How to write Extracted Data in to A File In Gatling - performance-testing

Question

I am using Gatling for load testing. When I am creating Customer profiles , Customer IDs will be generated. I am able to extract the customer ID and saving in to session variables.
But How to store these values in to a Text file.
please help me.

Answer 1

There's several ways to achieve that.
If you're familiar with Scala, you can:
open a file in your simulation
write into it in a exec(function): https://github.com/excilys/gatling/wiki/Session#wiki-functions
close the file (either register an ActorSystem shutdown hook, or use Gatling 2 snapshot after hook: https://github.com/excilys/gatling/issues/1475)
If this is too complex for you, the most simple way is to use logback:
declare a logger in your simulation with a special name
configure logback so this logger outputs in a dedicated FileAppender
use a pattern that just logs the message
Regarding the second solution, check the logback documentation: http://logback.qos.ch/documentation.html

Answer 2

In the example below I'm saving the extracted NumberIDs out of the SOAP response and then save them into the numbersIDs.csv file so that it can be fed into another Request.
//Variables to store the extracted values of the response
var numberIDs : Seq[String] = _
//Java Writer
val numberIDs_writer = {
val fos = new java.io.FileOutputStream("numbersIDs.csv")
new java.io.PrintWriter(fos,true)
}
val scn = scenario("basicSimulation")
.exec(http("Request_One")
.post("/services")
.body(StringBody(inputXMLpayLoad))
.headers(Request_One_Header)
.check(bodyString.saveAs("Request_Response")) //Save the response in a variable called Request_Response
.check((status.is(200)))
//Extract all numberIDs of the SOAP response
.check(regex("""<NumberId>([\d]+)</NumberId>""")
.findAll
.transform { string => numberIDs = string; string }
.saveAs("numberIDs")))
//Save variable numberIDs into the csv file
.foreach("${numberIDs}", "id") {
exec(session => {
numberIDs_writer.println(session("id").as[String])
session
})
}

Answer 3

Since 2.0.0-M1, infoExtractor hook takes a Session parameter:
https://github.com/excilys/gatling/issues/1004
There's also a builtin that adds the Session content to simulation.log records when the request fails.
https://github.com/excilys/gatling/commit/b7b6299c658d0aa1b88971208eb0c98a9808e37f
You can adapt this example if you just want to log with logback.
class MySimulation extends Simulation with Logging {
def logSessionOnFailure(status: RequestStatus, session: Session, request: Request, response: ExtendedResponse): List[String] = {
if (status == KO) logger.error(session)
Nil
}
val httpConf = http
...
.extraInfoExtractor(logSessionOnFailure)
...
}

Answer 4

Another possibility (not tested, but could work) is to use response transformer (call .transformResponse after .post). In the transformer body you would get a response object from which you can extract the generated ID and append it into a file, collection, etc.. Then just return the original response as the transformation result. This is however not a very nice solution from the design point of view, because your transformation has a side effect.