {
Logger.trace(s"future failed")
resp = ex.toString
}
}
Ok(resp)
I can see the trace in STDOUT for success/failure, but my controller action just returns "" to my browser.
I understand that this is because it returns a FUTURE and my action finishes before the future returns.
How can I force it to wait?
What options do I have with error handling?
If you really want to block until feature is completed look at the Future.ready() and Future.result() methods. But you shouldn't.
The point about Future is that you can tell it how to use the result once it arrived, and then go on, no blocks required.
Future can be the result of an Action, in this case framework takes care of it:
def index = Action.async {
WS.url(url + "/ping").get()
.map(response => Ok("Got result: " + response.body))
}
Look at the documentation, it describes the topic very well.
As for the error-handling, you can use Future.recover() method. You should tell it what to return in case of error and it gives you new Future that you should return from your action.
def index = Action.async {
WS.url(url + "/ping").get()
.map(response => Ok("Got result: " + response.body))
.recover{ case e: Exception => InternalServerError(e.getMessage) }
}
So the basic way you consume service is to get result Future, transform it in the way you want by using monadic methods(the methods that return new transformed Future, like map, recover, etc..) and return it as a result of an Action.
You may want to look at Play 2.2 -Scala - How to chain Futures in Controller Action and Dealing with failed futures questions.

Execute some logic asynchronously in spray routing

Here is my simple routing application:
object Main extends App with SimpleRoutingApp {
implicit val system = ActorSystem("my-system")
startServer(interface = "0.0.0.0", port = System.getenv("PORT").toInt) {
import format.UsageJsonFormat._
import spray.httpx.SprayJsonSupport._
path("") {
get {
complete("OK")
}
} ~
path("meter" / JavaUUID) {
meterUUID => pathEnd {
post {
entity(as[Usage]) {
usage =>
// execute some logic asynchronously
// do not wait for the result
complete("OK")
}
}
}
}
}
}
What I want to achieve is to execute some logic asynchronously in my path directive, do not wait for the result and return immediately HTTP 200 OK.
I am quite new to Scala and spray and wondering if there is any spray way to solve this specific problem. Otherwise I would go into direction of creating Actor for every request and letting it to do the job. Please advice.
There's no special way of handling this in spray: simply fire your async action (a method returning a Future, a message sent to an actor, whatever) and call complete right after.
def doStuffAsync = Future {
// literally anything
}
path("meter" / JavaUUID) { meterUUID =>
pathEnd {
post {
entity(as[Usage]) { usage =>
doStuffAsync()
complete("OK")
}
}
}
}
Conversely, if you need to wait for an async action to complete before sending the response, you can use spray-specific directives for working with Futures or Actors.

How can one verify messages sent to self are delivered when testing Akka actors?

I have an Actor that is similar to the following Actor in function.
case class SupervisingActor() extends Actor {
protected val processRouter = //round robin router to remote workers
override def receive = {
case StartProcessing => { //sent from main or someplace else
for (some specified number of process actions ){
processRouter ! WorkInstructions
}
}
case ProcessResults(resultDetails) => { //sent from the remote workers when they complete their work
//do something with the results
if(all of the results have been received){
//*********************
self ! EndProcess //This is the line in question
//*********************
}
}
case EndProcess {
//do some reporting
//shutdown the ActorSystem
}
}
}
}
How can I verify the EndProcess message is sent to self in tests?
I'm using scalatest 2.0.M4, Akka 2.0.3 and Scala 1.9.2.
An actor sending to itself is very much an intimiate detail of how that actor performs a certain function, hence I would rather test the effect of that message than whether or not that message has been delivered. I’d argue that sending to self is the same as having a private helper method on an object in classical OOP: you also do not test whether that one is invoked, you test whether the right thing happened in the end.
As a side note: you could implement your own message queue type (see https://doc.akka.io/docs/akka/snapshot/mailboxes.html#creating-your-own-mailbox-type) and have that allow the inspection or tracing of message sends. The beauty of this approach is that it can be inserted purely by configuration into the actor under test.
In the past, I have overridden the implementation for ! so that I could add debug/logging. Just call super.! when you're done, and be extra careful not to do anything that would throw an exception.
I had the same issue with an FSM actor. I tried setting up a custom mailbox as per the accepted answer but a few minutes didn't get it working. I also attempted to override the tell operator as per another answer but that was not possible as self is a final val. Eventually I just replaced:
self ! whatever
with:
sendToSelf(whatever)
and added that method into the actor as:
// test can override this
protected def sendToSelf(msg: Any) {
self ! msg
}
then in the test overrode the method to capture the self sent message and sent it back into the fsm to complete the work:
#transient var sent: Seq[Any] = Seq.empty
val fsm = TestFSMRef(new MyActor(x,yz) {
override def sendToSelf(msg: Any) {
sent = sent :+ msg
}
})
// yes this is clunky but it works
var wait = 100
while( sent.isEmpty && wait > 0 ){
Thread.sleep(10)
wait = wait - 10
}
fsm ! sent.head