GRPC Python Request and Response Streaming

SyncStream.py

import threading
from time import sleep


DEFAULT_SLEEP_TIME = 0.00001


class SyncStream:

  def __init__(self, sleep_time = DEFAULT_SLEEP_TIME):
    self._semaphore = threading.Semaphore()
    self._data = None
    self._closed = False
    self._sleep_time = sleep_time

  def close(self):
    self._closed = True
    try:
      self._semaphore.release()
    except:
      pass

  def send(self, data):
    self._semaphore.acquire()
    self._data = data
    self._semaphore.release()

  def stream(self):
    while not self._closed:
      self._semaphore.acquire()
      data = self._data
      self._data = None
      self._semaphore.release()
      if self._closed:
        break
      if not data is None:
        yield data
      # make sure that we don't busy wait too much
      sleep(self._sleep_time)

# vim: expandtab:ts=2:sw=2:

This will give you the ability to implement

• unary stream
• stream stream
• stream unary

based clients and services using Python.