Hi William,

I usually use an environment variable to toggle the server role:

 public class MyComposer : IComposer
 {
      private readonly string _serverRole;

      public Composer()
      {
           var serverRole = Environment.GetEnvironmentVariable("UMBRACO_SERVER_ROLE");

           if (serverRole.IsNullOrWhiteSpace() == false)
           {
                _serverRole = serverRole;
           }
      }

      public void Compose(IUmbracoBuilder builder)
      {
           // Explicitly set Server Role
           if (_serverRole.InvariantEquals("SchedulingPublisher"))
           {
                builder.SetServerRegistrar<SchedulingPublisherServerRoleAccessor>();
           }
           else if (_serverRole.InvariantEquals("Subscriber"))
           {
                builder.SetServerRegistrar<SubscriberServerRoleAccessor>();
           }
           else if (_serverRole.InvariantEquals("Single"))
           {
                builder.SetServerRegistrar<SingleServerRoleAccessor>();
           }
      }
 }

 public class SchedulingPublisherServerRoleAccessor : IServerRoleAccessor
 {
      public ServerRole CurrentServerRole => ServerRole.SchedulingPublisher;
 }

 public class SubscriberServerRoleAccessor : IServerRoleAccessor
 {
      public ServerRole CurrentServerRole => ServerRole.Subscriber;
 }

This class can be placed at the root of your project (alongside the appsettings.json files is fine).

The UMBRACO_SERVER_ROLE environment variable can then be set via the Web App's app settings in Azure, via the Configuration tab. (Set to SchedulingPublisher for the backoffice app, and Subscriber for the frontends)

Much easier than having 2 separate branches, as it removes the possibility of a merge accidentally changing the role to something else.

But if you do need to use 2 separate branches, then you can use the same code, but just remove the if statements and env variable code. e.g:

 public class MyComposer : IComposer
 {
      public void Compose(IUmbracoBuilder builder)
      {
           // Explicitly set Server Role as Scheduling Publisher
           builder.SetServerRegistrar<SchedulingPublisherServerRoleAccessor>();
      }
 }

 public class SchedulingPublisherServerRoleAccessor : IServerRoleAccessor
 {
      public ServerRole CurrentServerRole => ServerRole.SchedulingPublisher;
 }

Hope that helps!

Thank you Owain, that makes total sense to set the role in the Azure configuration as opposed to having 2 branches of code.

Apologies for my ignorance (I only understand the basics of how Umbraco works), but essentially I could create a file with solely the code above, place it in the root folder and it would set the roles - as long as I add the configuration in Azure?

What would the file name need to be called?

Would it need to be referenced anywhere else?

Presumably, we would always need at least 1 'Subscriber' Web App, in order for the site to work, e.g. we couldn't have 1 'SchedulingPublisher' Web App and then only turn on 'Subscriber' Web Apps as and when we needed the extra load?

... and the 2 types, e.g. 'SchedulingPublisher' and 'Subscriber' would need to be on different App Service Plans in order to get the benefit?

Thank you for your clear breakdown.

When we deploy the LoadBalancer.cs file with this code, it is providing 6 errors in the logs:

"C:\home\site\repository\PROJECTFOLDER\COMPANY.Web.csproj" (default target) (1:7) -> (CoreCompile target) -> C:\home\site\repository\PROJECTFOLDER\LoadBalancer.cs(1,28): error CS0246: The type or namespace name 'IComposer' could not be found (are you missing a using directive or an assembly reference?) [C:\home\site\repository\PROJECTFOLDER\COMPANY.Web.csproj] C:\home\site\repository\PROJECTFOLDER\LoadBalancer.cs(5,14): error CS1520: Method must have a return type [C:\home\site\repository\PROJECTFOLDER\COMPANY.Web.csproj] C:\home\site\repository\PROJECTFOLDER\LoadBalancer.cs(33,55): error CS0246: The type or namespace name 'IServerRoleAccessor' could not be found (are you missing a using directive or an assembly reference?) [C:\home\site\repository\PROJECTFOLDER\COMPANY.Web.csproj] C:\home\site\repository\PROJECTFOLDER\LoadBalancer.cs(35,14): error CS0246: The type or namespace name 'ServerRole' could not be found (are you missing a using directive or an assembly reference?) [C:\home\site\repository\PROJECTFOLDER\COMPANY.Web.csproj] C:\home\site\repository\PROJECTFOLDER\LoadBalancer.cs(38,46): error CS0246: The type or namespace name 'IServerRoleAccessor' could not be found (are you missing a using directive or an assembly reference?) [C:\home\site\repository\PROJECTFOLDER\COMPANY.Web.csproj] C:\home\site\repository\PROJECTFOLDER\LoadBalancer.cs(40,14): error CS0246: The type or namespace name 'ServerRole' could not be found (are you missing a using directive or an assembly reference?) [C:\home\site\repository\PROJECTFOLDER\COMPANY.Web.csproj]

Hi William,

You'll need to add the following usings, to the top of the LoadBalancer.cs file, to load the required assemblies:

using Umbraco.Cms.Core.Composing;
using Umbraco.Cms.Core.Sync;
using Umbraco.Cms.Infrastructure.DependencyInjection;

I believe these are all you'll need, but your IDE should tell you if you need any others :)

Thanks Owain. I have added these to the top of the 'LoadBalancer.cs' file, but it is still giving a deployment error.

I am not sure if it is the done thing on the forum (so apologies if not) but could I pay for your time, to jump on a call and see if you would be able to point me in the right direction of where it is failing?

We managed to fix the deployment issues.

Just 2 other questions if you are able to clarify:

1 - Typically should the base specification of the server have more compute power on the SchedulingPublisher or the Subscriber?

2 - If we have a custom domain linking to the Azure Web App, would we setup the Subscriber to point to the frontend domain, e.g. www.SITE.com and the SchedulingPublisher to a different domain - or what is standard practice for this?

Thank you. That is really helpful!

From further reading, it is recommended that for the Lucene/Examine configuration:

1. The single instance Backoffice Administrative Web App should be set to use SyncedTempFileSystemDirectoryFactory.

2. The multi-instance Scalable Public Web App should be set to use TempFileSystemDirectoryFactory.

Source: https://docs.umbraco.com/umbraco-cms/fundamentals/setup/server-setup/load-balancing/azure-web-apps

How do you configure that in the appsettings.json to avoid having to have 2 branches of code?

Thank you so much.

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