After migrating from IWebHostBuilder to IHostBuilder, the ASP.NET Core API is unable to access the 'applicationUrl' configuration from 'launchSettings.json'.

Question

After migrating from IWebHostBuilder to IHostBuilder, the ASP.NET Core API is unable to access the 'applicationUrl' configuration from 'launchSettings.json'.

Subir Das 0

Hello,
I recently transitioned my ASP.NET Core API from utilizing IWebHostBuilder to IHostBuilder as part of an upgrade to align with modern .NET practices. Post-migration, I'm facing a challenge: the API fails to launch correctly in both development environments and within Linux Docker containers for production deployment. This issue arises specifically when the 'config.Sources.Clear()' command is active in the 'ConfigureAppConfiguration' method, which is essential for custom configuration management. I need guidance on how to successfully run the API with 'config.Sources.Clear()' in place, ensuring that it works seamlessly across different environments while adhering to the enhanced configuration patterns introduced by IHostBuilder.

Exception :

Exception error -
Failed to bind to address http://127.0.0.1:5000: address already in use.
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.AddressBinder.<BindEndpointAsync>d__3.MoveNext()
   at Microsoft.AspNetCore.Server.Kestrel.Core.LocalhostListenOptions.<BindAsync>d__2.MoveNext()
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.AddressBinder.DefaultAddressStrategy.<BindAsync>d__0.MoveNext()
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.AddressBinder.<BindAsync>d__0.MoveNext()
   at Microsoft.AspNetCore.Server.Kestrel.Core.KestrelServerImpl.<BindAsync>d__33.MoveNext()
   at Microsoft.AspNetCore.Server.Kestrel.Core.KestrelServerImpl.<StartAsync>d__30`1.MoveNext()
   at Microsoft.AspNetCore.Hosting.GenericWebHostService.<StartAsync>d__37.MoveNext()
   at Microsoft.Extensions.Hosting.Internal.Host.<StartAsync>d__12.MoveNext()
   at Microsoft.Extensions.Hosting.HostingAbstractionsHostExtensions.<RunAsync>d__4.MoveNext()
   at Microsoft.Extensions.Hosting.HostingAbstractionsHostExtensions.<RunAsync>d__4.MoveNext()
   at Microsoft.Extensions.Hosting.HostingAbstractionsHostExtensions.Run(IHost host)
   at AIProducerBackend.Web.Program.Main(String[] args) in C:\Users\SubirDas\source\repos\AIProducerBackend\SubirLocalRepo\AiProducerBackend.Web\Program.cs:line 28

Inner exception  
Only one usage of each socket address (protocol/network address/port) is normally permitted.
   at Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets.SocketConnectionListener.Bind()
   at Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets.SocketTransportFactory.BindAsync(EndPoint endpoint, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure.TransportManager.<BindAsync>d__9.MoveNext()
   at Microsoft.AspNetCore.Server.Kestrel.Core.KestrelServerImpl.<>c__DisplayClass30_0`1.<<StartAsync>g__OnBind|0>d.MoveNext()
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.AddressBinder.<BindEndpointAsync>d__3.MoveNext()

Reupdate:

public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
    WebHost.CreateDefaultBuilder(args)
    .ConfigureAppConfiguration((webHostBuilderContext, configurationBuilder) =>
    {
        var env = webHostBuilderContext.HostingEnvironment;
        DotNetEnv.Env.LoadMulti(new[] {
            $".env",
            $".env.{env.EnvironmentName}"
        });
        // Clear default IHostBuilder config providers
        configurationBuilder.Sources.Clear();
        configurationBuilder
            .AddJsonFile($"appsettings.json", optional: false)
            .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
            .AddEnvironmentVariables("APP_");
    })
    .UseStartup<Startup>();

Post update:

public static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args)
    .ConfigureAppConfiguration((hostingContext, config) =>
    {
        var env = hostingContext.HostingEnvironment;
        config.Sources.Clear();
        DotNetEnv.Env.LoadMulti(new[] {
            $".env",
            $".env.{env.EnvironmentName}"
        });
        config
            .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
            .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true, reloadOnChange: true)
            .AddEnvironmentVariables("APP_");
    })
    .UseSerilog((hostingContext, loggerConfiguration) =>
        loggerConfiguration
            .ReadFrom.Configuration(hostingContext.Configuration)
            .Enrich.FromLogContext()
            .Enrich.WithExceptionDetails()
            .WriteTo.Console(new JsonFormatter())
    )
    .ConfigureWebHostDefaults(webBuilder =>
    {
        webBuilder.UseStartup<Startup>();
    });

