I'm new to Gatling. I'm trying to understand how to work with the Loop statements.
I have a code example:
private def createGame: ChainBuilder = exec(
exec(session => session.set("number", "1"))
.asLongAsDuring(true, 15.seconds) {
exec(session => { //1
val k1 = session("number") //6
val ORDER_ID = session("ORDER_ID") //7
println(s"I am verifying something ${k1}, ${ORDER_ID}") //8
session //9
})
.exec(buildSessions) //2
.exec(http("Get specific game") //4
.get("/videogames/${number}") //5
.check(status.in(200 to 210))) //3
}
)
I'm having hard time to understand the order of calls inside the asLongAsDuring loop. I marked the lines with comments, this is how the test runs when I am debuging it (starting with //1).
Could some explain why the code inside the loop doesn't work line by line?
Thanks.
p.s. Seems like it's the same for all loop statements.
You're confusing build time and runtime.
First, Gatling loads the Simulation and builds the builders (such as your ChainBuilder) and generate the actual Scenario, then the different virtual users execute it and in particular execute your functions.
Note: your Session API is wrong, please check the documentation.
Related
I am new to scala and spark both .
I have a code in scala which executes quieres in while loop one after the other.
What we need to do is if a particular query takes more than a certain time , for example # 10 mins we should be able to stop the query execution for that particular query and move on to the next one
for example
do {
var f = Future(
spark.sql("some query"))
)
f onSucess {
case suc - > println("Query ran in 10mins")
}
f failure {
case fail -> println("query took more than 10mins")
}
}while(some condition)
var result = Await.ready(f,Duration(10,TimeUnit.MINUTES))
I understand that when we call spark.sql the control is sent to spark which i need to kill/stop when the duration is over so that i can get back the resources
I have tried multiple things but I am not sure how to solve this.
Any help would be welcomed as i am stuck with this.
I am trying to loop over inputs and process them to produce scores.
Just for the first input, I want to do some processing that takes a while.
The function ends up returning just the values from the 'else' part. The 'if' part is done executing after the function returns the value.
I am new to Scala and understand the behavior but not sure how to fix it.
I've tried inputs.zipWithIndex.map instead of foreach but the result is the same.
def getscores(
inputs: inputs
): Future[Seq[scoreInfo]] = {
var scores: Seq[scoreInfo] = Seq()
inputs.zipWithIndex.foreach {
case (f, i) => {
if (i == 0) {
// long operation that returns Future[Option[scoreInfo]]
getgeoscore(f).foreach(gso => {
gso.foreach(score => {
scores = scores.:+(score)
})
})
} else {
scores = scores.:+(
scoreInfo(
id = "",
score = 5
)
)
}
}
}
Future {
scores
}
}
For what you need, I would drop the mutable variable and replace foreach with map to obtain an immutable list of Futures and recover to handle exceptions, followed by a sequence like below:
def getScores(inputs: Inputs): Future[List[ScoreInfo]] = Future.sequence(
inputs.zipWithIndex.map{ case (input, idx) =>
if (idx == 0)
getGeoScore(input).map(_.getOrElse(defaultScore)).recover{ case e => errorHandling(e) }
else
Future.successful(ScoreInfo("", 5))
})
To capture/print the result, one way is to use onComplete:
getScores(inputs).onComplete(println)
The part your missing is understanding a tricky element of concurrency, and that is that the order of execution when using multiple futures is not guaranteed.
If your block here is long running, it will take a while before appending the score to scores
// long operation that returns Future[Option[scoreInfo]]
getgeoscore(f).foreach(gso => {
gso.foreach(score => {
// stick a println("here") in here to see what happens, for demonstration purposes only
scores = scores.:+(score)
})
})
Since that executes concurrently, your getscores function will also simultaneously continue its work iterating over the rest of inputs in your zipWithindex. This iteration, especially since it's trivial work, likely finishes well before the long-running getgeoscore(f) completes the execution of the Future it scheduled, and the code will exit the function, moving on to whatever code is next after you called getscores
val futureScores: Future[Seq[scoreInfo]] = getScores(inputs)
futureScores.onComplete{
case Success(scoreInfoSeq) => println(s"Here's the scores: ${scoreInfoSeq.mkString(",")}"
}
//a this point the call to getgeoscore(f) could still be running and finish later, but you will never know
doSomeOtherWork()
Now to clean this up, since you can run a zipWithIndex on your inputs parameter, I assume you mean it's something like a inputs:Seq[Input]. If all you want to do is operate on the first input, then use the head function to only retrieve the first option, so getgeoscores(inputs.head) , you don't need the rest of the code you have there.
Also, as a note, if using Scala, get out of the habit of using mutable vars, especially if you're working with concurrency. Scala is built around supporting immutability, so if you find yourself wanting to use a var , try using a val and look up how to work with the Scala's collection library to make it work.
In general, that is when you have several concurrent futures, I would say Leo's answer describes the right way to do it. However, you want only the first element transformed by a long running operation. So you can use the future return by the respective function and append the other elements when the long running call returns by mapping the future result:
def getscores(inputs: Inputs): Future[Seq[ScoreInfo]] =
getgeoscore(inputs.head)
.map { optInfo =>
optInfo ++ inputs.tail.map(_ => scoreInfo(id = "", score = 5))
}
So you neither need zipWithIndex nor do you need an additional future or join the results of several futures with sequence. Mapping the future just gives you a new future with the result transformed by the function passed to .map().
