TestWorks Conf Performance testing made easy with gatling - Guillaume Corré

© Gatling 2015. All rights reserved.

Requirements

Background in programming1. Object oriented language mostly2. Functional programming is a plus, but optional

Experience1. Gatling?2. Scala?

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Load Testing Done Righthttp://gatling.io

Guillaume Corré @notdryft

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Workshop Schedule

1. Architecture2. Usage3. Exercises

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Workshop Schedule

1. Architecture 2. Usage3. Exercises

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Gatling: Architecture

Designed for :1. Complex use cases2. High Performance3. Maintainability

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High PerformanceOptimize thread usage:

1. Non Blocking IO

2. Message oriented orchestration

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High Performance

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MaintainabilityCode

1. Real programming language2. DSL3. API

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MaintainabilityWhy?

1. Versioning2. Refactoring3. Peer review4. Composition

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Maintainability

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class Simple extends Simulation { val scn = scenario("simple") .exec( http("home") .get("http://gatling.io") .check(status.is(200)))

setUp( scn.inject( atOnceUsers(1)))}


Workshop Schedule

1. Architecture2. Usage 3. Exercises

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Gatling: Usage

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Usage: DSL

Extensive documentation:http://gatling.io/#/docs

Cheat-sheet:http://gatling.io/docs/2.1.7/cheat-sheet.html

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http://gatling.io/#/docs

http://gatling.io/docs/2.1.7/cheat-sheet.html


Usage: Very Fast Track

Step 1: Create a Simulation class

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import io.gatling.core.Predef._import io.gatling.http.Predef._

import scala.concurrent.duration._

class Simple extends Simulation {

}



Step 2: Create a Scenario

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import …


val scn = scenario("simple")}



Step 3: Chain Actions

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import …


val scn = scenario("simple") .exec( http("home") .get("http://gatling.io"))}



Step 4: Check your requests are fine

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import …


val scn = scenario("simple") .exec( http("home") .get("http://gatling.io") .check(status.is(200))}



Step 5: Set up and inject users

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import …


val scn = scenario("simple") .exec( http("home") .get("http://gatling.io") .check(status.is(200))

setUp(scn.inject(atOnceUsers(1)))}



Step 6: Make things dynamic

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// Set up virtual users with feedersfeed(csv("credentials.csv"))




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// Capture response data with checkshttp("request") .get("url") .check(css("someSelector").saveAs("someVariable"))




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// Craft requests with the Expression Languagehttp("request") .get("/foo?bar=${someVariable}")




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// Use functionsexec { session => println(session) session}



Expressions

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type Expression[T] = Session => Validation[T]


Workshop Schedule

1. Architecture2. Usage3. Exercises

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Workshop

4 exercises1. Ranged from (almost) easy to difficult2. Each pinpoint different specifics of Gatling

Urlbit.ly/gatling-workshop

Documentation reminderhttp://gatling.io/#/docs


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http://bit.ly/gatling-workshop

http://gatling.io/#/docs



Exercise 1:1. First RequestWhat happens if you don't do any checks?

1. Gatling adds a status check by default

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Exercise 1:1. First RequestAre there any defaults? If so, which?

1. status.in2. All statuses of the 20x family3. 304

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Exercise 1:3. ChecksWhich check should you use to fetch the title ?

1. Regex1. Most the time harder to maintain2. Still does the job pretty well

2. XPath1. HTML needs to be strict and well formed

3. CSS is easy to read and fast1. css("#logo-section a", "title")

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Exercise 1:3. ChecksWhat happens when a check matches more than a single element?

1. exists by default2. And, if you don’t specify a fetch method but try to save,

Gatling will add a find(0) before saveAs

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Exercise 1:4. Information retrieval

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Which check should you use to fetch the menu links ?1. css("#main-menu-inner > ul > li > a", "href")


Exercise 1:4. Information retrievalHow can you save all matches?

1. findAll

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Exercise 1:4. Information retrievalHow can you access the “menuLinks” attribute?

1. Use the exec { session => … } syntax2. session(“menuLinks”) for extraction3. Then, either

1. as[Type]2. asOption[Type]3. validate[Type]

4. Validate recommended unless you know what you are doing

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Exercise 1:4. Iterate over menu linksWhich DSL element should you use?

