sync_main.py

"""
Run this example with:
 python -m github.sync_main

This is an example of using Effect in a normal program that uses
synchronous/blocking functions to do I/O.

This code has these responsibilities:

- set up a dispatcher that knows how to find performers for all intents
 used in this application. The application uses ReadLine, HTTPRequest, and
 ParallelEffects.
- use :func:`effect.sync_perform` to perform an effect, which returns the
 result of the effect (or raises an exception it it failed).
"""

from __future__ import print_function

from functools import partial
from multiprocessing.pool import ThreadPool

from effect import ComposedDispatcher, ParallelEffects, TypeDispatcher, sync_perform
from effect.threads import perform_parallel_with_pool


from ehttp.http_intent import HTTPRequest
from ehttp.sync_http import perform_request_requests
from readline_intent import ReadLine, perform_readline_stdin

from .core import main_effect


def get_dispatcher():
 """
 Create a dispatcher that can find performers for :obj:`ReadLine`,
 :obj:`HTTPRequest`, and :obj:`ParallelEffects`. There's a built-in
 performer for ParallelEffects that uses a multiprocessing ThreadPool,
 :func:`effect.perform_parallel_with_pool`.
 """
 my_pool = ThreadPool()
 pool_performer = partial(perform_parallel_with_pool, my_pool)
 return ComposedDispatcher(
 [
 TypeDispatcher(
 {
 ReadLine: perform_readline_stdin,
 HTTPRequest: perform_request_requests,
 ParallelEffects: pool_performer,
 }
 )
 ]
 )


def main():
 dispatcher = get_dispatcher()
 eff = main_effect()
 print(sync_perform(dispatcher, eff))


if __name__ == "__main__":
 main()