How to update values into appsetting.json?

Question

I am using the IOptions pattern as described in the official documentation.

This works fine when I am reading values from appsetting.json,

Answer 1

I hope that my scenario covers your intent, I wanted to override the appsettings.json values if there are environment variables passed to the app at startup.

I made use of the ConfigureOptions method that is available in dotnet core 2.1.

Here is the Model that is used for the JSON from appsettings.json

public class Integration
{
 public string FOO_API {get;set;}
}

For the services in the statup.cs:

var section = Configuration.GetSection ("integration");
            services.Configure (section);
            services.ConfigureOptions();

Here is the implemenation:

public class ConfigureIntegrationSettings : IConfigureOptions
    {
        public void Configure(Integration options)
        {
            if (!string.IsNullOrEmpty(Environment.GetEnvironmentVariable("FOO")))
                options.FOO_API = Environment.GetEnvironmentVariable("FOO_API");

        }
    }

so if there is no value set it falls back to the appsettings.json