pw_hdlc/rpc_example/example_script.py

#!/usr/bin/env python
# Copyright 2020 The Pigweed Authors
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may not
# use this file except in compliance with the License. You may obtain a copy of
# the License at
#
#     https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations under
# the License.
"""Simple example script that uses pw_rpc."""

import argparse
import os
from pathlib import Path

import serial  # type: ignore

from pw_hdlc.rpc import HdlcRpcClient, default_channels

# Point the script to the .proto file with our RPC services.
PROTO = Path(os.environ['PW_ROOT'], 'pw_rpc/echo.proto')


def script(device: str, baud: int) -> None:
    # Set up a pw_rpc client that uses HDLC.
    ser = serial.Serial(device, baud, timeout=0.01)
    client = HdlcRpcClient(lambda: ser.read(4096), [PROTO],
                           default_channels(ser.write))

    # Make a shortcut to the EchoService.
    echo_service = client.rpcs().pw.rpc.EchoService

    # Call some RPCs and check the results.
    status, payload = echo_service.Echo(msg='Hello')

    if status.ok():
        print('The status was', status)
        print('The payload was', payload)
    else:
        print('Uh oh, this RPC returned', status)

    status, payload = echo_service.Echo(msg='Goodbye!')

    print('The device says:', payload.msg)


def main():
    parser = argparse.ArgumentParser(
        description=__doc__,
        formatter_class=argparse.ArgumentDefaultsHelpFormatter)
    parser.add_argument('--device',
                        '-d',
                        default='/dev/ttyACM0',
                        help='serial device to use')
    parser.add_argument('--baud',
                        '-b',
                        type=int,
                        default=115200,
                        help='baud rate for the serial device')
    script(**vars(parser.parse_args()))


if __name__ == '__main__':
    main()