Host shuts down immediately

[rachelappel]

Moved from the docs repo to here. Originally filed by @srininz77 at dotnet/AspNetCore.Docs#6862

"I'm trying to run a long running background task in a console application inside docker container.

My code is as follows:

 public static async Task Main(string[] args)
 {
            var hostBuilder = new HostBuilder()
                .ConfigureAppConfiguration
                (
                    (hostBuilderContext, configurationBuilder) =>
                    {
                        configurationBuilder.SetBasePath(Directory.GetCurrentDirectory());
                        configurationBuilder.AddEnvironmentVariables();
                        configurationBuilder.AddJsonFile("appsettings.json", optional: true);
                    }
                )
                .ConfigureServices
                (
                    (hostBuilderContext, services) =>
                    {
                        services.AddHostedService<HostedService>();
                        services.AddSingleton<ISocketImplementation, SocketImplementation>();
                        services.AddSingleton<IMessageHandler, MessageHandler>();
                    }
                );               

            await hostBuilder.RunConsoleAsync();
   }

**When I use Docker run -d to create the container, the container stops immediately. It doesn't look like RunConsoleAsync() is waiting for ctrl+c or SIGTERM.

I tried GenericHostSample and it behaves the same as well**"

[Tratcher]

It should wait for one of these two:
https://github.com/aspnet/Hosting/blob/ec51afd9d0a973c2a00b37a4c4e529b48ce816bf/src/Microsoft.Extensions.Hosting/Internal/ConsoleLifetime.cs#L43-L52
Maybe it's getting some unexpected input through docker? Or maybe it's running into another error and crashing?

[srininz77]

There are no errors. It runs fine when I launch the container from Visual studio because visual studio adds the "tail" process to the container which is keeping the container alive. When I launch it using Docker run the container stops immediately.

[davidfowl]

Yea, it sounds like something is crashing or failing to start. Try running the container interactively and running the process manually inside of it.

[srininz77]

The issue only exists for images built by VisualStudio but not for images built on our build server. Not sure why? Anyway, generic host works as expected. Thanks.

[Eilon]

Closing because it seems the main issues have been resolved. Thanks!