import random
import socket
__author__ = "Artur Barseghyan <artur.barseghyan@gmail.com>"
__copyright__ = "2022-2023 Artur Barseghyan"
__license__ = "MIT"
__all__ = (
"AutoIncPortInt",
"AutoFreePortInt",
)
[docs]class AutoIncPortInt(int):
"""Automatically incremented integer value.
Contains state of issued values. Starts from 2223. Every time
initialized, value increases.
Usage example:
port = AutoInt() # 2223
port = AutoInt() # 2224
port = AutoInt() # 2225
For the rest, it behaves like a normal integer.
For better integration, it's recommended to cast the value to `int`,
like this:
port = int(AutoInt())
"""
# This is a class attribute that keeps the current state
_next_value: int = 2223
def __new__(cls, *args, **kwargs) -> "AutoIncPortInt":
"""Create a new instance of AutoInt with the next value."""
# Use __new__ because int is immutable, so we need to set the value
# before creating the instance.
instance = super().__new__(cls, cls._next_value)
# Increment the class attribute for the next instance
cls._next_value += 1
# Return the new instance
return instance
[docs]class AutoFreePortInt(int):
"""Automatically and randomly picks a free port within a specified range.
For instance:
# Random free port between default range 2223 and 5000
port = AutoFreePortInt()
# Random free port between 3000 and 4000
port = AutoFreePortInt(min_port=3000, max_port=4000)
For the rest, it behaves like a normal integer.
For better integration, it's recommended to cast the value to `int`,
like this:
port = int(AutoFreePortInt())
"""
# Default port range
DEFAULT_MIN_PORT: int = 2223
DEFAULT_MAX_PORT: int = 5000
@staticmethod
def _is_port_free(host: str, port: int) -> bool:
"""Check if the given port is free."""
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
try:
# Try to bind the socket to the port
s.bind((host, port))
return True
except OSError:
return False
def __new__(
cls,
min_port: int = DEFAULT_MIN_PORT,
max_port: int = DEFAULT_MAX_PORT,
host: str = "localhost",
*args,
**kwargs,
) -> "AutoFreePortInt":
"""Create a new instance of `AutoFreePortInt`.
With a free random port within the specified range.
"""
# Validate the range
if not (
isinstance(min_port, int)
and isinstance(max_port, int)
and min_port <= max_port
):
raise ValueError("Invalid port range specified")
# Pick a random port within the specified range and check if it's free
while True:
port = random.randint(min_port, max_port)
if cls._is_port_free(host, port):
break
# Use __new__ to create the instance with the free port as the value
instance = super().__new__(cls, port)
return instance