How do I replace my first conditional with the require function in the context of a Future? Should I wrap the entire inRange method in a Future, and if I do that, how do I handle the last Future so that it doesn't return a Future[Future[List[UserId]], or is there a better way?
I have a block of code that looks something like this:
class RetrieveHomeownersDefault(depA: DependencyA, depB: DependencyB) extends RetrieveHomeowners {
def inRange(range: GpsRange): Future[List[UserId]] = {
// I would like to replace this conditional with `require(count >= 0, "The offset…`
if (count < 0) {
Future.failed(new IllegalArgumentException("The offset must be a positive integer.")
} else {
val retrieveUsers: Future[List[UserId]] = depA.inRange(range)
for (
userIds <- retrieveUsers
homes <- depB.homesForUsers(userIds)
) yield FilterUsers.withoutHomes(userIds, homes)
}
}
}
I started using the require function in other areas of my code, but when I tried to use it in the context of Futures I ran into some hiccups.
class RetrieveHomeownersDefault(depA: DependencyA, depB: DependencyB) extends RetrieveHomeowners {
// Wrapped the entire method with Future, but is that the correct approach?
def inRange(range: GpsRange): Future[List[UserId]] = Future {
require(count >= 0, "The offset must be a positive integer.")
val retrieveUsers: Future[List[UserId]] = depA.inRange(range)
// Now I get Future[Future[List[UserId]]] error in the compiler.
for (
userIds <- retrieveUsers
homes <- depB.homesForUsers(userIds)
) yield FilterUsers.withoutHomes(userIds, homes)
}
}
Any tips, feedback, or suggestions would be greatly appreciated. I'm just getting started with Futures and still having a tough time wrapping my head around many concepts.
Thanks a bunch!
Just remove the outer Future {...} wrapper. It's not necessary. There's no good reason for the require call to go inside the Future. It's actually better outside since then it will report immediately (in the same thread) to the caller that the argument is invalid.
By the way, the original code is wrong too. The Future.failed(...) is created but not returned. So essentially it didn't do anything.
I'm current creating some Gatling simulation to test a REST API. I don't really understand Scala.
I've created a scenario with several exec and pause;
object MyScenario {
val ccData = ssv("cardcode_fr.csv").random
val nameData = ssv("name.csv").random
val mobileData = ssv("mobile.csv").random
val emailData = ssv("email.csv").random
val itemData = ssv("item_fr.csv").random
val scn = scenario("My use case")
.feed(ccData)
.feed(nameData)
.feed(mobileData)
.feed(emailData)
.feed(itemData)
.exec(
http("GetCustomer")
.get("/rest/customers/${CardCode}")
.headers(Headers.headers)
.check(
status.is(200)
)
)
.pause(3, 5)
.exec(
http("GetOffers")
.get("/rest/offers")
.queryParam("customercode", "${CardCode}")
.headers(Headers.headers)
.check(
status.is(200)
)
)
}
And I've a simple Simulation :
class MySimulation extends Simulation {
setUp(MyScenario.scn
.inject(
constantUsersPerSec (1 ) during (1)))
.protocols(EsbHttpProtocol.httpProtocol)
.assertions(
global.successfulRequests.percent.is(100))
}
The application I'm trying to simulate is a multilocation mobile App, so I've prepared a set of samples data for each Locale (US, FR, IT...)
My REST API handles all the locales, therefore I want to make the simulation concurrently execute several instances of MyScenario, each with a different locale sample, to simulate the global load.
Is it possible to execute my simulation without having to create/duplicate the scenario and change the val ccData = ssv("cardcode_fr.csv").random for each one?
Also, each locale has its own load, how can I create a simulation that takes a single scenario and executes it several times concurrently with a different load and feeders?
Thanks in advance.
From what you've said, I think this may be a good approach:
Start by grouping your data in such a way that you can look up each item you want to send based on the current locale. For this, I would recommend using a Map that matches a locale string (such as "FR") to the item that matches that locale for the field you're looking to fill in. Then, at the start of each iteration of the scenario, you just pick which locale you want to use for the current iteration from a list. It would look something like this:
val locales = List("US", "FR", "IT")
val names = Map( "US" -> "John", "FR" -> "Pierre", "IT" -> "Guillame")
object MyScenario {
//These two lines pick a random locale from your list
val random_index = rand.nextInt(locales.length);
val currentLocale = locales(random_index);
//This line gets the name
val name = names(currentLocale)
//Do the rest of your logic here
}
This is a very simplified example - you'll have to figure out how you actually want to retrieve the data from files and put it into a Map structure, as I assume you don't want to hard code every item for every field into your code.
I would like to save a session attribute in a list in my gatling simulation. What am trying to do is to get all the values of my JSON who are defined in a CV file and write it in a file. In my example below "test" is always equal to the value of the first jsonPath.
Here what I am doing:
val scn1 = scenario("[SCENARIO] GET")
.repeat(Nbproduct-1, "counter") (
feed(csv(CSV).circular)
.exec(http("get JSON")
.get(url_1")
.check(jsonPath("""$.${meta_ref}""").find.saveAs("test")))
.pause(1)
.exec(session => {
writer.write("\""+session("meta_cts").as[String]+"\":\"" + session("test").as[String]+"\",\n")
session
}
)
I also tried this but it get the value of the counter...
.check(jsonPath("""$.${meta_ref}""").find.saveAs("""jdd_value("${counter}")""")))
Thanks for the help!
Feeders are shared datasources, so first user will pop the first record, second user the second record, etc...
Then, it's not possible to define checks at runtime (depending on some entries in a file). All DSL components are builders that are only resolved once when the Simulation is loaded.