Read Environment Variables in .NET Azure Functions

.NET Azure Functions can consume environment variables directly as any other .NET applications using System.Environment class. 

Code snippet

The following code snippet reads an environment variable named DefaultConnection. 

    public class Program
    {
        public static void Main()
        {
            var dbConnString = Environment.GetEnvironmentVariable("DefaultConnection");
        }
    }

The value of the variable can be stored in your system level environment variables or in development environment, it can be stored in local.settings.json file.

{
  "IsEncrypted": false,
  "Values": {
    "DefaultConnection": "Server=.;Database=mydb;Trusted_Connection=True;MultipleActiveResultSets=true",
    "AzureWebJobsStorage": "UseDevelopmentStorage=true",
    "FUNCTIONS_WORKER_RUNTIME": "dotnet-isolated"
  }
}

In Azure production environment, the variables can be configured in the portal or via CLI tools or other SDKs: