UseWindowsService does not work with WebApplicationBuilder

[OronDF343]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

In ASP.NET Core 6, it is not possible to call UseWindowsService() when using WebApplicationBuilder. Doing so results in an exception.
This affects any new projects created using the default template for ASP.NET Core 6.

Expected Behavior

The default template for ASP.NET Core 6 should be possible to host in a Windows Service.

Steps To Reproduce

Minimal repro with template:

1. dotnet new webapi -n winsvctest
2. dotnet add package Microsoft.Extensions.Hosting.WindowsServices
3. Edit Program.cs, add this at line 2: builder.Host.UseWindowsService();
4. dotnet publish -c Release
5. sc create winsvctest start=auto DisplayName="winsvctest" binPath="...\winsvctest.exe" (enter the absolute path)
6. sc start winsvctest
7. Check the Event Viewer to see the exception

ASP.NET Core 6 Program.cs (not working):

var builder = WebApplication.CreateBuilder(args);
builder.Host.UseWindowsService();

// Add services to the container.

builder.Services.AddControllers();
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseHttpsRedirection();

app.UseAuthorization();

app.MapControllers();

app.Run();

ASP.NET Core 3.1 Program.cs (working):

using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;

namespace MyService
{
    public class Program
    {
        public static void Main(string[] args)
        {
            CreateHostBuilder(args).Build().Run();
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .UseSerilog()
                .UseWindowsService()
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                });
    }
}

Exceptions (if any)

System.NotSupportedException: The content root changed from "C:\Windows\system32\" to "D:\MyService\". Changing the host configuration using WebApplicationBuilder.Host is not supported. Use WebApplication.CreateBuilder(WebApplicationOptions) instead.
   at Microsoft.AspNetCore.Builder.ConfigureHostBuilder.ConfigureHostConfiguration(Action`1 configureDelegate)
   at Microsoft.Extensions.Hosting.HostingHostBuilderExtensions.UseContentRoot(IHostBuilder hostBuilder, String contentRoot)
   at Microsoft.Extensions.Hosting.WindowsServiceLifetimeHostBuilderExtensions.UseWindowsService(IHostBuilder hostBuilder, Action`1 configure)
   at Microsoft.Extensions.Hosting.WindowsServiceLifetimeHostBuilderExtensions.UseWindowsService(IHostBuilder hostBuilder)
   at Program.<Main>$(String[] args) in C:\Dev\Test\Program.cs:line 2

.NET Version

6.0.200

Anything else?

Possible workaround (from here):

var webApplicationOptions = new WebApplicationOptions() { ContentRootPath = AppContext.BaseDirectory, Args = args, ApplicationName = System.Diagnostics.Process.GetCurrentProcess().ProcessName };
var builder = WebApplication.CreateBuilder(webApplicationOptions);

builder.Host.UseWindowsService();

This workaround was enough for me but has not been extensively tested.

The documentation does not address the newer APIs: https://docs.microsoft.com/en-us/aspnet/core/host-and-deploy/windows-service?view=aspnetcore-6.0&tabs=visual-studio

[Tratcher]

Related: dotnet/aspnetcore#37464

[adityamandaleeka]

Triage: we could improve the message here to be more detailed about what specific option you'd need to set.

[ghost]

Tagging subscribers to this area: @dotnet/area-extensions-hosting
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

In ASP.NET Core 6, it is not possible to call UseWindowsService() when using WebApplicationBuilder. Doing so results in an exception.
This affects any new projects created using the default template for ASP.NET Core 6.

Expected Behavior

The default template for ASP.NET Core 6 should be possible to host in a Windows Service.

Steps To Reproduce

Minimal repro with template:

1. dotnet new webapi -n winsvctest
2. dotnet add package Microsoft.Extensions.Hosting.WindowsServices
3. Edit Program.cs, add this at line 2: builder.Host.UseWindowsService();
4. dotnet publish -c Release
5. sc create winsvctest start=auto DisplayName="winsvctest" binPath="...\winsvctest.exe" (enter the absolute path)
6. sc start winsvctest
7. Check the Event Viewer to see the exception

ASP.NET Core 6 Program.cs (not working):

var builder = WebApplication.CreateBuilder(args);
builder.Host.UseWindowsService();

// Add services to the container.

builder.Services.AddControllers();
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseHttpsRedirection();

app.UseAuthorization();

app.MapControllers();

app.Run();

ASP.NET Core 3.1 Program.cs (working):

using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;

namespace MyService
{
    public class Program
    {
        public static void Main(string[] args)
        {
            CreateHostBuilder(args).Build().Run();
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .UseSerilog()
                .UseWindowsService()
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                });
    }
}

Exceptions (if any)

System.NotSupportedException: The content root changed from "C:\Windows\system32\" to "D:\MyService\". Changing the host configuration using WebApplicationBuilder.Host is not supported. Use WebApplication.CreateBuilder(WebApplicationOptions) instead.
   at Microsoft.AspNetCore.Builder.ConfigureHostBuilder.ConfigureHostConfiguration(Action`1 configureDelegate)
   at Microsoft.Extensions.Hosting.HostingHostBuilderExtensions.UseContentRoot(IHostBuilder hostBuilder, String contentRoot)
   at Microsoft.Extensions.Hosting.WindowsServiceLifetimeHostBuilderExtensions.UseWindowsService(IHostBuilder hostBuilder, Action`1 configure)
   at Microsoft.Extensions.Hosting.WindowsServiceLifetimeHostBuilderExtensions.UseWindowsService(IHostBuilder hostBuilder)
   at Program.<Main>$(String[] args) in C:\Dev\Test\Program.cs:line 2

.NET Version

6.0.200

Anything else?

Possible workaround (from here):

var webApplicationOptions = new WebApplicationOptions() { ContentRootPath = AppContext.BaseDirectory, Args = args, ApplicationName = System.Diagnostics.Process.GetCurrentProcess().ProcessName };
var builder = WebApplication.CreateBuilder(webApplicationOptions);

builder.Host.UseWindowsService();

This workaround was enough for me but has not been extensively tested.

The documentation does not address the newer APIs: https://docs.microsoft.com/en-us/aspnet/core/host-and-deploy/windows-service?view=aspnetcore-6.0&tabs=visual-studio

Author:	OronDF343
Assignees:	halter73
Labels:	area-Extensions-Hosting
Milestone:	-