django-cacheable-model 1.0.2

A cacheable Django model

django cacheable model

A cacheable model for django.

• A generic way of creating cache keys from Django model fields
• Retrieve django models from cache with field values (cache on the way if cache missed)
• Retrieve all the model instances (suitable for small set of models)

See usage example below

1. Github

https://github.com/harisankar-krishna-swamy/django_cacheable_model

2. Install

pip install django_cacheable_model

3. Configuration

• CACHE_SET_MANY_LIMIT is chunk size for calls to cache.set_many.
  when all_ins_from_cache brings in all entries from cache, it will set each object
  in chunks to control request size. Default is 5 i.e if there are 10 instances of a model
  from db this config will set each of the models to the cache in two groups of 5

4. Usage

See samples in example_django_project views.py and models.py.

4.1. Create a model that inherits from CacheableModel

class Question(CacheableModel):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField('date published')


class Choice(CacheableModel):
    question = models.ForeignKey(Question, on_delete=models.CASCADE)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)

4.2. Use cache operations from django_cacheable_model.utils

from django_cacheable_model.utils import all_ins_from_cache, model_ins_from_cache

# Get all instances of model from cache (use for smaller set of models)
context['choices'] = all_ins_from_cache(Choice)

# Get all instances with select_related and order_by
choices = all_ins_from_cache(Choice,
                             select_related=('question',),
                             order_by_fields=('-id',))

# Get a single model. Note this method returns a list of matching objects
context['choice'] = model_ins_from_cache(Choice, {'id': 5})[-1]

5. To do

a) Example and document use of prefetch_related
b) Doc and tests for util methods
c) timeout in documentation

6. License

Apache2 License

7. Development

7.1 Python

Python 3.10.10 is used for development. Pyenv is used for managing Python versions.
Install dev requirements in dev-requirements.txt

# in root folder
# Set python version for project folder using pyenv
pyenv local 3.10.10
# Create virtual environment 
python3 -m venv .venv
# Activate the virtual environment
source .venv/bin/activate
# Install all packages
pip install -r dev-requirements.txt
pre-commit install

7.2 IDE (PyCharm) setup

Set Python interpreter to the virtual env created
Set .venv folder as excluded in Pycharm
Set src folder as source root
For test runs from IDE set src as working directory

7.3 Test

1. Start memcached container for caching

cd src/tests/containers
# pull container and 
docker-compose pull
docker-compose up -d
# Check container is running
docker ps

2. Run tests

cd src
pytest