Qing Guo - MSFT 896 Microsoft External Staff

Hi @Subir Das ,

the API fails to launch correctly in both development environments and within Linux Docker containers for production deployment

Is it launch correctly in development environment ? What's your DotNetEnv.Env.LoadMulti ? Please provide a lot more information about what you're trying to do - in particular, what project type you're using. Do you use MAC Visual Studio ? I use asp net core5 in windows Visual Studio to test the code and it works fine.

        public static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args)
    .ConfigureAppConfiguration((hostingContext, config) =>
    {
        var env = hostingContext.HostingEnvironment;
        config.Sources.Clear();
       
        config
            .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
            .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true, reloadOnChange: true)
            .AddEnvironmentVariables("APP_");
    }).ConfigureWebHostDefaults(webBuilder => {     webBuilder.UseStartup<Startup>(); }); }

Subir Das 0 Reputation points

2023-12-11T08:42:10.18+00:00
Thanks Qing Guo for checking my question.

Is it launch correctly in development environment ? No its not launching on development environment. Based on the error it looks its not getting the "applicationUrl" from the launchSetting.json after I add Sources.Clear().

What's your DotNetEnv.Env.LoadMulti ? I am using a NuGet Package "DotNetEnv Version=2.5.0.0" to access the .env files. LoadMulti is one of the method provide by the package.

Please provide a lot more information about what you're trying to do - in particular, what project type you're using. Do you use MAC Visual Studio ? I am using Windows Visual Studio 2022, the application is a ASP.NET core API running on .NET 6. The API is a basic business layer that is consumed other internal apps.
Qing Guo - MSFT 896 Reputation points Microsoft External Staff

2023-12-11T09:55:14.6366667+00:00

Hi @Subir Das ,

You can try to change the port or even restart your computer. Or try to find what is running on that port and kill the process. If you can provide a minimal reproducible example, including both the C# code and the project file, we're much more likely to be able to help you.

Subir Das 0

Hi Qing Guo,

Following is the code to replicate the scenario.

Project File-

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="DotNetEnv" Version="2.5.0" />
    <PackageReference Include="Serilog" Version="3.1.1" />
    <PackageReference Include="Serilog.AspNetCore" Version="8.0.0" />
    <PackageReference Include="Serilog.Exceptions" Version="8.4.0" />
    <PackageReference Include="Serilog.Extensions.Logging" Version="8.0.0" />
    <PackageReference Include="Serilog.Formatting.Compact" Version="2.0.0" />
    <PackageReference Include="Serilog.Settings.AppSettings" Version="2.2.2" />
    <PackageReference Include="Serilog.Settings.Configuration" Version="8.0.0" />
    <PackageReference Include="Serilog.Sinks.Console" Version="5.0.1" />
    <PackageReference Include="Swashbuckle.AspNetCore" Version="6.5.0" />
  </ItemGroup>

</Project>

Program.cs

using Serilog;
using Serilog.Events;
using Serilog.Exceptions;
using Serilog.Formatting.Json;

namespace WebApplication1
{
    public class Program
    {
        public static void Main(string[] args)
        {
            // Configure Serilog
            Log.Logger = new LoggerConfiguration()
                .MinimumLevel.Debug()
                .MinimumLevel.Override("Microsoft", LogEventLevel.Information)
                .Enrich.FromLogContext()
                .Enrich.WithExceptionDetails()
                .WriteTo.Console(new JsonFormatter())
                .CreateLogger();

            try
            {
                Log.Information("Starting web host");
                CreateHostBuilder(args).Build().Run();
            }
            catch (Exception ex)
            {
                Log.Fatal(ex, "Host terminated unexpectedly");
            }
            finally
            {
                Log.CloseAndFlush();
            }
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .ConfigureAppConfiguration((hostingContext, config) =>
            {
                var env = hostingContext.HostingEnvironment;
                config.Sources.Clear();// This is the line that looks to be the root cause; if you comment on the line, the service runs fine. But I need to run my project with this line.
                DotNetEnv.Env.LoadMulti(new[] {
                    $".env",
                    $".env.{env.EnvironmentName}"
                });                
                config
                    .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
                    .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true, reloadOnChange: true)
                    .AddEnvironmentVariables("APP_");
            })
            .UseSerilog((hostingContext, loggerConfiguration) =>
                loggerConfiguration
                    .ReadFrom.Configuration(hostingContext.Configuration)
                    .Enrich.FromLogContext()
                    .Enrich.WithExceptionDetails()
                    .WriteTo.Console(new JsonFormatter())
        )
            .ConfigureWebHostDefaults(webBuilder =>
            {
                webBuilder.UseStartup<Startup>();
            });
    }
}

