In JMeter how do I set multiple dynamic variables in User Parameters or CSV Data Set Config

0
votes

Very new to JMeter (and a long time Stack Overflow listener but first time caller so take it easy on me) so any help would be appreciated.

I am trying to set up a JMeter test that uses multiple dynamically generated access tokens to run across scenarios. I currently have a set of data using the CSV Data Set Config containing login credentials of a user's email and password for example:

[email protected],password1
[email protected],password2

Next I send a HTTP POST request to the Login service which generates an accessToken. Then, I am using the JSON Extractor to grab the generated accessToken. After that I am using the BeanShell Assertion to store the accessToken property/variable.

My issue seems to lie here in this last step since it will only store the last generated variable instead of each of the generated accessTokens. I want to be able to store/overwrite the grabbed accessToken for each email password combination. I would like it to modify/populate the CSV file like this:

[email protected],password1,accessToken1
[email protected],password2,accessToken2

I have also tried using the Pre Processor > User Parameters

Screen shot of User Parameters

I would like to have the "userBearerToken" variable update/overwrite along with the tests, but I cannot find a way to do so or if this can even currently be done.

I'm finding it difficult to word what I am trying to ask, but basically I want to store multiple dynamically generated variables (accessTokens that change and time out) and use them in other tests. I don't care which component can handle this (either the CSV or User Parameter), but I need to be able to store these variables with their corresponding email password credentials.

1
jmeterperformance-testingload-testing

1 Answers

0
votes

If you want to store the accessToken value into a JMeter property for using in other Thread Group(s) be aware that properties are global for the whole JVM and remain until JMeter is restarted so if you define a single accessToken property - each JMeter Thread (or iteration) will overwrite the value.

The solution is to use current thread (or iteration) number as prefix or postfix, this can be done using either __${__threadNum} function or relevant JMeter Variable depending on how iteration is defined or both.

Example setup:

  1. In first thread group: ${__setProperty(access_token_${__threadNum},bar,)}
  2. In second thread group: ${__P(access_token_${__threadNum},)}

Demo:

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If you want to save the values into a file writing into the current one is not the best idea as you can (and most probably will) get malformed file due to a form of a race condition. So I would recommend using Sample Variables property instead.

If you add the next line to user.properties file:

sample_variables=email,password,accessToken

JMeter will store the variables named ${email}, ${password}, and ${accessToken} along with their values in the .jtl results file which is basically CSV file which can be re-used anywhere else.

However if you have a requirement to store only the credentials and the token you can go for the Flexible File Writer plugin and configure it to save the aforementioned variables values into a separate file, the relevant configuration would be as simple as:

variable#0,variable#1,variable#2

enter image description here

You can install Flexible File Writer plugin using JMeter Plugins Manager

enter image description here