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https://github.com/Mityuha/fresh-bakery

Bake dependency injections asynchronously and stupidly simple
https://github.com/Mityuha/fresh-bakery

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Bake dependency injections asynchronously and stupidly simple

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README 

        




  fresh-bakery





    🍰 The little DI framework that tastes like a cake. 🍰




---



**Documentation**: [https://fresh-bakery.readthedocs.io/en/latest/](https://fresh-bakery.readthedocs.io/en/latest/)



---



# Fresh Bakery



Fresh bakery is a lightweight [Dependency Injection][DI] framework/toolkit,

which is ideal for building object dependencies in Python.



It is [fully] production-ready, and gives you the following:



* A lightweight, stupidly simple DI framework.

* Fully asynchronous, no synchronous mode.

* Any async backends compatible (`asyncio`, `trio`).

* Zero dependencies.

* `Mypy` compatible (no probably need for `# type: ignore`).

* `FastAPI` fully compatible.

* `Litestar` compatible.

* `Pytest` fully compatible (Fresh Bakery encourages the use of `pytest`).

* Ease of testing.

* Easily extended (contribution is welcome).



## Requirements



Python 3.8+



## Installation



```shell

$ pip3 install fresh-bakery

```



## Examples



### Quickstart

This example is intended to show the nature of Dependency Injection and the ease of use the library. Many of us work 8 hours per day on average, 5 days a week, i.e. ~ 40 hours per week. Let's describe it using DI and bakery:

```python

from bakery import Bakery, Cake



def full_days_in(hours: int) -> float:

    return hours / 24



def average(total: int, num: int) -> float:

    return total / num



class WorkingBakery(Bakery):

    average_hours: int = Cake(8)

    week_hours: int = Cake(sum, [average_hours, average_hours, 7, 9, average_hours])

    full_days: float = Cake(full_days_in, week_hours)



async def main() -> None:

    async with WorkingBakery() as bakery:

        assert bakery.week_hours == 40

        assert bakery.full_days - 0.00001 < full_days_in(40)

        assert int(bakery.average_hours) == 8

```

You can see it's as simple as it can be.



### One more example

Let's suppose we have a thin wrapper around file object.

```python

from typing import ClassVar, Final



from typing_extensions import Self



class FileWrapper:

    file_opened: bool = False

    write_lines: ClassVar[list[str]] = []



    def __init__(self, filename: str) -> None:

        self.filename: Final = filename



    def write(self, line: str) -> int:

        type(self).write_lines.append(line)

        return len(line)



    def __enter__(self) -> Self:

        type(self).file_opened = True

        return self



    def __exit__(self, *_args: object) -> None:

        type(self).file_opened = False

        type(self).write_lines.clear()

```

This wrapper acts exactly like a file object: it can be opened, closed, and can write line to file.

Let's open file `hello.txt`, write 2 lines into it and close it. Let's do all this with the bakery syntax:

```python

from bakery import Bakery, Cake



class FileBakery(Bakery):

    _file_obj: FileWrapper = Cake(FileWrapper, "hello.txt")

    file_obj: FileWrapper = Cake(_file_obj)

    write_1_bytes: int = Cake(file_obj.write, "hello, ")

    write_2_bytes: int = Cake(file_obj.write, "world")



async def main() -> None:

    assert FileWrapper.file_opened is False

    assert FileWrapper.write_lines == []

    async with FileBakery() as bakery:

        assert bakery.file_obj.filename == "hello.txt"

        assert FileWrapper.file_opened is True

        assert FileWrapper.write_lines == ["hello, ", "world"]



    assert FileWrapper.file_opened is False

    assert FileWrapper.write_lines == []

```

Maybe you noticed some strange things concerning `FileBakery` bakery:

1. `_file_obj` and `file_obj` objects. Do we need them both?

2. Unused `write_1_bytes` and `write_2_bytes` objects. Do we need them?



Let's try to fix both cases. First, let's figure out why do we need `_file_obj` and `file_obj` objects?

- The first `Cake` for `_file_obj` initiates `FileWrapper` object, i.e. calls `__init__` method;

- the second `Cake` for `file_obj` calls context-manager, i.e. calls `__enter__` method on enter and `__exit__` method on exit.



Actually, we can merge these two statements into single one:

```python

# class FileBakery(Bakery):

    file_obj: FileWrapper = Cake(Cake(FileWrapper, "hello.txt"))

```

So, what about unused arguments? OK, let's re-write this gist a little bit. First, let's declare the list of strings we want to write:

```python

# class FileBakery(Bakery):

    strs_to_write: list[str] = Cake(["hello, ", "world"])

```

How to apply function to every string in this list? There are several ways to do it. One of them is built-in [`map`](https://docs.python.org/3/library/functions.html#map) function.

```python

map_cake = Cake(map, file_obj.write, strs_to_write)

```

But `map` function returns iterator and we need to get elements from it. Built-in [`list`](https://docs.python.org/3/library/functions.html#func-list) function will do the job.

```python

list_cake = Cake(list, map_cake)

```

In the same manner as we did for `file_obj` let's merge these two statements into one. The final `FileBakery` will look like this:

```python

class FileBakeryMap(Bakery):

    file_obj: FileWrapper = Cake(Cake(FileWrapper, "hello.txt"))

    strs_to_write: list[str] = Cake(["hello, ", "world"])

    _: list[int] = Cake(list, Cake(map, file_obj.write, strs_to_write))

```

The last thing nobody likes is hard-coded strings! In this case such strings are:

- the name of the file `hello.txt`

- list of strings to write: `hello, ` and `world`



What if we've got another filename or other strings to write? Let's define filename and list of strings as `FileBakery` parameters:

```python

from bakery import Bakery, Cake, __Cake__



class FileBakery(Bakery):

    filename: str = __Cake__()

    strs_to_write: list[str] = __Cake__()

    file_obj: FileWrapper = Cake(Cake(FileWrapper, filename))

    _: list[int] = Cake(list, Cake(map, file_obj.write, strs_to_write))

```

To define parameters you can use dunder-cake construction: `__Cake__()`.   

To pass arguments into `FileBakery` you can use native python syntax:

```python

# async def main() -> None:

    async with FileBakeryMapWithParams(

        filename="hello.txt", strs_to_write=["hello, ", "world"]

    ) as bakery:

        ...

```

And the whole example will look like this:

```python

from typing import ClassVar, Final



from typing_extensions import Self



from bakery import Bakery, Cake, __Cake__



# class FileWrapper: ...



class FileBakery(Bakery):

    filename: str = __Cake__()

    strs_to_write: list[str] = __Cake__()

    file_obj: FileWrapper = Cake(Cake(FileWrapper, filename))

    _: list[int] = Cake(list, Cake(map, file_obj.write, strs_to_write))



async def main() -> None:

    assert FileWrapper.file_opened is False

    assert FileWrapper.write_lines == []

    async with FileBakeryMapWithParams(

        filename="hello.txt", strs_to_write=["hello, ", "world"]

    ) as bakery:

        assert bakery.file_obj.filename == "hello.txt"

        assert FileWrapper.file_opened is True

        assert FileWrapper.write_lines == ["hello, ", "world"]



    assert FileWrapper.file_opened is False

    assert FileWrapper.write_lines == []

```

More examples are presented in section [bakery examples](https://fresh-bakery.readthedocs.io/en/latest/bakery_examples/).



## Dependencies



No dependencies ;)



## Changelog

You can see the release history here: https://github.com/Mityuha/fresh-bakery/releases/



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Fresh Bakery is MIT licensed code.