.NET and Pkl - Be Able for Thine Enemy

Pkl is a language from Apple for configuration management that advetises itself to be programmable, scalable, and safe. It can generate any static configuration format like json, yaml, or properties files. The configuration can adhere to a user-defined schema, so you can catch errors before deployment - this was the selling point for me because I have been burnt by misconfiguration in the past.

I have mostly been programming in dotnet these days. The most common format for managing configuration in dotnet application is json with appsettings.json, appsettings.Development.json etc. Is it be possible to use pkl for managing configuration in dotnet apps? The most obvious benefit would definitely be catching errors before any deployment.

Turns out, Apple does not officially support C# for Pkl. There is out-of-the-box support for Java, Kotlin, Swift, and Golang. I looked around and found a community-supported package

To add support for Pkl in your dotnet project, you’d need to add a reference to the NuGet Package PklCsharp

dotnet add package PklCsharp

If you’re using dotnet hosting extensions, then you’d also need to add a reference to the PklCSharp.Microsoft.Extensions.Configuration.

dotnet add PklCSharp.Microsoft.Extensions.Configuration

In your program setup, add a reference to the pkl configuration files like so:

builder.Configuration.AddPklModule(ModuleSource.FileSource(<Path to pkl file>));

and that’s it. You can now write the configuration using Pkl files. You can also set custom schema for your configuration, and then you can catch configuration errors during startup!