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Issue with NSwag.MSBuild and .NET 5

See original GitHub issue

We are using NSWag.MSBuild (v 13.7.4) to generate a TypeScript client from our ASP.NET Core Api. When I build the .NET Core app with .NET 5 RC 1, I get the following exception when executing NSWag:

System.InvalidOperationException: No service for type 'Microsoft.AspNetCore.Mvc.ApiExplorer.IApiDescriptionGroupCollectionProvider' has been registered.
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)
   at NSwag.Commands.Generation.AspNetCore.AspNetCoreToSwaggerCommand.GenerateDocumentWithApiDescriptionAsync(AssemblyLoader assemblyLoader, IServiceProvider serviceProvider, String currentWorkingDirectory) in C:\projects\nswag\src\NSwag.Commands\Commands\Generation\AspNetCore\AspNetCoreToOpenApiCommand.cs:line 296
   at NSwag.Commands.Generation.AspNetCore.AspNetCoreToSwaggerCommand.GenerateDocumentAsync(AssemblyLoader assemblyLoader, IServiceProvider serviceProvider, String currentWorkingDirectory) in C:\projects\nswag\src\NSwag.Commands\Commands\Generation\AspNetCore\AspNetCoreToOpenApiCommand.cs:line 280
   at NSwag.Commands.Generation.AspNetCore.AspNetCoreToSwaggerCommand.RunIsolatedAsync(AssemblyLoader assemblyLoader) in C:\projects\nswag\src\NSwag.Commands\Commands\Generation\AspNetCore\AspNetCoreToOpenApiCommand.cs:line 312
   at NSwag.Commands.IsolatedCommandBase`1.IsolatedCommandAssemblyLoader`1.Run(String commandType, String commandData, String[] assemblyPaths, String[] referencePaths) in C:\projects\nswag\src\NSwag.Commands\Commands\IsolatedCommandBase.cs:line 76
   at NSwag.Commands.IsolatedCommandBase`1.<>c__DisplayClass17_0.<RunIsolatedAsync>b__0() in C:\projects\nswag\src\NSwag.Commands\Commands\IsolatedCommandBase.cs:line 61
   at System.Threading.Tasks.Task`1.InnerInvoke()
   at System.Threading.Tasks.Task.<>c.<.cctor>b__274_0(Object obj)
   at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
--- End of stack trace from previous location where exception was thrown ---
   at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot, Thread threadPoolThread)
--- End of stack trace from previous location where exception was thrown ---
   at NSwag.Commands.IsolatedCommandBase`1.RunIsolatedAsync(String configurationFile) in C:\projects\nswag\src\NSwag.Commands\Commands\IsolatedCommandBase.cs:line 61
   at NSwag.Commands.IsolatedSwaggerOutputCommandBase`1.RunAsync(CommandLineProcessor processor, IConsoleHost host) in C:\projects\nswag\src\NSwag.Commands\Commands\IsolatedSwaggerOutputCommandBase.cs:line 51
   at NSwag.Commands.Generation.AspNetCore.AspNetCoreToSwaggerCommand.RunAsync(CommandLineProcessor processor, IConsoleHost host) in C:\projects\nswag\src\NSwag.Commands\Commands\Generation\AspNetCore\AspNetCoreToOpenApiCommand.cs:line 95
   at NSwag.Commands.NSwagDocumentBase.GenerateSwaggerDocumentAsync() in C:\projects\nswag\src\NSwag.Commands\NSwagDocumentBase.cs:line 280
   at NSwag.Commands.NSwagDocument.ExecuteAsync() in C:\projects\nswag\src\NSwag.Commands\NSwagDocument.cs:line 81
   at NSwag.Commands.Document.ExecuteDocumentCommand.ExecuteDocumentAsync(IConsoleHost host, String filePath) in C:\projects\nswag\src\NSwag.Commands\Commands\Document\ExecuteDocumentCommand.cs:line 86
   at NSwag.Commands.Document.ExecuteDocumentCommand.RunAsync(CommandLineProcessor processor, IConsoleHost host) in C:\projects\nswag\src\NSwag.Commands\Commands\Document\ExecuteDocumentCommand.cs:line 32
   at NConsole.CommandLineProcessor.ProcessSingleAsync(String[] args, Object input)
   at NConsole.CommandLineProcessor.ProcessAsync(String[] args, Object input)
   at NConsole.CommandLineProcessor.Process(String[] args, Object input)
   at NSwag.Commands.NSwagCommandProcessor.Process(String[] args) in C:\projects\nswag\src\NSwag.Commands\NSwagCommandProcessor.cs:line 56

I first use the aspNetCoreToOpenApi document generator, and based on that the openApiToTypeScriptClient code generator. This is my nswag.json file:

