ipydrawio/atest/ports.py

"""get a random port"""

# Copyright 2021 ipydrawio contributors
#
# 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
#
#     http://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.

import socket


def get_unused_port():
    """Get an unused port by trying to listen to any random port.

    Probably could introduce race conditions if inside a tight loop.
    """
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.bind(("localhost", 0))
    sock.listen(1)
    port = sock.getsockname()[1]
    sock.close()
    return port