Add-Migration InitialCreate throws an exception, but is successful

Question

Add-Migration InitialCreate throws an exception, but is successful

David Thielen 3,211

When I run Add-Migration InitialCreate it successfully creates the EF classes. But it also throws the following exception:

PM> Add-Migration InitialCreate  -context TrackingDbContext
Build started...
Build succeeded.
{"EventId":0,"LogLevel":"Information","Category":"LouisHowe.web.Program","Message":"Application starting up","State":{"Message":"Application starting up","{OriginalFormat}":"Application starting up"}}
{"EventId":0,"LogLevel":"Critical","Category":"LouisHowe.web.Program","Message":"Unhandled exception in Main()","Exception":"Microsoft.Extensions.Hosting.HostAbortedException: The host was aborted.    at Microsoft.Extensions.Hosting.HostFactoryResolver.HostingListener.ThrowHostAborted()    at Microsoft.Extensions.Hosting.HostFactoryResolver.HostingListener.OnNext(KeyValuePair\u00602 value)    at System.Diagnostics.DiagnosticListener.Write(String name, Object value)    at Microsoft.Extensions.Hosting.HostBuilder.ResolveHost(IServiceProvider serviceProvider, DiagnosticListener diagnosticListener)    at Microsoft.Extensions.Hosting.HostApplicationBuilder.Build()    at Microsoft.AspNetCore.Builder.WebApplicationBuilder.Build()    at LouisHowe.web.Program.Main(String[] args) in C:\\Git\\LouisHowe\\LouisHowe.web\\Program.cs:line 220","State":{"Message":"Unhandled exception in Main()","{OriginalFormat}":"Unhandled exception in Main()"}}
To undo this action, use Remove-Migration.
PM>

What's going on here? And how do I avoid this exception?

thanks - dave

Wenbin Geng 741 Reputation points Microsoft External Staff

2023-10-05T09:58:28.8933333+00:00

Hi, this error message tells you that there is an unhandled exception in the Main() method. Can you share your Main() method? Also, does this program run perfectly before that kind of migration?
David Thielen 3,211 Reputation points

2023-10-06T17:48:57.69+00:00
@Wenbin Geng The program runs fine. This only occurs when creating the migration and it appears that the migration successfully completes, then it is executing main for some reason and it throws this exception.

To repeat, main() runs fine in normal use, it's only creating the migration that this is thrown.

It throws it on the call:

var app = builder.Build();
Wenbin Geng 741 Reputation points Microsoft External Staff

2023-10-09T06:43:23.4+00:00

Hi. I performed the corresponding codefirst migration in asp.net core and no such error occurred. I'm using .net 6.0 and the corresponding nuget package version as follows:

If you are using older versions related to ef core nuget you can try updating them to the latest version. If this still doesn't work, please provide more detailed information, such as your entity class and the nuget package version related to EF Core used, so that you can reproduce this error.
David Thielen 3,211 Reputation points

2023-10-10T20:40:42.7+00:00

@Wenbin Geng Good suggestion, but no luck. I upgraded to the latest version of everything. Still get the exception.

And again, it builds the migration files fine. I can build the databases. So this happens after everything needed completes.

And why would migration be running Main() anyways???

thanks - dave
Wenbin Geng 741 Reputation points Microsoft External Staff

2023-10-11T07:23:16.3833333+00:00

Hi. Entity Framework (EF) Core passes through the main program (Program.cs) and startup configuration (Startup.cs) of the ASP.NET Core application during migration because it needs to perform database migration in a running environment. This environment is usually established when the application starts.

Program.cs is the entry point for the entire application. Here, the application creates a web host builder (WebApplication.CreateBuilder(args)) and uses it to configure the service and build the host.

This host will be created when the application starts and becomes the application's runtime environment.

Startup.cs contains the code to configure the application. Here, you can configure various middleware, services, and request pipelines.

Migration to EF Core usually occurs at the startup of the application because it requires a runtime environment to perform the migration operation.

So, every time you run an EF Core migration, it creates an application host (starting from Program.cs) and performs migration operations based on the configuration (starting from the configuration in Startup.cs).
David Thielen 3,211 Reputation points

2023-10-11T14:00:05.5266667+00:00

@Wenbin Geng Thank you for the explanation as to why Main() is called. That makes sense.

As to the exception, I don't like that it is thrown. But the migration is successful and so, not worth further effort to figure out.

thanks - dave
Ilya Oparin 0 Reputation points

2023-11-06T15:22:13.2166667+00:00

Hey, @Wenbin Geng , looks like I'm having the similar issue, when trying to run Update-Database command from my Visual Studio PM Console.
I am using Microsoft.EntityFrameworkCore.Tools package 7.0.13 version, which is now the latest. What I don't like much is that specifically for running database update I now have to have catch (HostAbortedException ex) block in my Main method. Whether this exception is caught or not, the database update works fine, but catching this exception looks like a workaround. From your answer above I got the fact, that in some cases EFCore has to run some part of host settings related stuff in order to construct DbContext correctly. But is it also part of the built-in EFCore behaviour, that after finishing db update (or migration creation in @David Thielen 's case) the exception should be thrown? If not, then it seems I have some misconfigurations and could give you more details, if needed.
Fun fact: I am 99% sure, that when I first ran Update-Database today, it finished okay with no exception shown, but then I spend a couple of hours trying to find the reason with no success. So, I am only left with a feeling that it occurs every time now.
David Thielen 3,211 Reputation points