Startup.cs

using DotNetEnv;

namespace WebApplication1
{
    public class Startup
    {
        private IConfiguration _configuration;
        private IWebHostEnvironment _env;

        public Startup(IConfiguration configuration, IWebHostEnvironment env)
        {
            _configuration = configuration;
            _env = env;
        }
        public void ConfigureServices(IServiceCollection services) {
            services.AddMvc(o => o.EnableEndpointRouting = false);
        }

        public void Configure(IApplicationBuilder app, IWebHostEnvironment env, IServiceProvider serviceProvider)
        {
            app.UseRouting();
            app.UseAuthentication();
            app.UseMvc();
        }
    }
}

launchSettings.json

{
  "profiles": {
    "AIProducerBackend": {
      "commandName": "Project",
      "launchBrowser": true,
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      },
      "applicationUrl": "https://localhost:5001;http://localhost:5002"
    }
  },
  "iisSettings": {
    "windowsAuthentication": false,
    "anonymousAuthentication": true,
    "iisExpress": {
      "applicationUrl": "http://localhost:56793",
      "sslPort": 44391
    }
  }
}

.env file

APP_DeploymentModel="Public"
APP_InternalUrl="http://web:8080"
APP_Azure__Database__ConnectionString="testconnection"

Qing Guo - MSFT 896 Reputation points Microsoft External Staff

2023-12-12T10:30:35.06+00:00

Hi @Subir Das ,

I test your code, and it shows the log like:

I don't meet the error like yours. And I am confused about how do you use the swagger, since the Program.cs in asp.net core 6 like: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/startup?view=aspnetcore-6.0 . Besides you can have a look at Configuration providers in .NET to know more.

1 answer

Your answer

Qing Guo - MSFT 896 Reputation points Microsoft External Staff

2023-12-11T03:26:53.4533333+00:00

Hi @Subir Das ,

the API fails to launch correctly in both development environments and within Linux Docker containers for production deployment

Is it launch correctly in development environment ? What's your DotNetEnv.Env.LoadMulti ? Please provide a lot more information about what you're trying to do - in particular, what project type you're using. Do you use MAC Visual Studio ? I use asp net core5 in windows Visual Studio to test the code and it works fine.

public static IHostBuilder CreateHostBuilder(string[] args) => Host.CreateDefaultBuilder(args) .ConfigureAppConfiguration((hostingContext, config) => { var env = hostingContext.HostingEnvironment; config.Sources.Clear(); config .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true) .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true, reloadOnChange: true) .AddEnvironmentVariables("APP_"); }).ConfigureWebHostDefaults(webBuilder => { webBuilder.UseStartup<Startup>(); }); }
Subir Das 0 Reputation points

2023-12-11T08:42:10.18+00:00

Thanks Qing Guo for checking my question.

Is it launch correctly in development environment ? No its not launching on development environment. Based on the error it looks its not getting the "applicationUrl" from the launchSetting.json after I add Sources.Clear().

What's your DotNetEnv.Env.LoadMulti ? I am using a NuGet Package "DotNetEnv Version=2.5.0.0" to access the .env files. LoadMulti is one of the method provide by the package.

Please provide a lot more information about what you're trying to do - in particular, what project type you're using. Do you use MAC Visual Studio ? I am using Windows Visual Studio 2022, the application is a ASP.NET core API running on .NET 6. The API is a basic business layer that is consumed other internal apps.
Qing Guo - MSFT 896 Reputation points Microsoft External Staff

2023-12-11T09:55:14.6366667+00:00

Hi @Subir Das ,

You can try to change the port or even restart your computer. Or try to find what is running on that port and kill the process. If you can provide a minimal reproducible example, including both the C# code and the project file, we're much more likely to be able to help you.
Qing Guo - MSFT 896 Reputation points Microsoft External Staff

2023-12-12T10:30:35.06+00:00

Hi @Subir Das ,

I test your code, and it shows the log like:

I don't meet the error like yours. And I am confused about how do you use the swagger, since the Program.cs in asp.net core 6 like: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/startup?view=aspnetcore-6.0 . Besides you can have a look at Configuration providers in .NET to know more.

Answer 1

Subir Das 0

Thank for the help. I have reverted back to use IWebHostBuilder.

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After migrating from IWebHostBuilder to IHostBuilder, the ASP.NET Core API is unable to access the 'applicationUrl' configuration from 'launchSettings.json'.

1 answer

Your answer