PortFinder

PortFinder.cs

using System;
using System.Collections.Generic;
using System.Net;
using System.Net.Sockets;

namespace Ylp.ExampleTests.Fixtures;

public static class PortFinder
{
    static readonly List<int> UsedPorts = new();
    static readonly object SyncRoot = new();
        
    public static int Next(int minValue = 9000, int maxValue = 15000)
    {
        lock (SyncRoot)
        {
            for (var port = minValue; port <= maxValue; port++)
            {
                if (UsedPorts.Contains(port) || !IsPortAvailable(port))
                    continue;
                
                UsedPorts.Add(port);

                return port;
            }
        }
        
        throw new Exception($"No available ports in range {minValue} - {maxValue}");
    }
    
    static bool IsPortAvailable(int port)
    {
        try
        {
            using var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            socket.Bind(new IPEndPoint(IPAddress.Loopback, port));
            return true;
        }
        catch
        {
            return false;
        }
    }
}