"Exception has been thrown by the target of an invocation" error when injecting Amazon S3 Service in ASP .Net Core constructor - asp.net-core

Question

I have an ASP .Net Core 2.2 Web API. In it, I have an endpoint where the front-end (Angular app) can send a file to the API, and the API in turn uploads this file to an Amazon S3 bucket (us-east-1 region).
This works perfectly while I'm debugging in Visual Studio, but when I publish to my server (Windows Server 2016) I get the following exception:
Error: Exception has been thrown by the target of an
invocation. at System.RuntimeMethodHandle.InvokeMethod(Object
target, Object[] arguments, Signature sig, Boolean constructor,
Boolean wrapExceptions) at
System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags
invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at Amazon.Extensions.NETCore.Setup.ClientFactory.CreateClient(Type
serviceInterfaceType, AWSCredentials credentials, ClientConfig config)
at
Amazon.Extensions.NETCore.Setup.ClientFactory.CreateServiceClient(ILogger
logger, Type serviceInterfaceType, AWSOptions options) at
Amazon.Extensions.NETCore.Setup.ClientFactory.CreateServiceClient(IServiceProvider
provider) at
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitFactory(FactoryCallSite
factoryCallSite, ServiceProviderEngineScope scope) at
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor2.VisitCallSite(IServiceCallSite
callSite, TArgument argument) at
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite
scopedCallSite, ServiceProviderEngineScope scope) at
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitSingleton(SingletonCallSite
singletonCallSite, ServiceProviderEngineScope scope) at
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor2.VisitCallSite(IServiceCallSite
callSite, TArgument argument) at
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite
constructorCallSite, ServiceProviderEngineScope scope) at
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor2.VisitCallSite(IServiceCallSite
callSite, TArgument argument) at
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite
scopedCallSite, ServiceProviderEngineScope scope) at
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitSingleton(SingletonCallSite
singletonCallSite, ServiceProviderEngineScope scope) at
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor2.VisitCallSite(IServiceCallSite
callSite, TArgument argument) at
Microsoft.Extensions.DependencyInjection.ServiceLookup.DynamicServiceProviderEngine.<>c__DisplayClass1_0.
b__0(ServiceProviderEngineScope scope) at
Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.GetService(Type
serviceType, ServiceProviderEngineScope serviceProviderEngineScope)
at
Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type
serviceType) at
Microsoft.Extensions.DependencyInjection.ActivatorUtilities.GetService(IServiceProvider
sp, Type type, Type requiredBy, Boolean isDefaultParameterRequired)
at lambda_method(Closure , IServiceProvider , Object[] ) at
Microsoft.AspNetCore.Mvc.Controllers.ControllerActivatorProvider.<>c__DisplayClass4_0.
b__0(ControllerContext controllerContext) at Microsoft.AspNetCore.Mvc.Controllers.ControllerFactoryProvider.<>c__DisplayClass5_0.
g__CreateController|0(ControllerContext
controllerContext) at
Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(State&
next, Scope& scope, Object& state, Boolean& isCompleted) at
Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeInnerFilterAsync()
at
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeNextResourceFilter()
at
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Rethrow(ResourceExecutedContext
context) at
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(State& next,
Scope& scope, Object& state, Boolean& isCompleted) at
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeFilterPipelineAsync()
at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeAsync()
at Microsoft.AspNetCore.Routing.EndpointMiddleware.Invoke(HttpContext
httpContext) at
Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.Invoke(HttpContext
httpContext) at
PropWorx.API.Middlewares.TenantIdentifier.Invoke(HttpContext
httpContext, SharedContext sharedContext) in
C:\Users\fabsr\source\repos\PropWorx.API\PropWorx.API\Middlewares\TenantIdentifier.cs:line
73 at
Microsoft.AspNetCore.Builder.Extensions.MapWhenMiddleware.Invoke(HttpContext
context) at
Microsoft.AspNetCore.Builder.Extensions.MapWhenMiddleware.Invoke(HttpContext
context) at
Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext
context) at
Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext
httpContext) at
Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext
httpContext, ISwaggerProvider swaggerProvider) at
Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext
context) at
Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.Invoke(HttpContext
context)
I've created the "credentials" file in the %UserProfile%.aws folder.
I've added the following two NuGet packages to the project:
AWSSDK.Extensions.NETCore.Setup
AWSSDK.S3
I have this in my Startup.cs:
public void ConfigureServices(IServiceCollection services)
{
services.AddAWSService<IAmazonS3>();
services.AddSingleton<IS3Service, S3Service>();
}
S3Service.cs looks like this:
public class S3Service : IS3Service
{
private readonly IAmazonS3 _client;
public S3Service(IAmazonS3 client)
{
_client = client;
}
// Some methods to upload and delete objects... not important
}
I inject this service to one of my controllers:
public class FilesController : ControllerBase
{
private readonly IS3Service _s3Service;
public FilesController(IS3Service s3Service)
{
_s3Service = s3Service;
}
// Some actions to receive the file... not important
}
The error happens as soon as I call any action in this controller. In fact, the error appears to be happening when the S3Service is injected into the controller's constructor. If I remove the constructor injection, i.e.:
public class FilesController : ControllerBase
{
private readonly IS3Service _s3Service;
public FilesController()
{
}
// Some actions to receive the file... not important
}
The error goes away (but of course doesn't work properly)
Any ideas? Like I said, this works perfectly on my laptop while debugging in VS2017. But it doesn't work when published to the server. All other controllers in the API work fine. It appears to be a problem at the point of injecting the S3Service in the constructor...

Answer 1

I kept it simple. In my local machines, I was keeping the keys in the user-secrets and on the prod server I was keeping those in the IIS configuration file. and was just accessing these values from ConfigurationManager. Basically it was using the new AmazonS3Client(string, string, string) syntax. Also I was using a farily older version of .net core there is a possibility that the issue was fixed. Check out this which seems working.

Answer 2

I changed my code to get IAmazonS3 insatance not through but directly instantiating it inside my IS3Serice method and it worked. Somehow the DI is not able to pick config values and that's why was not able to resolve the object.
You can get some information about this from here
I went through the actual documentation
https://docs.aws.amazon.com/sdk-for-net/v3/developer-guide/net-dg-config-netcore.html
and found following:
If you look at the Debug tab in your project's properties, you can see this file is set to Development. This works great for local testing because you can put your configuration in the appsettings.Development.json file, which is read-only during local testing. When you deploy an Amazon EC2 instance that has EnvironmentName set to Production, this file is ignored and the AWS SDK for .NET falls back to the IAM credentials and region configured for the Amazon EC2 instance.
So this could be the reason that your initial configurations didn't work as you were trying to use access keys on production.
Also have a look at following answer
How to set credentials on AWS SDK on NET Core?