Pulumi: How to update AppSettings of an AppFunction

How can I update the AppSettings of a FunctionApp resource in Pulumi?

Context:

After retrieving the connection string from a recently declared Service Bus Namespace resource, I now need to update the AppSettings property of a recently declared FunctionApp resource.

Resource Declaration:

var functionApp = appProfile.Items.Single(p => p.Key == "Name").Value;

return
    new FunctionApp(functionApp, new()
    {
        Name               = functionApp,
        Location           = resourceGroup.Location,
        ResourceGroupName  = resourceGroup.Name,
        AppServicePlanId   = plan.Id,
        StorageAccountName = storageAccount.Name,
        AppSettings        = new InputMap<string>() { appSettings },
        StorageAccountAccessKey = storageAccount.PrimaryAccessKey,
    });

Connection String:

I assume a connection string can only be realized after a resource has been provisioned in Azure.

var namespaceKeys =
    Output.Tuple(busNamespace.Name, authRule.Name)
          .Apply(async entries => await ServiceBus.ListNamespaceKeys.InvokeAsync(new ServiceBus.ListNamespaceKeysArgs
          {

              NamespaceName = entries.Item1,
              AuthorizationRuleName = entries.Item2,
              ResourceGroupName = resourceGroup.GetResourceName()
          }));

var connectionString = namespaceKeys.Apply(ns => ns.PrimaryConnectionString);

So how can I include the connection string, as an AppSetting to a FunctionApp resource, that is pending Service Bus Namespace creation?

I learned that I don't need to update the app settings of an Azure Function App. Instead, I need to rely on the type/utility, ServiceBus.ListNamespaceKeysArgs.

Example:

For a service bus connection string, the following example can be leveraged:

using Pulumi;
using Pulumi.AzureNative.Resources;
using ServiceBus = Pulumi.AzureNative.ServiceBus;

namespace IaC.MyApp.Client;

public static class ConnectionString
{
    public static Output<string> Get(ResourceGroup resourceGroup, ServiceBus.Namespace busNamespace, ServiceBus.NamespaceAuthorizationRule authRule)
    {
        var namespaceKeys =
            Output.Tuple(busNamespace.Name, authRule.Name)
                  .Apply(async entries => await ServiceBus.ListNamespaceKeys.InvokeAsync(new ServiceBus.ListNamespaceKeysArgs {

                      NamespaceName         = entries.Item1,
                      AuthorizationRuleName = entries.Item2,
                      ResourceGroupName     = resourceGroup.GetResourceName()
                  }));

        return namespaceKeys.Apply(ns => ns.PrimaryConnectionString);
    }
}

Client:

Here's the client code:

var connectionString = ConnectionString.Get(resourceGroup, busNamespace, authRule);

Prerequisites:

Note that a NamespaceAuthorizationRule needs to be declared as a prerequisite to getting the connection string of a service bus in Azure.

The following declaration is an example:

new NamespaceAuthorizationRule(ruleName, new NamespaceAuthorizationRuleArgs {

    AuthorizationRuleName = ruleName,
    NamespaceName     = busNamespace.Name,
    ResourceGroupName = resourceGroup.Name,
    Rights = new[] { AccessRights.Listen,
                     AccessRights.Send
                   }
});