{
    "runtime": "$(runtime)",
    "defaultVariables": null,
    "documentGenerator": {
      "aspNetCoreToOpenApi": {
        "project": null,
        "msBuildProjectExtensionsPath": null,
        "configuration": null,
        "runtime": null,
        "targetFramework": null,
        "noBuild": false,
        "verbose": true,
        "workingDirectory": null,
        "requireParametersWithoutDefault": false,
        "apiGroupNames": null,
        "defaultPropertyNameHandling": "Default",
        "defaultReferenceTypeNullHandling": "NotNull",
        "defaultDictionaryValueReferenceTypeNullHandling": "NotNull",
        "defaultResponseReferenceTypeNullHandling": "NotNull",
        "defaultEnumHandling": "Integer",
        "flattenInheritanceHierarchy": false,
        "generateKnownTypes": true,
        "generateEnumMappingDescription": false,
        "generateXmlObjects": false,
        "generateAbstractProperties": false,
        "generateAbstractSchemas": true,
        "ignoreObsoleteProperties": false,
        "allowReferencesWithProperties": false,
        "excludedTypeNames": [],
        "serviceHost": null,
        "serviceBasePath": null,
        "serviceSchemes": [],
        "infoTitle": "Title",
        "infoDescription": null,
        "infoVersion": "1.0.0",
        "documentTemplate": null,
        "documentProcessorTypes": [],
        "operationProcessorTypes": [],
        "typeNameGeneratorType": null,
        "schemaNameGeneratorType": null,
        "contractResolverType": null,
        "serializerSettingsType": null,
        "useDocumentProvider": false,
        "documentName": "v1",
        "aspNetCoreEnvironment": null,
        "createWebHostBuilderMethod": null,
        "startupType": null,
        "allowNullableBodyParameters": true,
        "output": "swagger.json",
        "outputType": "Swagger2",
        "assemblyPaths": ["myAssembly.dll"],
        "assemblyConfig": null,
        "referencePaths": [],
        "useNuGetCache": false
      }
    },
    "codeGenerators": {
      "openApiToTypeScriptClient": {
        "className": "{controller}ApiProxy",
        "moduleName": "",
        "namespace": "",
        "typeScriptVersion": 4.0,
        "template": "Angular",
        "promiseType": "Promise",
        "httpClass": "HttpClient",
        "withCredentials": false,
        "useSingletonProvider": true,
        "injectionTokenType": "InjectionToken",
        "rxJsVersion": 6.6,
        "dateTimeType": "Date",
        "nullValue": "Undefined",
        "generateClientClasses": true,
        "generateClientInterfaces": false,
        "generateOptionalParameters": true,
        "exportTypes": true,
        "wrapDtoExceptions": false,
        "exceptionClass": "SwaggerException",
        "clientBaseClass": "ApiProxyBase",
        "wrapResponses": false,
        "wrapResponseMethods": [],
        "generateResponseClasses": true,
        "responseClass": "SwaggerResponse",
        "protectedMethods": [],
        "configurationClass": null,
        "useTransformOptionsMethod": true,
        "useTransformResultMethod": true,
        "generateDtoTypes": true,
        "operationGenerationMode": "MultipleClientsFromOperationId",
        "markOptionalProperties": true,
        "generateCloneMethod": false,
        "typeStyle": "Class",
        "classTypes": [],
        "extendedClasses": [],
        "extensionCode": "nswag.extensions.ts",
        "generateDefaultValues": true,
        "excludedTypeNames": [],
        "excludedParameterNames": [],
        "handleReferences": false,
        "generateConstructorInterface": true,
        "convertConstructorInterfaceData": false,
        "importRequiredTypes": true,
        "useGetBaseUrlMethod": false,
        "baseUrlTokenName": "API_BASE_URL",
        "queryNullValue": "",
        "inlineNamedDictionaries": false,
        "inlineNamedAny": false,
        "templateDirectory": null,
        "typeNameGeneratorType": null,
        "propertyNameGeneratorType": null,
        "enumNameGeneratorType": null,
        "serviceHost": null,
        "serviceSchemes": null,
        "output": "api.ts"
      }
    }
  }

The command to execute the generation is as follow:

dotnet ./packages/NSwag.MSBuild/tools/NetCore31/dotnet-nswag.dll run nswag.json "/variables:runtime=NetCore31"

I saw that there is a related issue #3026, but the workaround with NSwag.AspNetCore doesn’t work for us, as our Api doesn’t know anything about Swagger and the client generation. The client generation is fully part of a build script.

If I generate the swagger.json file with NSwag.AspNetCore and only execute the openApiToTypeScriptClient based on the file, it works, so the issue seems to be in aspNetCoreToOpenApi. We use the same setup in multiple projects targeting .NET Core 3.1 without any issues.

Is there a problem with my setup or is this an issue with NSwag.MSBuild and .NET 5?

Thanks for looking into it 😃