JMeter & python gotchas

Aodan   jmeter, python

Using python is easy with JMeter, which doesn’t mean one should not be careful with how it’s implemented. Here you will find out about examples, how to deal with it.

Datetime Objects

There are some things to watch out for when using jython/python in JSR223 code in Jmeter.

As Jython is a java implementation of Python you may come across some “Type” bugs.

Let’s look at the datetime object.

If we wanted to create 2 variables for our script, 1 being the current datetime and the other being 10 days from now.
This is a common case when scripting for airline flights.

In native Python we can just do something like:

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import datetime

date = datetime.datetime.now()
date_plus_10_days = date + datetime.timedelta(days=10)
print("current_date is %s, date_plus_10_days is %s" % (date, date_plus_10_days))

current_date is 2019-03-06 13:06:30.941109, date_plus_10_days is 2019-03-16 13:06:30.941109

However when using this in jmeter JSR223 code we get the following error.

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This is because of a “TypeError”. When Jython assigns a datetime object to a variable, it transforms it to a java.sql.Timestamp object.

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So, in order to use datetime objects in jython, you need to use them immediately and not assign them to a variable.

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This makes the code less eloquent, but it looks like this “bug/feature” won’t be fixed, so you will have to use this workaround.

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