django-query-limiter 0.2.0

Ever wanted to limit how many db queries a certain function or view can make? You're in luck!

Get it from PyPi:

pip install django-query-limiter[formatting]

Basic usage

from your_django_models import Model
from query_limiter import limit_queries

with limit_queries(1):
    print(Model.objects.first()) # Prints your model's first object

with limit_queries(1):
    print(Model.objects.first()) # Prints your model's first object
    print(Model.objects.first()) # Raises QueryLimitError

It can also be used as a function decorator, and can limit queries on a per-database level:

from your_django_models import Model
from query_limiter import limit_queries

@limit_queries(10, db_connections=['default'])
def my_view(request):
    return Model.objects.first()

Multiple limits can be specified, and the first one to be reached will raise a QueryLimitExceeded exception:

from your_django_models import Model
from query_limiter import limit_queries
from datetime import timedelta

@limit_queries(
    amount=2, 
    individual_max_time=timedelta(milliseconds=100), 
    total_max_time=timedelta(seconds=1),
)
def my_view(request):
    Model.objects.first() # if this query takes more than 100ms -> QueryLimitExceeded
    Model.objects.first() # if the total time of all queries takes more than 1s -> QueryLimitExceeded
    Model.objects.first() # if this query is reached -> QueryLimitExceeded

You can globally disable the query limiter:

from your_django_models import Model
from query_limiter import limit_queries, disable_query_limiter

if settings.ENVIROMENT == 'production':
    disable_query_limiter()

with limit_queries(1):
    print(Model.objects.first())  # Prints your model's first object
    print(Model.objects.first())  # Prints your model's first object

The default behaviour is to limit the connections to all databases. This can be globally overwriten like so:

from query_limiter import set_default_databases

set_default_databases(['your_database_name', 'another_database_name'])

Unless the db connections are specified in the limit_queries decorator, these databases will be used.

Formatting

The formatting extra:

• humanizes all timedelta outputs
• uses sqlparse to format the queries to be more human readable