iterable-subprocess 0.0.1

Communicate with a subprocess using iterables: for when data is too big to fit in memory and has to be streamed

iterable-subprocess

Python utility function to communicate with a subprocess using iterables: for when data is too big to fit in memory and has to be streamed.

Data is sent to a subprocess's standard input via an iterable, and extracted via another iterable. This allows an external subprocess to be naturally placed in a chain of iterables for streaming processing.

Installation

pip install iterable-subprocess

Usage

A single function iterable_subprocess is exposed. The first parameter is the args argument passed to the Popen Constructor, and the second is an iterable whose items must be bytes instances and are sent to the subprocess's standard input.

Returned from the function is an iterable whose items are bytes instances of the processes standard output.

from iterable_subprocess import iterable_subprocess

def yield_input():
    # In a real case could read from the filesystem or the network
    yield b'first\n'
    yield b'second\n'
    yield b'third\n'

output = iterable_subprocess(['cat'], yield_input())

for chunk in output:
    print(chunk)