Files
pycapnp/examples/async_client.py
Jacob Alexander 6e7fffd7de Applying black formatting
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2021-10-01 11:12:21 -07:00

90 lines
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Python
Executable File

#!/usr/bin/env python3
import asyncio
import argparse
import time
import capnp
import socket
import thread_capnp
capnp.remove_event_loop()
capnp.create_event_loop(threaded=True)
def parse_args():
parser = argparse.ArgumentParser(
usage="Connects to the Example thread server \
at the given address and does some RPCs"
)
parser.add_argument("host", help="HOST:PORT")
return parser.parse_args()
class StatusSubscriber(thread_capnp.Example.StatusSubscriber.Server):
"""An implementation of the StatusSubscriber interface"""
def status(self, value, **kwargs):
print("status: {}".format(time.time()))
async def myreader(client, reader):
while True:
data = await reader.read(4096)
client.write(data)
async def mywriter(client, writer):
while True:
data = await client.read(4096)
writer.write(data.tobytes())
async def background(cap):
subscriber = StatusSubscriber()
promise = cap.subscribeStatus(subscriber)
await promise.a_wait()
async def main(host):
host = host.split(":")
addr = host[0]
port = host[1]
# Handle both IPv4 and IPv6 cases
try:
print("Try IPv4")
reader, writer = await asyncio.open_connection(
addr, port, family=socket.AF_INET
)
except Exception:
print("Try IPv6")
reader, writer = await asyncio.open_connection(
addr, port, family=socket.AF_INET6
)
# Start TwoPartyClient using TwoWayPipe (takes no arguments in this mode)
client = capnp.TwoPartyClient()
cap = client.bootstrap().cast_as(thread_capnp.Example)
# Assemble reader and writer tasks, run in the background
coroutines = [myreader(client, reader), mywriter(client, writer)]
asyncio.gather(*coroutines, return_exceptions=True)
# Start background task for subscriber
tasks = [background(cap)]
asyncio.gather(*tasks, return_exceptions=True)
# Run blocking tasks
print("main: {}".format(time.time()))
await cap.longRunning().a_wait()
print("main: {}".format(time.time()))
await cap.longRunning().a_wait()
print("main: {}".format(time.time()))
await cap.longRunning().a_wait()
print("main: {}".format(time.time()))
if __name__ == "__main__":
asyncio.run(main(parse_args().host))