How to add more configuration files to a web application?

[paulomorgado]

Is there an extension point to load more configuration file when using WebApplication.CreateBuilder() and WebApplication.CreateBuilderSlim()?

Is the only option to clear all configuration and load it all again?

[martincostello]

JsonConfigurationExtensions.AddJsonFile()

For example:

var builder = WebApplication.CreateBuilder();
builder.Configuration.AddJsonFile("whatever.json");

[paulomorgado]

@martincostello, that overrides anything that was supposed to have been overridden by environment variables and command-line arguments.

Configuration is roughly loaded in this order:

1. appsettings.json
2. appsettings{Environment}.json
3. Environment variables
4. Command line arguments

Configuration files need to be loaded before 3 and 4.

[davidfowl]

You can mutate the list of sources, here's an example of inserting it first. 

var builder = WebApplication.CreateBuilder(args);

builder.Configuration.InsertBefore(c =>
{
    c.AddJsonFile("MyInitialSource.json", optional: true);
});

var app = builder.Build();

app.MapGet("/", () => "Hello World!");

app.Run();

public static class ConfigurationExtensions 
{
    public static ConfigurationManager InsertBefore(this ConfigurationManager config, Action<ConfigurationManager> action)
    {
        // Get all existing sources and make a copy
        var existing = config.Sources.ToArray();
        // Clear theses sources
        config.Sources.Clear();
        // Mutate configuration
        action(config);
        // Add the older sources back
        foreach (var s in existing)
        {
            config.Sources.Add(s);
        }
        return config;
    }
}

[paulomorgado]

You can mutate the list of sources, here's an example of inserting it first. 

var builder = WebApplication.CreateBuilder(args);

builder.Configuration.InsertBefore(c =>
{
    c.AddJsonFile("MyInitialSource.json", optional: true);
});

var app = builder.Build();

app.MapGet("/", () => "Hello World!");

app.Run();

public static class ConfigurationExtensions 
{
    public static ConfigurationManager InsertBefore(this ConfigurationManager config, Action<ConfigurationManager> action)
    {
        // Get all existing sources and make a copy
        var existing = config.Sources.ToArray();
        // Clear theses sources
        config.Sources.Clear();
        // Mutate configuration
        action(config);
        // Add the older sources back
        foreach (var s in existing)
        {
            config.Sources.Add(s);
        }
        return config;
    }
}

Thanks.

I was just considering explicitly clearing the Sources and loading it all again.

Since Sources is an IList<T> I might be able to just Insert them.