Rich C Rich C - 3 months ago 15
C# Question

Grapevine 3.1 - 'The process cannot access the file'

I have a solution that utilises Grapevine to start a server within the

Program
class.
For some reason though, as soon as I start the program, it crashes when
server.Start()
is called.
No other parts of the solution are running at this point, so I don't know how that could be happening?

Running in Visual Studio 15, as Administrator, on Windows 10.

Program.cs


using System;
using System.Threading;
using Grapevine.Server;
using QuantConnect.Logging;

namespace QuantConnect.Services
{
class Program
{
/// <summary>
/// QuantConnect C# Services Server:
/// </summary>
static void Main(string[] args)
{
var server = new RESTServer
{
//Host = Configuration.Config.Get("grapevine-host"),
//Port = Configuration.Config.Get("grapevine-port")
Host = Configuration.Config.Get("grapevine-host", "localhost"),
Port = Configuration.Config.Get("grapevine-port", "80")
};

Log.Trace(string.Format("Starting Server On {0}:{1}", server.Host, server.Port));
server.Start(); // Exception occurs here

while (server.IsListening)
{
Thread.Sleep(300);
}

Log.Trace("Server stopped. Press key to continue...");
Console.ReadLine();
}
}
}


Error and stacktrace:

An unhandled exception of type 'System.Net.HttpListenerException' occurred in Grapevine.dll


System.Net.HttpListenerException was unhandled
ErrorCode=32
HResult=-2147467259
Message=The process cannot access the file because it is being used by another process
NativeErrorCode=32
Source=System
StackTrace:
at System.Net.HttpListener.AddAllPrefixes()
at System.Net.HttpListener.Start()
at Grapevine.Server.RESTServer.Start()
at QuantConnect.Services.Program.Main(String[] args) in C:\Users\RichardsPC\Source\Repos\Lean\Services\Program.cs:line 29
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
InnerException:

Answer

So I figured out what the issue was. I set Grapevine to use port 80.

Port = Configuration.Config.Get("grapevine-port", "80")

Issue was that there was another service on my machine using this port, I changed it to use 8080 and it works fine now.

Port = Configuration.Config.Get("grapevine-port", "8080")