How to check Azure function is running on local environment? `RoleEnvironment` is not working in Azure Functions

Question

I have a condition in code where i need to check if current environment is not local.i have used !RoleEnvironment.IsEmulated, now this is not working in Azure

Answer 1

You can use an approach similar to what the actual runtime uses to identify whether it is running on Azure: https://github.com/Azure/azure-webjobs-sdk-script/blob/efb55da/src/WebJobs.Script/Config/ScriptSettingsManager.cs#L25

In this case, the runtime checks for the presence of an app setting named WEBSITE_INSTANCE_ID

Answer 2

Based on answer by Fabio Cavalcante, here is a working Azure function that checks the current running environment (local or hosted):

using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.Azure.WebJobs.Host;
using System;

namespace AzureFunctionTests
{
    public static class WhereAmIRunning
    {
        [FunctionName("whereamirunning")]
        public static async Task<HttpResponseMessage> Run([HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)]HttpRequestMessage req, TraceWriter log)
        {
            bool isLocal = string.IsNullOrEmpty(Environment.GetEnvironmentVariable("WEBSITE_INSTANCE_ID"));

            string response = isLocal ? "Function is running on local environment." : "Function is running on Azure.";

            return req.CreateResponse(HttpStatusCode.OK, response);
        }
    }
}

Answer 3

You can use the AZURE_FUNCTIONS_ENVIRONMENT environment variable, which is set automatically in local development:

Environment.GetEnvironmentVariable("AZURE_FUNCTIONS_ENVIRONMENT"); // set to "Development" locally

Note that when deployed/published (i.e. Azure), you'd need to set the environment variable yourself (e.g. function app settings in Azure).