.NET Core – DRNJ

Docker CLI and Compose Information Message

April 3, 2024

From the Docker CLI when using a Docker Context for Azure and you do

docker compose up

You get the following message

Docker Compose's integration for ECS and ACI will be retired in November 2023. Learn more: https://docs.docker.com/go/compose-ecs-eol/

What that means, I think, is that Docker have stopped supported Compose from the Docker CLI. I’m not sure if you can use/is-supported Docker Compose from the azure CLI

Docker Containers and Azure – An Introduction

April 3, 2024

The Problem

I wanted to start using Docker Containers on Azure as I had been using them locally for ages and found them very useful. I had progressed to using Docker Compose for multi-container apps and even for single-container apps as the compose-file contained all the information needed to run the container rather than remember port-mappings, volumes etc for the docker run command.

However….the documentation for containers on Azure is confusing. It’s simple to get a container up and running but it’s not so simple to understand what/where/why. Hence this article

Serilog in .Net Core 6

September 25, 2022

The Problem

I wanted to add Serilog to a WebAPI using .Net Core 6. The “startup” has changed from .Net Core 3 and the “wiring” up of services so it wasn’t clear to me how to get it all working.

The Solution

After some head scratching and searching I work out that you needed from this article and this article (thanks to the authers)

So I created a method

protected void ConfigureLogging(WebApplicationBuilder appBuilder)
{
appBuilder.Host.UseSerilog((ctx, lc) => lc
.ReadFrom.Configuration(ctx.Configuration)
.WriteTo.Console()
);

}

This method is called from the program.cs “startup” code.

Placed the following in appsetttings.json

{
"Serilog": {
"MinimumLevel": {
"Default": "Information",
"Override": {
"Microsoft": "Warning",
"DRNJ": "Debug",
"Microsoft.Hosting.Lifetime": "Information"
}
},
"Filter": [
{
"Name": "ByExcluding",
"Args": {
"expression": "@mt = 'An unhandled exception has occurred while executing the request.'"
}
}
],
"WriteTo": [
{ "Name": "Console" },
{
"Name": "File",
"Args": {
"path": "c:\\temp\\log\\apilog-.txt",
"rollingInterval": "Day"
}
}
]
},
"AllowedHosts": "*"
}

And, voila, it all worked

Serilog And .Net Core 3.1

September 25, 2022

The Problem

I found configuring Serilog for .Net Core quite complex and poorly documented. All I wanted to do was to pipe log messages to a text file.

The Solution

After some searching I found this project.

The following code was added to Program.cs

public static void Main(string[] args)
{ 
CreateHostBuilderWithSimpleSerilog(args).Build().Run();
}

public static IHostBuilder CreateHostBuilderWithSimpleSerilog(string[] args) =>
Host.CreateDefaultBuilder(args)
.ConfigureLogging((context, builder) =>
{
//----------------------------------------------------------------------
// Simple SeriLog |
// Using https://github.com/serilog/serilog-extensions-logging-file |
//----------------------------------------------------------------------
builder.AddFile(context.Configuration.GetLoggerConfiguration());
})
.ConfigureWebHostDefaults(webBuilder =>
{
if (bool.Parse(Environment.GetEnvironmentVariable("USE_HTTP_SYS") ?? "false"))
{
webBuilder.UseHttpSys(options =>
{
options.Authentication.Schemes = AuthenticationSchemes.None;
options.Authentication.AllowAnonymous = true;
});
}
webBuilder.UseStartup<Startup>();
});

Along with

 public static class StartupConfiguration
    {

        public static IConfigurationSection GetLoggerConfiguration(this IConfiguration config)
        {
            return config.GetSection("Logging");
        }

        public static T Get<T>(this IConfiguration config, string name)
        {
            return config
                 .GetSection(name)
                 .Get<T>();
        }
    }

And then the Appsettings.json section for logging

"Logging": {
"OutputTemplate": "{Timestamp:o} {RequestId,13} [{Level:u3}] {Message} Properties: {Properties:j} ({EventId:x8}){NewLine}{Exception}",
"PathFormat": "Logs/MyLog-{Date}.log",
"MinimumLevel": "Information",
"LogLevel": {
"Default": "Warning",
"Microsoft": "Warning",
"Microsoft.Hosting.Lifetime": "Warning",
"Microsoft.EntityFrameworkCore": "Warning"
}
}

And Voila. Logging to file works and Dependency Injection of Serilog is wired up too.

NHIbernate, Sybase and .NET Core

June 28, 2021

The Problem

I was working on a system utilising .NET 4.x and Sybase. This combination is not supported by Entity Framework so NHibernate was used.

