In 30 minutes I would like to show: 1. Why is it worth to spend some time and learn Gatling - a tool for integration/performance test of your web application? 2. Under what circumstances it is necessary to have Gatling in your toolbox? 3. What are Gatling cons and what kind of problems can you expect? For sure there is no silver bullet in testing tools area, but you will definitely love Gatling DSL.

1. Performance tests with
Gatling
Andrzej Ludwikowski

3. Performance tests - why so hard?
Simulate production as close as possible:
● hardware
○ CPU, RAM, storage, ...
● software
○ OS, Virtualization, DBs, …
● load
● isolation

4. Performance tests - why so hard?
Necessary to have:
● infrastructure
● monitoring
● logging

5. Performance tests - why so hard?
Lies, damned lies, and statistics:
● arithmetic mean = 2.9
● median = 1
● standard deviation = 6 (only for normal distribution)
Use:
● percentiles
○ 50 = 1
○ 70 = 1
○ 90 = 2.9
○ 95 = 11.45
○ 99 = 18.29
Check percentiles implementation!

6. Performance tests - why so hard?
● Tests…

7. Gatling

8. Gatling

9. Why Gatling?
● non-blocking, asynchronous stack (scala, akka, netty)
● scala !!!111oneoneone (maven, sbt support)
● DSL
● recorder
● math is good
● reports
● integration & performance tests

10. Gatling DSL
class BasicSimulation extends Simulation {
val httpConf = http
.baseURL("http://computer-database.gatling.io")
.acceptHeader("text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")
.acceptEncodingHeader("gzip, deflate")
.acceptLanguageHeader("en-US,en;q=0.5")
.userAgentHeader("Mozilla/5.0 (Macintosh; X 10.8; rv:16.0) Gecko/20100101 Firefox/16.0")
val firstScenario = scenario("First Scenario Name")
.exec(http("Request name").get("/"))
.pause(7)
setUp(firstScenario.inject(atOnceUsers(1)).protocols(httpConf))
}

11. Gatling DSL
class FirstScenarioV2 extends MySimulation{
val firstScenario = scenario("First Scenario Name")
.exec(http("Go to root page").get("/"))
.pause(7 seconds)
setUp(firstScenario.inject(atOnceUsers(1)).protocols(httpConf))
}

12. Gatling DSL
import io.gatling.core.Predef._
import io.gatling.http.Predef._
class FirstScenarioV2 extends MySimulation{
val firstScenario = scenario("First Scenario Name")
.exec(http("Go to root page").get("/"))
.pause(7 seconds)
setUp(firstScenario.inject(atOnceUsers(1)).protocols(httpConf))
}

13. Gatling DSL
class ComplexScenario extends MySimulation{
val complexScenario = scenario("Complex demo scenario")
.exec(http("request_1").get("/")).pause(7)
.exec(http("request_2").get("/computers?f=macbook")).pause(2)
.exec(http("request_3").get("/computers/6")).pause(3)
.exec(http("request_4").get("/")).pause(2)
.exec(http("request_5").get("/computers?p=1")).pause(670 milliseconds)
.exec(http("request_6").get("/computers/new")).pause(1)
.exec(http("request_7")
.post("/computers")
.formParam("name", "MyComputer").formParam("introduced", "2012-05-30").formParam("company", "37"))
setUp(complexScenario.inject(atOnceUsers(1)).protocols(httpConf))
}

14. Gatling DSL
class ComplexScenarioV2 extends MySimulation {
val complexScenario = scenario("Complex demo scenario")
.exec(goToRootPage).pause(7)
.exec(searchFor("macbook")).pause(2)
.exec(positionAt(6)).pause(3)
.exec(goToRootPage).pause(2)
.exec(goToPage(1)).pause(670 milliseconds)
.exec(openNewComputerForm).pause(1)
.exec(addNewComputer)
setUp(complexScenario.inject(atOnceUsers(1)).protocols(httpConf))
}

15. Gatling DSL
class ComplexScenarioV3 extends MySimulation {
val search = exec(goToRootPage).pause(7)
.exec(searchFor("macbook")).pause(2)
.exec(positionAt(6)).pause(3)
val addComputer = exec(goToRootPage).pause(2)
.exec(goToPage(1)).pause(670 milliseconds)
.exec(openNewComputerForm).pause(1)
.exec(addNewComputer)
val complexScenario = scenario("Complex demo scenario").exec(search, addComputer)
setUp(complexScenario.inject(atOnceUsers(1)).protocols(httpConf))
}

16. Gatling DSL - checks
scenario("DSL demo")
.exec(http("go to page")
.get("/computers")
.check(status.is(200))
.check(status.in(200 to 210))

17. Gatling DSL - checks
scenario("DSL demo")
.exec(http("go to page")
.get("/computers")
.check(regex("computers")
.find(1)
.exists)
https://www.pinterest.com/pin/491666484294006138/

18. Gatling DSL - checks
scenario("First Scenario Name")
.exec(http("Request name")
.get("/computers")
.check(jsonPath("$..foo.bar[2].baz").ofType[String].notExists)
.check(xpath("//input[@id='text1']/@value").is("test"))
.check(css("...").transform(_.split('|').toSeq).is(Seq("1", "2")))

