Dynamo Dao

Typed library for interacting with DynamoDb tables.

Installation

Available on PyPI

pip install dynamo-dao

Usage

The following example code shows some basic usage of this package. Note that the ExampleDao must define 4 abstract properties:

1. table_name - Name of the DynamoDb table resource (maps directly to what you'd see on the AWS console).
2. unique_key - The list of keys that together uniquely define an entry in the table.
3. convert_to_dynamo - A method which takes in the object and converts it to the entry in the DynamoDb table
4. convert_from_dynamo - The opposite of convert_to_dynamo

from typing import NamedTuple

from dynamo_dao import Dao, DynamoObject

class Example(NamedTuple):
    foo: str
    bar: int

class ExampleDao(Dao[Example]):
    table_name = "example"
    unique_key = ["foo"]

    def convert_to_dynamo(self, var: Example) -> DynamoObject:
        return {"foo": var.foo, "bar": var.bar}

    def convert_from_dynamo(self, var: DynamoObject) -> Example:
        return Example(foo=str(var["foo"]), bar=int(var["bar"]))


example_dao = ExampleDao()

example = Example(foo="hi", bar=1)

example_dao.create(example)
result = example_dao.read_one("foo", "hi")

assert example == result

Why use?

The base dao is a generic object, which means child classes will benefit from type checking on functions like read and create.

In the example above, the type of result is Example.