.NET Configuration in Depth

Chris Ayers

Chris Ayers

Senior Customer Engineer
Microsoft

Twitter: @Chris_L_Ayers
Mastodon: @Chrisayers@hachyderm.io
LinkedIn: - chris-l-ayers
Blog: https://chris-ayers.com/
GitHub: Codebytes

Agenda

  • What is configuration?
  • How does .NET Framework handle configuration?
  • How does .NET and ASP.NET handle configuration?
  • Configuration Providers
  • Configuration Binding
  • The Options Pattern
  • Questions?

What is Configuration?

Settings

  • Retry Times
  • Queue Length

Feature Flags

  • Per User
  • Percentage

Secrets

  • Connection Strings
  • App Registration

When is configuration applied?

Compile Time

Run Time

.NET Framework Configuration

Web.Config

  • Limited to Key-Value string pairs
  • Accessed through a static ConfigurationManager Class
  • Dependency Injection was not provided out of the box
  • Transformation through difficult syntax
    • Slow Cheetah
  • Hard to unit test
  • Easy to leak secrets

XML, Static Classes, and Parsing

.NET 6/ASP.NET Configuration

Configuration Providers

center

Order Matters

center

Keys are flattened

Binding a Section

Out of the Box

Console

  • No Configuration

ASP.NET

  • JSON
    • appsettings.json
    • appsettings.{Environment}.json
  • Environment Variables
  • Command Line Variables
  • User Secrets

Configuration Providers

File-based

  • JSON
  • XML
  • INI
  • Key-per-file

Others

  • Environment variables
  • Command-line
  • In-Memory
  • User Secrets
  • Azure Key Vault
  • Azure App Configuration

Json Provider

Xml Provider

Environment Variables

Command Line Variables

Key-per-file

In Memory

DEMOS

The Options Pattern

The Interface Segregation Principle (ISP) or Encapsulation: Scenarios (classes) that depend on configuration settings depend only on the configuration settings that they use.

Separation of Concerns : Settings for different parts of the app aren't dependent or coupled to one another.

Types of IOptions

Singleton Reloading Support Named Option Support
IOptions
 Yes No No
IOptionsSnapshot
 No Yes Yes
IOptionsMonitor
 Yes Yes Yes

DEMOS

Questions?

Contact

Twitter: @Chris_L_Ayers
Mastodon: @Chrisayers@hachyderm.io
LinkedIn: - chris-l-ayers
Blog: https://chris-ayers.com/
GitHub: Codebytes