django-performance-testing 0.2.0

Performance testing tools for Django

Performance testing for Django through your automated tests!

• Setup

• Supported Limits

• Setting Limits

  • Predefined limit points

  • Sample Settings

• Ad-Hoc Limits

• Release Notes

• Contributing

  • Reporting issues/improvements

  • Pull Requests

  • Setting up all Python versions

  • Code of Conduct

Don’t leave performance testing until the end of the project! We have learned already that more frequent feedback on smaller chunks of changes is much better, e.g.: TDD, CI, DevOps, Agile, etc.

This library helps by providing performance testing from the start - integrating it seemlessy into your existing development cycle, without requiring changes to your development workflow.

Unlike regular performance testing tools (ab, tsung, etc.), this libary relies on indirect (proxy) indicators to performence - e.g.: the number of queries executed. It’s a good rule of thumb that the more SQL there is, the slower it will be. And this way “performance” testing won’t be slower than your normal tests! (Disclimer: while this tool is useful, classic performance testing is still recommended!)

Setup

• install it via pip install django-performance-testing

• add it to your settings and it auto-registers itself

  settings.INSTALLED_APPS = [
     ...
     'django_performance_testing',
     ...
  ]

• set your limits (see below for detail)

• and run your test manage.py test <your app>

For any limit violations, there will be a test failure, and at the end, a Worst Items Report will be printed.

Supported Limits

Querycount

Sets the limit in the number of queries executed inside the given scope. Limits can be set for the total number of queries, or more specifically, based on types of queries - read (SELECT), write ( INSERT, UPDATE, DELETE), and other (e.g.: transaction (savepoints)).

When no (or None) value is provided for a given limit type, that is ignored during the check, as if there were no limit rules for. Thus it’s possible to only focus on no write queries, while ignoring all the other queries that might be executed.

Setting Limits

Predefined limit points

Following are the keys that are currently supported for settings.PERFORMANCE_LIMITS dictionary

• django.test.client.Client - every call to its request method is limited, i.e.: GET, POST, etc.

• Template.render - every render call is checked for limits. Note: it’s recursive, i.e.: include and similar tags result in a check

• test method - the actual various unittest test methods that you write for your app

And the following types of limits are supported:

• queries - contains the values for query count limits, such as read, write, other, total

• time - can specify a limit for the total elapses seconds for the given limit point

Sample Settings

PERFORMANCE_LIMITS = {
    'test method': {
        'queries': {'total': 50},  # want to keep the tests focused
        'time': {'total': 0.2},  # want fast integrated tests, so aiming for 1/5 seconds
    },
    'django.test.client.Client': {
        'queries': {
            'read': 30,
            'write': 8,  # do not create complex object structures in the web
                         # process
        },
    },
    'Template.render': {
        'queries': {
            'write': 0,  # rendering a template should never write to the database!
            'read': 0
        }
    }
}

Ad-Hoc Limits

While the builtin measurement points are great, sometimes, when profiling and trying to improve sections of the code, more granular limits are needed. To support that, the limits can be used as context managers, e.g.:

from django_performance_testing.queries import QueryBatchLimit
from django_performance_testing.timing import TimeLimit
...

def my_method_with_too_many_queries(request):
    with QueryBatchLimit(write=0, read=10):  # initialize form
        form = MyForm(request.POST)
    with QueryBatchLimit(write=0, read=3):  # validate it
        is_valid = form.is_valid()
    if is_valid:
        with QueryBatchLimit(read=0, write=8):  # save it
            form.save()
        with QueryBatchLimit(read=0, write=0):  # redirect
            return HttpResponseRedirect(...)
    else:
        with QueryBatchLimit(write=0):  # render form
            with TimeLimit(total=0.01):   # we need superfast templates
                return form_invalid(form)

Release Notes

• 0.2.0

  • add timing measurement that can be limited

  • remove uniqueness check for collector.id_, as the problems it caused for testing outweighed its benefit for developer debugging aid

  • backwards incompatible:

    • change how settings based limits are specified

    • change the worst report data output/data structure

• 0.1.1 - bugfix release

  • bugfix: attributes set by on test methods (e.g.: @unittest.skip) are now recognizable again and not lost due to the library’s patching

• 0.1.0 - initial release

  • supports Django 1.8, 1.9, 1.10 on python 2.7, 3.3, 3.4, and 3.5

  • query counts are reported and can be limited, by categories - read, write, other, and total

  • support ad-hoc limits by using it as a context manager

  • predefined limits support:

    • django.test.client.Client - all calls to its request method

    • actual unittest test_<foo> methods

    • Template.render

Contributing

As an open source project, we welcome contributions.

The code lives on github.

Reporting issues/improvements

Please open an issue on github or provide a pull request whether for code or for the documentation.

For non-trivial changes, we kindly ask you to open an issue, as it might be rejected. However, if the diff of a pull request better illustrates the point, feel free to make it a pull request anyway.

Pull Requests

• for code changes

  • it must have tests covering the change. You might be asked to cover missing scenarios

  • the latest flake8 will be run and shouldn’t produce any warning

  • if the change is significant enough, documentation has to be provided

Setting up all Python versions

sudo apt-get -y install software-properties-common
sudo add-apt-repository ppa:fkrull/deadsnakes
sudo apt-get update
for version in 3.3 3.5; do
  py=python$version
  sudo apt-get -y install ${py} ${py}-dev
done

Code of Conduct

As it is a Django extension, it follows Django’s own Code of Conduct. As there is no mailing list yet, please just email one of the main authors (see setup.py file or github contributors)