ConnectionString is null when deploying Azure Function

Question

I've been working with functions with Azure, I've built a very simple Http Function locally by following the example linked here, the only difference is I've defined a User table instead of a Todo table

Everything works as expected locally, I'm able to post and get.

However, when deploying the function and trying to make a POST request I see the following within the logs:

Executed 'User' (Failed, Id=5df9dffe-eedf-4b11-aa10-54fda00992b0, Duration=1ms)System.ArgumentNullException : Value cannot be null. (Parameter 'connectionString')

I've checked the SQL Server to ensure it's accessible by other Azure Services just encase that was causing a problem, but I can confirm it's set to allow.

I have found this question, I've gone through the steps and checked against mine and I can confirm my Function App configuration does have the AzureWebJobsStorage connection string.

I'm not 100% sure why this would be happening due to my lack of knowledge of functions at the moment, have anyone else experience this? if so how did you resolve it?

Update

After further testing, it seems the error is coming from my Startup class,

class Startup : FunctionsStartup
{
    public override void Configure(IFunctionsHostBuilder builder)
    {
        string connectionString = Environment.GetEnvironmentVariable("SqlConnectionString");
        builder.Services.AddDbContext<ApplicationDbContext>(
            options => SqlServerDbContextOptionsExtensions.UseSqlServer(options, connectionString));
    }
}

Upon deployment, connectionString variable is null.... not sure why though.

question from:https://stackoverflow.com/questions/65649441/connectionstring-is-null-when-deploying-azure-function

Answer 1

Yes, you can not get it because you didn't set it in the configuration settings.