It was planned to migrate the project to .NET Core, however a number of issues were encountered ustilising NHibernate.

Much investigation was performed, espcially using Resharper to disassemble the Sybase driver

The solution is shown below. Voila, you can use .NET Core and NHibernate and Sybase.

Solution Attempt Number 1

Code

Create WebAPI project on DotNet Core 3.1
Add references to NHibernate 5.2.7

Errors

Discussion

It appears that the NHibernate code cannot find the the Sybase ASE driver Sybase.ADONet2.AseClient installed as part of the nuget package

Solution Attempt Number 2

Code

As per Verrsion 1 but with

NHibernate 5.2.7 Source code downloaded and .csproj added to solution and references instead of NHibernate nuget package (so can step through code)
Reference added to Sysbase DLLs

Errors

Discussion

An exception is thrown in the Sybase.AdoNet2.ASeClient.dll in the constructor which calls LoadLibraries():

NB Disassembly of the driver done by ReSharper

The error is thrown at the line 252 on the Directory.GetAccessControl method – this is not supported in .Net Core:

https://stackoverflow.com/questions/41584932/support-for-file-security-in-net-core

The “workaround” suggested does not appear to work within the context of the Driver (not known why but driver might run in a restricted execution context). This article also discusses the driver error and that some System.IO methods have been removed in dotnetcore.

The Real Solution

Code

Add AdoNetCore.AseClient nuget package – this is a 3rd party Sybase ASE driver
Reference NHibernate nuget version 5.2.7
Add Driver classes as below

These files are “driver” classes customised to use the AdoNetCore.AseClient driver. These are “copies” of the equivalent files in the NHibernate source code with the following modifications

The above specification for connection.driver_class is necessary as “full assembly specification” giving assembly name and class name otherwise NHibernate doesn’t know in which DLL to “looK” for the class.

The CustomDialect class was changed to reference these files:

Discussion

he connection.driver_class specification in SybaseASECoreDialect was the only “tricky” thing to “get right”. In the NHibernate “virgin” SysbaseASE15Dialect only specifies the “Driver” class name for the connection.driver_class

The NHibernate can “find” Nhibernate.Driver.SybaseAseClientDriver as it is contained within the NHibernate DLL. Using the custom classes it is necessary to specify the “full name” as the code is in separate assembly

API Versioning and Swagger

June 28, 2021

The Problem

API Versioning was added to a Microsoft C# Web API project .NET Core.

[ApiVersion("2.1")]
public class MyController: ApiController
{
}

The Swagger page for the API then did not list the API endpoints

The Solution

Simply add the [ApiController] attribute to the class

[ApiVersion("2.1")]
[ApiController]
public class MyController: ApiController
{
}

.NET Core WebAPI CORS

July 6, 2020

The Problem

How hard can it be to configure CORS in a .NET Core 3.1 WebAPI? The answer…quite hard.

The Microsoft documentation shows how to configure CORS and it should be straightforward. However, my experience and the exeperience of many others on StackOverflow have shown me that all is far from simple….Although the solution, when finally found was remarkably simple.

Code

CORS can be configured on the ConfigureServices method in Startup.cs with more or less:

services.AddCors(options =>
{
options.AddPolicy(name: "myCORSPolicy",
builder =>
{
    builder.WithOrigins(this.ApiConfiguration.CorsOrigins.ToArray());

     builder.AllowAnyMethod();
     builder.AllowAnyHeader();
     builder.AllowCredentials();
});

});

and in the Configure method

 app.UseCors("myCORSPolicy");

First Problem

So..I’m on an internal development network and I want to allow all origins (i.e. “*”) and AllowCredentials (as I want to use Active Directory).

Wrong!

The combination of .WithOrigins(“*”) and AllowCredentials is expressly forbidden and will generate a run-time exception.

Second Problem – Trailing Slashes

The .WithOrigins takes a “list” of origins i.e. URLs which can access your API. These must not have trailing slashes, e.g.

http://mydomain.com  - works

http://mydomain.com/ - CORS will not allow access from this origin

Microsoft do mention this in their documentation. however, it is far from clear and easily overlooked.

Category: .NET Core

The Problem

The Problem

The Solution

The Problem

The Solution

The Problem

Solution Attempt Number 1

Code

Errors

Discussion

Solution Attempt Number 2

Code

Errors

Discussion

The Real Solution

Code

Discussion

The Problem

The Solution

The Problem

Code

First Problem

Second Problem – Trailing Slashes