19. Gatling DSL - checks
scenario("DSL demo")
.exec(http("Authorize")
.get("/auth")
.check(regex("token").find(1).exists
.saveAs("authorizationToken")))
.exec(http("Authorized resource")
.get("/authorized_resource?token=${authorizationToken}"))

20. Gatling DSL - looping
repeat(5, "i") {
exec(goToPage("${i}".toInt))
.pause(1)
}
● repeat
● foreach
● during
● asLongAs
● forever
https://blog.hubspot.com/blog/tabid/6307/bid/32019/Why-Every-Marketer-Needs-Closed-Loop-Reporting.aspx#sm.0005lrqj811waf3ntmn1cul3881gr

21. Gatling DSL - polling
exec(
polling
.every(10 seconds)
.exec(searchFor("thinkpad"))
)
http://www.firmus-solutions.com/terms-conditions.html

22. Gatling DSL - conditions
doIf(session => session("user").as[String].startsWith("admin")) {
exec(goToAdminPage)
}
● doIf
● doIfEquals
● doIfOrElse
● doSwitch
● doSwitchOrElse
● randomSwitch
https://en.wikipedia.org/wiki/Decision_tree

23. Gatling DSL - error management
exec(sendMoney)
.tryMax(10){
exec(checkIfMoneyReceived)
}
● tryMax
● exitBlockOnFail
● exitHereIfFailed
Sender Receiver
Kafka

24. Gatling DSL - setup
setUp(myScenario
.inject(
nothingFor(4 seconds),
atOnceUsers(10),
rampUsers(10) over (5 seconds))
.protocols(httpConf))
.maxDuration(10 minutes)
● constantUsersPerSec
● rampUsersPerSec
● splitUsers
● heavisideUsers

25. Gatling DSL - setup
setUp(myScenario
.inject(atOnceUsers(10))
.protocols(httpConf))
.assertions(
global.responseTime.max.lt(50),
global.failedRequests.percent.is(0)
)
http://englishthroughlaxas.blogspot.com/2015/07/531-24-expression-of-assertion-emphasis.html

26. Gatling DSL - setup
setUp(myScenario
.inject(atOnceUsers(10))
.protocols(httpConf))
.throttle(
reachRps(100) in (30 second),
holdFor(1 minute),
jumpToRps(50),
holdFor(2 hours)
)

27. Gatling DSL - feeders
val companies = List("apple", "lenovo", "hp")
val feeder = Iterator.continually(
Map("company" -> companies(Random.nextInt(companies.size))))
val searching = scenario("Searching")
.feed(feeder)
.exec(searchFor("${company}"))
● RecordSeqFeederBuilder
● CSV
● JSON
● JDBC
● Sitemap
● Redis
● … http://favim.com/orig/201104/23/Favim.com-22725.jpg

28. Gatling DSL - resource inferring
val httpConf = http
.baseURL("http://computer-database.gatling.io")
.acceptHeader("...")
.acceptEncodingHeader("...")
.acceptLanguageHeader("...")
.inferHtmlResources()
.userAgentHeader("...")

29. Gatling DSL - other goodies
● Custom validators
● HTTP
○ SSL
○ SSE (Server Sent Event)
○ basic cookies support
● WebSocket
● JMS
● Pluginable architecture:
○ cassandra plugin
○ kafka plugin
○ rabbitMQ
○ AMQP

30. Gatling DSL - logging/debugging
● logging ALL HTTP request and responses
<logger name="io.gatling.http.ahc" level="TRACE" />
<logger name="io.gatling.http.response" level="TRACE" />
● logging ONLY FAILED HTTP request and responses
<logger name="io.gatling.http.ahc" level="DEBUG" />
<logger name="io.gatling.http.response" level="DEBUG" />

31. Gatling DSL - reporting
================================================================================
---- Global Information --------------------------------------------------------
> request count 10 (OK=10 KO=0 )
> min response time 40 (OK=40 KO=- )
> max response time 177 (OK=177 KO=- )
> mean response time 55 (OK=55 KO=- )
> std deviation 41 (OK=41 KO=- )
> response time 50th percentile 42 (OK=42 KO=- )
> response time 75th percentile 43 (OK=43 KO=- )
> response time 95th percentile 117 (OK=117 KO=- )
> response time 99th percentile 165 (OK=165 KO=- )
> mean requests/sec 0.909 (OK=0.909 KO=- )
---- Response Time Distribution ------------------------------------------------
> t < 800 ms 10 (100%)
> 800 ms < t < 1200 ms 0 ( 0%)
> t > 1200 ms 0 ( 0%)
> failed 0 ( 0%)
================================================================================

32. Gatling DSL - distributed
IT system

33. Gatling DSL - distributed
● manually
● Gatling FrontLine
● Flood.io
IT system

35. About me
➔
➔ aludwikowski.blogspot.com
➔ github.com/aludwiko
➔ @aludwikowski