kabutobashi 0.8.1

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kabutobashi

Core Concept

@block-decorator and Flow-class is important. @block automatically generates input and output functions, allowing you to focus solely on the processing. Flow allows you to focus solely on the process flow and input parameters.

About @block-decorator

simple decorator is like below.

def simple_decorator(func):
    def wrap_func() -> str:
        res = func()
        return f"Hello, {res}"
    return wrap_func


@simple_decorator
def world() -> str:
    return "world"


world()  # => "Hello, world"

A decorator is something that dynamically generates and adds processes to functions or classes, similar to its name.

First, prepare a function as follows and decorate it with @block.

from kabutobashi import block

@block()
class UdfBlock:
    term: int = 10

    def _process(self):
        return {"doubled_term": self.term * 2}

The classes above is equivalent to the following class definition.

import pandas as pd
from kabutobashi.domain.entity.blocks import BlockGlue

class UdfBlock:
    series: pd.DataFrame = None
    params: dict = None
    term: int = 10
    block_name: str = "udf_block"

    def _process(self):
        return {"doubled_term": self.term * 2}
    
    def process(self):
        return self._process()

    def factory(self, glue: BlockGlue) -> "UdfBlock":
        # Omitted. In reality, processes are described.
        ...

    def _factory(self, glue: BlockGlue) -> "UdfBlock":
        # Omitted. In reality, processes are described.
        ...

    def glue(self, glue: BlockGlue) -> BlockGlue:
        # Omitted. In reality, processes are described.
        ...

In classes decorated with @block, it is not recommended to execute the __init__() method. Instead, it is recommended to use the factory() class-method.

factory() method description. process() method description. glue() method description.

Up to this point, the use of the @block decorator with classes such as UdfClass has described, but using the Block class on its own is not intended. Please read the following explanation of the Flow class for more details.

Read-Block

• input
  • params
• output
  • series

Crawl-Block

• input
  • params
• output
  • output.params

Extract-Block

• input
  • params
• output
  • output.params

PreProcess-Block

• input
  • series
  • params
• output
  • series

Process-Block

• input
  • series
  • params
• output
  • output.series

Parameterize-Block

• input
  • series
  • params
• output
  • output.params

Reduce-Block

• input
  • series
  • params
• output
  • params

About Flow-class

Blocks are meant to be combined.

Processes always consist of combinations of multiple simple operations. And the only tedious part is aligning their inputs and outputs.

Therefore, in Flow-class, it automatically resolves the sequence of those processes for users, as long as you provide the initial values.

usage

import kabutobashi as kb

# n日前までの営業日の日付リストを取得する関数
target_date = "2020-01-01"
date_list = kb.get_past_n_days(target_date, n=40)