aws/aws-sdk-net

public async Task<string> FunctionHandler(S3Event evnt, ILambdaContext context)
        {
            var serviceCollection = new ServiceCollection();
            ConfigureServices(serviceCollection);

            // service provider 
            var serviceProvider = serviceCollection.BuildServiceProvider();

            // entry to run app 
            var service = serviceProvider.GetService<ApplicationService>();
            return await service.LocalFunctionHandler(evnt, context);
        }
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddSingleton<Logger>();
            services.AddSingleton<IAmazonS3>(s3 => new AmazonS3Client(Amazon.RegionEndpoint.USEast1));
            services.AddSingleton<IAmazonBatch>(batch => new AmazonBatchClient(Amazon.RegionEndpoint.USEast1));
            services.AddTransient<ApplicationService>();
        }