ABP/Swashbuckle - Generating swagger docs using Swashbuckle CLI - abp

Question

Using ABP Framework (3.3) and ASP.NET Core (3.1).
I'm attempting to generate swagger.json using Swashbuckle.AspNetCore.Cli (https://github.com/domaindrivendev/Swashbuckle.AspNetCore#retrieve-swagger-directly-from-a-startup-assembly) after compiling the application, pointing to the compiled dll using the following command:
dotnet swagger tofile --output "C:\temp\swagger" .\bin\Release\netcoreapp3.1\MyBin.dll v1
It gives me the below exception:
Unhandled exception. System.ArgumentNullException: Value cannot be null. (Parameter 'provider')
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceCollectionCommonExtensions.GetRequiredService[T](IServiceCollection services)
at System.Lazy`1.ViaFactory(LazyThreadSafetyMode mode)
at System.Lazy`1.ExecutionAndPublication(LazyHelper executionAndPublication, Boolean useDefaultConstructor)
at System.Lazy`1.CreateValue()
at System.Lazy`1.get_Value()
at Volo.Abp.AspNetCore.Mvc.AbpDataAnnotationAutoLocalizationMetadataDetailsProvider.CreateDisplayMetadata(DisplayMetadataProviderContext context)
at Microsoft.AspNetCore.Mvc.ModelBinding.Metadata.DefaultCompositeMetadataDetailsProvider.CreateDisplayMetadata(DisplayMetadataProviderContext context)
at Microsoft.AspNetCore.Mvc.ModelBinding.Metadata.DefaultModelMetadata.get_DisplayMetadata()
at Microsoft.AspNetCore.Mvc.ModelBinding.Metadata.DefaultModelMetadata.get_Order()
at Microsoft.AspNetCore.Mvc.ModelBinding.Metadata.DefaultModelMetadata.<>c.<get_Properties>b__78_0(ModelMetadata p)
at System.Linq.EnumerableSorter`2.ComputeKeys(TElement[] elements, Int32 count)
at System.Linq.EnumerableSorter`1.ComputeMap(TElement[] elements, Int32 count)
at System.Linq.EnumerableSorter`1.Sort(TElement[] elements, Int32 count)
at System.Linq.OrderedEnumerable`1.ToList()
at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
at Microsoft.AspNetCore.Mvc.ModelBinding.ModelPropertyCollection..ctor(IEnumerable`1 properties)
at Microsoft.AspNetCore.Mvc.ModelBinding.Metadata.DefaultModelMetadata.get_Properties()
at Microsoft.AspNetCore.Mvc.ModelBinding.ModelMetadataProviderExtensions.GetMetadataForProperty(IModelMetadataProvider provider, Type containerType, String propertyName)
at Microsoft.AspNetCore.Mvc.ApplicationModels.DefaultApplicationModelProvider.CreatePropertyModel(PropertyInfo propertyInfo)
at Microsoft.AspNetCore.Mvc.ApplicationModels.DefaultApplicationModelProvider.OnProvidersExecuting(ApplicationModelProviderContext context)
at Microsoft.AspNetCore.Mvc.ApplicationModels.ApplicationModelFactory.CreateApplicationModel(IEnumerable`1 controllerTypes)
at Microsoft.AspNetCore.Mvc.ApplicationModels.ControllerActionDescriptorProvider.GetDescriptors()
at Microsoft.AspNetCore.Mvc.ApplicationModels.ControllerActionDescriptorProvider.OnProvidersExecuting(ActionDescriptorProviderContext context)
at Microsoft.AspNetCore.Mvc.Infrastructure.DefaultActionDescriptorCollectionProvider.UpdateCollection()
at Microsoft.AspNetCore.Mvc.Infrastructure.DefaultActionDescriptorCollectionProvider.Initialize()
at Microsoft.AspNetCore.Mvc.Infrastructure.DefaultActionDescriptorCollectionProvider.get_ActionDescriptors()
at Microsoft.AspNetCore.Mvc.ApiExplorer.ApiDescriptionGroupCollectionProvider.get_ApiDescriptionGroups()
at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GetSwagger(String documentName, String host, String basePath)
at Swashbuckle.AspNetCore.Cli.Program.<>c.<Main>b__0_3(IDictionary`2 namedArgs) in C:\projects\ahoy\src\Swashbuckle.AspNetCore.Cli\Program.cs:line 72
at Swashbuckle.AspNetCore.Cli.CommandRunner.Run(IEnumerable`1 args) in C:\projects\ahoy\src\Swashbuckle.AspNetCore.Cli\CommandRunner.cs:line 68
at Swashbuckle.AspNetCore.Cli.CommandRunner.Run(IEnumerable`1 args) in C:\projects\ahoy\src\Swashbuckle.AspNetCore.Cli\CommandRunner.cs:line 68
at Swashbuckle.AspNetCore.Cli.Program.Main(String[] args) in C:\projects\ahoy\src\Swashbuckle.AspNetCore.Cli\Program.cs:line 111
I've tried also creating a public class as per the Swashbuckle docs, as we are using Autofac:
public class SwaggerHostFactory
{
public static IHost CreateHost()
{
return Program.CreateHostBuilder(new string[0]).Build(); //Calls the same builder that's used to run the app
}
}
The intent is to allow running this in our pipelines to auto-generate ApiClient libraries.
I'm at a bit of a loss as to how to resolve this. The swagger.json is generated at runtime perfectly fine?
Any help appreciated!

Answer 1

One way to avoid this is to make sure your program continues without these app settings
var connectionString = config["MyConnectionString"];
if (connectionString != null)
{
services.AddDbContext<AppDbContext>(options =>
options.UseSqlServer(connectionString));
}

Answer 2

You can get the Swagger.json in a simple way without Swagger CLI.
Run your web with the dotnet command:
dotnet MyCompanyName.MyProjectName.Web.dll
Then download the Swagger.json with the following Powershell command:
Invoke-WebRequest -Uri https://localhost:5001/swagger/v1/swagger.json -OutFile c:\temp\swagger.json