2023-11-06T16:57:10.7233333+00:00

@Ilya Oparin It ran with no exceptions for months for me. And then this started happening. Sounds like the same for you.
Ilya Oparin 0 Reputation points

2023-11-07T06:47:13.68+00:00

@David Thielen did you find any solution or just let it be thrown/caught?
David Thielen 3,211 Reputation points

2023-11-07T13:00:36.0766667+00:00

@Ilya Oparin I just ignore it. I get it in the Package Manager Console and it happens after the migration files are generated.
Ilya Oparin 0 Reputation points

2023-11-08T08:15:13.3433333+00:00

@David Thielen thanks, got it. However still would like to hear from @Wenbin Geng on the question above

Your answer

Wenbin Geng 741 Reputation points Microsoft External Staff

2023-10-05T09:58:28.8933333+00:00

Hi, this error message tells you that there is an unhandled exception in the Main() method. Can you share your Main() method? Also, does this program run perfectly before that kind of migration?
David Thielen 3,211 Reputation points

2023-10-06T17:48:57.69+00:00

@Wenbin Geng The program runs fine. This only occurs when creating the migration and it appears that the migration successfully completes, then it is executing main for some reason and it throws this exception.

To repeat, main() runs fine in normal use, it's only creating the migration that this is thrown.

It throws it on the call:

var app = builder.Build();
Wenbin Geng 741 Reputation points Microsoft External Staff

2023-10-09T06:43:23.4+00:00

Hi. I performed the corresponding codefirst migration in asp.net core and no such error occurred. I'm using .net 6.0 and the corresponding nuget package version as follows:

If you are using older versions related to ef core nuget you can try updating them to the latest version. If this still doesn't work, please provide more detailed information, such as your entity class and the nuget package version related to EF Core used, so that you can reproduce this error.
David Thielen 3,211 Reputation points

2023-10-10T20:40:42.7+00:00

@Wenbin Geng Good suggestion, but no luck. I upgraded to the latest version of everything. Still get the exception.

And again, it builds the migration files fine. I can build the databases. So this happens after everything needed completes.

And why would migration be running Main() anyways???

thanks - dave
Wenbin Geng 741 Reputation points Microsoft External Staff

2023-10-11T07:23:16.3833333+00:00

Hi. Entity Framework (EF) Core passes through the main program (Program.cs) and startup configuration (Startup.cs) of the ASP.NET Core application during migration because it needs to perform database migration in a running environment. This environment is usually established when the application starts.

Program.cs is the entry point for the entire application. Here, the application creates a web host builder (WebApplication.CreateBuilder(args)) and uses it to configure the service and build the host.

This host will be created when the application starts and becomes the application's runtime environment.

Startup.cs contains the code to configure the application. Here, you can configure various middleware, services, and request pipelines.

Migration to EF Core usually occurs at the startup of the application because it requires a runtime environment to perform the migration operation.

So, every time you run an EF Core migration, it creates an application host (starting from Program.cs) and performs migration operations based on the configuration (starting from the configuration in Startup.cs).
David Thielen 3,211 Reputation points

2023-10-11T14:00:05.5266667+00:00

@Wenbin Geng Thank you for the explanation as to why Main() is called. That makes sense.

As to the exception, I don't like that it is thrown. But the migration is successful and so, not worth further effort to figure out.

thanks - dave
Ilya Oparin 0 Reputation points

2023-11-06T15:22:13.2166667+00:00

Hey, @Wenbin Geng , looks like I'm having the similar issue, when trying to run Update-Database command from my Visual Studio PM Console.
I am using Microsoft.EntityFrameworkCore.Tools package 7.0.13 version, which is now the latest. What I don't like much is that specifically for running database update I now have to have catch (HostAbortedException ex) block in my Main method. Whether this exception is caught or not, the database update works fine, but catching this exception looks like a workaround. From your answer above I got the fact, that in some cases EFCore has to run some part of host settings related stuff in order to construct DbContext correctly. But is it also part of the built-in EFCore behaviour, that after finishing db update (or migration creation in @David Thielen 's case) the exception should be thrown? If not, then it seems I have some misconfigurations and could give you more details, if needed.
Fun fact: I am 99% sure, that when I first ran Update-Database today, it finished okay with no exception shown, but then I spend a couple of hours trying to find the reason with no success. So, I am only left with a feeling that it occurs every time now.
David Thielen 3,211 Reputation points

2023-11-06T16:57:10.7233333+00:00

@Ilya Oparin It ran with no exceptions for months for me. And then this started happening. Sounds like the same for you.
Ilya Oparin 0 Reputation points

2023-11-07T06:47:13.68+00:00

@David Thielen did you find any solution or just let it be thrown/caught?
David Thielen 3,211 Reputation points

2023-11-07T13:00:36.0766667+00:00

@Ilya Oparin I just ignore it. I get it in the Package Manager Console and it happens after the migration files are generated.
Ilya Oparin 0 Reputation points

2023-11-08T08:15:13.3433333+00:00

@David Thielen thanks, got it. However still would like to hear from @Wenbin Geng on the question above

Share via

Add-Migration InitialCreate throws an exception, but is successful

Your answer