Amazon Elastic Beanstalk variables configuration provider implementation for Microsoft.Extensions.Configuration.

AmazonEBConfigurationProvider.cs

using Microsoft.Extensions.Configuration;
using Newtonsoft.Json.Linq;
using System.IO;
using System.Linq;

namespace SklLib.Configuration.Amazon
{
    public class AmazonEBConfigurationProvider : ConfigurationProvider
    {
        private const string ConfigurationFilename = @"C:\Program Files\Amazon\ElasticBeanstalk\config\containerconfiguration";

        public override void Load()
        {
            if (!File.Exists(ConfigurationFilename))
                return;

            string configJson;
            try
            {
                configJson = File.ReadAllText(ConfigurationFilename);
            }
            catch
            {
                return;
            }

            var config = JObject.Parse(configJson);
            var env = (JArray)config["iis"]["env"];

            if (env.Count == 0)
                return;

            foreach (var item in env.Select(i => (string)i))
            {
                int eqIndex = item.IndexOf('=');
                Data[item.Substring(0, eqIndex)] = item.Substring(eqIndex + 1);
            }
        }
    }
}

AmazonEBConfigurationSource.cs

using Microsoft.Extensions.Configuration;

namespace SklLib.Configuration.Amazon
{
    public class AmazonEBConfigurationSource : IConfigurationSource
    {
        public IConfigurationProvider Build(IConfigurationBuilder builder)
        {
            return new AmazonEBConfigurationProvider();
        }
    }
}

AmazonEBExtensions.cs

using Microsoft.Extensions.Configuration;

namespace SklLib.Configuration.Amazon
{
    public static class AmazonEBExtensions
    {
        public static IConfigurationBuilder AddAmazonElasticBeanstalk(this IConfigurationBuilder configurationBuilder)
        {
            configurationBuilder.Add(new AmazonEBConfigurationSource());
            return configurationBuilder;
        }
    }
}