How to modify IConfiguration natively injected in Azure Functions

Question

We need to add configuration providers to the native IConfiguration that is supplied to the Azure Functions natively. Currently we are completely re

Answer 1

A simpler solution would be to override the ConfigureAppConfiguration method in your FunctionStartup class (https://docs.microsoft.com/en-us/azure/azure-functions/functions-dotnet-dependency-injection#customizing-configuration-sources).

The following example takes the one provided in the documentation a step further by adding user secrets.

public override void ConfigureAppConfiguration(IFunctionsConfigurationBuilder builder)
{
    FunctionsHostBuilderContext context = builder.GetContext();

    builder.ConfigurationBuilder
        .SetBasePath(context.ApplicationRootPath)
        .AddJsonFile("appsettings.json", optional: true, reloadOnChange: false)
        .AddJsonFile($"appsettings.{context.EnvironmentName}.json", optional: true, reloadOnChange: false)
        .AddUserSecrets(Assembly.GetExecutingAssembly(), true, true)
        .AddEnvironmentVariables();
}

By default, configuration files such as appsettings.json are not automatically copied to the Azure Function output folder. Be sure to review the documentation (https://docs.microsoft.com/en-us/azure/azure-functions/functions-dotnet-dependency-injection#customizing-configuration-sources) for modifications to your .csproj file. Also note that due to the way the method appends the existing providers it is necessary to always end with .AddEnvironmentVariables().

A deeper discussion on configuration in an Azure Function can be found at Using ConfigurationBuilder in FunctionsStartup