Binding to Heroku dynamic $PORT and keep getting error?

Question

I keep getting this error from the heroku logs:

Error R10 (Boot timeout) -> Web process failed to bind to $PORT within 60 seconds of launch

I have an ASP.NET Core 2.1 app that I'm trying to deploy to Heroku. This is what I do at startup:

if (!int.TryParse(Environment.GetEnvironmentVariable("PORT"), out var port))
{ port = 5000; }

return WebHost
    .CreateDefaultBuilder(args)
    .UseStartup<Startup>()
    .UseKestrel(options =>
    {
        options.Listen(IPAddress.Loopback, port);
    });

This is my Dockerfile

FROM microsoft/dotnet:2.1-aspnetcore-runtime
WORKDIR /app
COPY . .

ENV ASPNETCORE_ENVIRONMENT=Production

CMD dotnet MyApp.dll

I can see the app is starting OK, I even see it's successfully binding to something like http://127.0.0.1:48684 which means it's getting the $PORT, but at the time of a request I get the above error. I cannot use EXPOSE $PORT because it's given at run time.

I've been wrestling with this for a while now. Any help would be much appreciated.

score 2 · Accepted Answer · answered Feb 10 '20 at 03:46

It happens that after a few minutes posting this question I found this answer which solves my problem. I changed the listen options to options.Listen(IPAddress.Any, port);.

if (!int.TryParse(Environment.GetEnvironmentVariable("PORT"), out var port))
{ port = 5000; }

return WebHost
    .CreateDefaultBuilder(args)
    .UseStartup<Startup>()
    .UseKestrel(options =>
    {
        options.Listen(IPAddress.Any, port);
    });

Binding to Heroku dynamic $PORT and keep getting error?

1 Answers1