Configuration.md

Configuration

We use Microsoft.Extensions.Hosting for any configuration related work.

For more documentation on configuration, read the references listed at the bottom.

Configuring

The IConfiguration is populated using 3 layers of configuration files.

1. appsettings.json is the base layer. Use this to set default values.

2. appsettings.{environment}.json is the environment specific layer. Use this to set values that are specific to environments such as API clients, API keys, etc. You can customize the environments like you want. Check Environments.md for more info.

   Don't put production secrets directly in appsettings.production.json! Instead, use a placeholder token along with a powershell replace in the pipeline to inject secrets in your configuration files.

3. appsettings.override.json is an optional file that appears when you override a value from the application.

Check the AddAppSettings method from AppSettingsConfiguration.cs file to see how the 3 layers are setup.

Accessing

• The IConfiguration interface is registered as a service to simplify the process of resolving an application setting.

  // You can resolve the configuration in the constructor of a service using the IoC.
  public class MyService(IConfiguration configuration) { ... }
  
  // You can resolve the configuration from a view model using the IoC.
  var configuration = this.GetService<IConfiguration>();

• Custom properties can be added to the configuration. They can then be resolved using IConfiguration.

  Assuming this is the content of your appsettings.json.

  {
    "MySection": {
      "MyProperty1": "MyProperty1Value",
      "MyProperty2": {
        "MyProperty3": "MyProperty3Value"
      }
    }
  }

  There are multiple ways to resolve the properties.

  // You can resolve the properties using IConfiguration as a dictionary.
  var property1 = configuration["MySection:MyProperty1"];
  
  // You can resolve the properties using strongly-typed Options.
  var property1 = configuration.GetSection("MySection").Get<MyOptions>();
  
  public class MyOptions
  {
      public string MyProperty1 { get; set; }
  
      public MyOtherOptions MyProperty2 { get; set; }
  
      ...
  }

References

• Using IConfiguration