redis_models 0.4.0

This package provides a simple model structure for redis based storage.

Redis Models

This package provides a simple model structure for redis based storage. It acts like an ORM and allows you to create models with validation.

Installation

pip install redis_models

Usage

First, you need to create your model. It's similar to Pydantic models, or built-in dataclass.

from redis_models.models import RedisModel


class MyUserModel(RedisModel):
    name: str
    age: int

    class Meta:
        redis_url = "redis://localhost:6379/0"
        indexes = ("name", )

Let's create a User object

user = User(name="John Doe", age=30)

Let's try creating an object that does not fit to the definition

try:
    bad_user = User(name="John", eye_color="blue")
except ValidationError:
    pass

Let's write it to Redis

user.save()

Let's see its id. ids are UUID4 hex strings

print(user.id)

Fetch the record from Redis

user_again = User.get(id=user.id)

See the object as dictionary

print(user.asd)

Let's delete the record

user_again.delete()

Trying to find a non-existing record throws NotFound exception

from redis_models.errors import NotFound

try:
    user_not_found = User.get(id=user_again.id)
except NotFound:
    print("User not found!")

Trying to filter with exact values. In this example, name field is noted as an index in the model.

User.filter(name="nejdet")  # Returns a list of dictionaries

How it works

This package relies on RedisModelMeta and RedisModel classes. RedisModelMeta is a type constructor and RedisModel is a class that contains required methods for derived models.

When you call YourModel.save() the method will

• Run YourModel.asdict() and get the whole data serialized to JSON (Therefore each field must be JSON-serializable!)

• Create a key like YourModel-data-<SOME_UUID> and puts the whole serialized data as value

• Create an index set for each field you put in YourModel.Meta.indexes using YourModel-index-<INDEX_FIELD_NAME>-<INDEX_FIELD_VALUE> format and UUID for each record as a value.

When you call YourModel.get(id=id_value) the method will search among YourModel-data-<SOME_UUID> keys and return the data.

When you call YourModel.filter(index1=value1, index2=value2) the method will

• Use SINTER to have an intersection for UUIDs.
• Then uses MGET to get multiple values at once.
• Returns a generator that yields YourModel objects (for memory efficiency).