1. foreach2. Takes an Expression[String] as its first argument

1. Which is a function of Session to Validation[String]3. Gatling does the EL conversion for you

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Exercise 1:4. Iterate over menu linksHow do think it works behind the hood?

1. Iterate over each element2. Put current element into the session as an attribute3. Run the action block with the new session

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Exercise 2:1. Fetch the login pageWhich baseURL should you use?

1. Gatling doesn’t add a / before concatenating2. One of the following

1. baseURL(“https://github.com”) and get(“/login”)2. baseURL(“https://github.com/“) and get(“login”)

3. Prefer the first one

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https://github.com

https://github.com/


Exercise 2:1. Fetch the login pageWhich check should you use?

1. The general idea is to make sure you are on the page you requested

2. css(".auth-form form h1").is("Sign in")

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Exercise 2:2.1. Performing the loginWhich request should you do?

1. /sessionWhich HTTP method does it need to use?

2. POST

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Exercise 2:2.2. Specifying additional parametersDo you think these are generated or provided?

1. Generated by Github, provided in the HTML.Where can you fetch thoses?

2. Add a check to the previous request3. css(".auth-form form input[name='authenticity_token']",

“value").saveAs("authenticityToken")

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Exercise 2:3. ChecksWhich checks should you use to be sure you are logged in?

1. Check for content, titles, css, etc.2. css(“.logged_in”)3. exists is a default

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Exercise 2:4. Feeding the credentialsWhich feeder file format could you use?

1. Multiple formats are handled by Gatling1. CSV, TSV, etc.

2. Just beware of malformed files

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Exercise 2:4. Feeding the credentialsHow does the session interact with the feeder?

1. A feeder outputs lines of CSV (and else) files into the session

2. One line per user, with different methods of retrieval1. Queue, failure when reading is over2. Random3. Shuffle, which is a shuffle + queue4. Circular

3. If you want more, you can skip the feeding to Gatling and fetch the records yourself

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Exercise 3:1. Create gistThink of multiple ways to load the templates

1. StringBody2. RawFileBody3. ELFileBody, with parsed content

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Exercise 3:1. Create gistWhich one is better in this case?

1. All are good2. Still, scala can handle string template pretty well3. => StringBody

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Exercise 4:Part 1. 1. Start simpleIs using java.util.Random a good idea in this case?What could happen if you do?

1. Random is synchronized2. Multiples threads would block each other when fetching3. ThreadLocalRandom is not4. It creates a single Random for each Thread, resolving

conflicts

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Exercise 4:Part 1. 4. A twistHow does Gatling execute requests?

1. Each requests are launched in sequence2. They cannot overlap3. And cannot be launched asynchronously

How should we proceed instead?

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Exercise 4:Part 1. 4. A twistHow does Gatling execute requests?

1. Each requests are launched in sequence2. They cannot overlap3. And cannot be launched asynchronously

How should we proceed instead?4. We can use the resources mechanism5. Not its purpose, but it will work

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Exercise 4:Part 1I. 2. Making the queriesIs the number of tiles requested really fixed?

1. What about edges ?2. Will reduce the number of tiles3. We can reduce the bounds, excluding the edges

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Exercise 4:Part 1I. 2. Making the queriesMixing Gatling’s EL and Scala’s String Macro

1. This a Gatling EL: “${variableName}”2. Theses are Scala Macros:

1. s”$variableName”2. s”${variableName}

How?

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Exercise 4:Part 1I. 2. Making the queriesMixing Gatling’s EL and Scala’s String Macro

1. This a Gatling EL: “${variableName}”2. Theses are Scala Macros:

1. s”$variableName”2. s”${variableName}

How?1. Escape Gatling’s EL when in a Scala String Macro

1. s”$${gatlingVariable}/${otherVariable}”2. will output “${gatlingVariable}/variableContent”

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Workshop

Solutions1. Not available yet

Urlbit.ly/gatling-workshop-solutions

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http://bit.ly/gatling-workshop-solutions


http://gatling.io

http://github.com/gatling/gatling

@GatlingTool

TestWorks Conf Performance testing made easy with gatling - Guillaume Corré

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Transcript of TestWorks Conf Performance testing made easy with gatling - Guillaume Corré