Compatibility Issues with .NET 8 In-Process Model

[abaazzi]

Hi, The last version is compatible only with isolated worker model in azure function, is there something planned for in-process model?

[vitalybibikov]

Hello, at the moment no, as In-Process model is going to be deprecated beginning 10 November 2026.

If there will be enough requests, I will implement it, though I need to understand how many people need it.

[kkdubey]

@vitalybibikov I'm using in-process model in multiple solution. getting compatibility issue after upgrade to .Net 8

[jcoolsen]

We are moving to .NET 8 because of the end-of-support for .NET 6/7. Switching to isolated model is too large a task for us at the moment. Since this project (v4) does not currently support the in-process model, we must stay at v3. Unfortunately there is a new issue with JsonSerializerOptions in .NET 8 that breaks v3. The issue is described here: https://github.com/dotnet/aspnetcore/issues/55692 with the simple solution/work-around noted in this comment: https://github.com/dotnet/aspnetcore/issues/55692#issuecomment-2392448375 It occurs in the AddSwashBuckle method: If version 3 could be updated with the TypeInfoResolver initialized on JsonSerializerOptions in this mehtod, that would be great.

[jcoolsen]

Wow, the referenced issue was deleted just now! That makes no sense to me. Anyway I had it open in another tab and was able to save a copy of the page here: Dotnet 8 JsonSerializerOptions Breaking change · Issue #55692 · dotnet_aspnetcore.pdf The last comment has the solution.

EDIT: ... and now it's undeleted. Oh, well.

[fahdalaoui]

That's so needed in our project that has multiple micro services that use in-process model

we can't migrate all the project to .Net 8 and to be isolated model in specific

[AyoubOd]

Hi, I’m facing the same issue. We have nearly 20 projects that rely on the in-process model, so it would be really helpful if support for the latest version, which is currently compatible only with the isolated worker model in Azure Functions, could be added

[senthilkcg]

We are also facing the same issue in .Net8 Inproc mode. Since we have time till 2026 for inproc, could you please release the fix for InProc mode ?

[jvmlet]

Same here, we are migrating in-proc AZ functions to dotnet8 in-proc support. Please support this as well. Thanks

[jvmlet]

@vitalybibikov , can you please at least patch the 3.3.2 by changing

SystemTextJsonOutputFormatter implementationInstance = new SystemTextJsonOutputFormatter(new JsonSerializerOptions());

to

SystemTextJsonOutputFormatter implementationInstance = new SystemTextJsonOutputFormatter(new JsonSerializerOptions({
TypeInfoResolver = new DefaultJsonTypeInfoResolver(); 
}));

in AddSwashBuckle method .

[jcoolsen]

Our current workaround may be helpful for some of you.

    internal class SwashbuckleStartup : FunctionsStartup {
        public override void Configure(IFunctionsHostBuilder builder) {
            // https://github.com/vitalybibikov/AzureExtensions.Swashbuckle/issues/117
            // https://github.com/dotnet/aspnetcore/issues/55692
            // builder.AddSwashBuckle(Assembly.GetExecutingAssembly());
             AddSwashBuckleCustom(builder, Assembly.GetExecutingAssembly());
        }

        public static IFunctionsHostBuilder AddSwashBuckleCustom(IFunctionsHostBuilder builder, Assembly assembly, Action<SwaggerDocOptions> configureDocOptionsAction = null) {
            AddSwashBuckleCustom(builder.Services, assembly, configureDocOptionsAction);
            return builder;
        }

        public static IServiceCollection AddSwashBuckleCustom(IServiceCollection services, Assembly assembly, 
            Action<SwaggerDocOptions> configureDocOptionsAction = null, IWebJobsBuilder webJobsBuilder = null) {

            webJobsBuilder ??= services.AddWebJobs(_ => { });

            webJobsBuilder.AddExtension<SwashbuckleConfig>()
                .BindOptions<SwaggerDocOptions>()
                .ConfigureOptions<SwaggerDocOptions>((configuration, section, options) => configureDocOptionsAction?.Invoke(options));

            services.AddSingleton<IModelMetadataProvider>(new EmptyModelMetadataProvider());
            services.AddSingleton(new SwashBuckleStartupConfig {
                Assembly = assembly
            });

            var formatter = new SystemTextJsonOutputFormatter(new JsonSerializerOptions() {
                TypeInfoResolver = new DefaultJsonTypeInfoResolver() // This is required in .NET 8 but is not part of the SwashBuckle v3 implementation.
            });
            services.AddSingleton<IOutputFormatter>(formatter);

            // Below is reflection implementation of this:
            // services.AddSingleton<IApiDescriptionGroupCollectionProvider, FunctionApiDescriptionProvider>();

            Type providerInterfaceType = typeof(IApiDescriptionGroupCollectionProvider);
            Type providerType = typeof(SwashBuckleStartupExtension).Assembly.GetType("AzureFunctions.Extensions.Swashbuckle.SwashBuckle.Providers.FunctionApiDescriptionProvider");

            MethodInfo method=typeof(ServiceCollectionServiceExtensions).GetMethod(nameof(ServiceCollectionServiceExtensions.AddSingleton), 2,
                BindingFlags.Static | BindingFlags.Public, null, new Type[] { typeof(IServiceCollection) }, null);

            MethodInfo genericMethod = method.MakeGenericMethod(providerInterfaceType, providerType);
            genericMethod.Invoke(null, new object[] { services });

            return services;
        }
    }