Allow more control for middleware pipeline ordering

[gvkries]

Is your feature request related to a problem? Please describe.

When a feature has a dependency on two other features and must explicitly add a middleware in between these two dependencies, ordering cannot be achieved with ConfigureOrder alone without possibly changing the order related to other modules.

The ordering of startups currently only allows to have one or more dependencies ensuring startup occurs after those dependencies, or a global Order and ConfigureOrder property, which changes the order in relation to all other modules.

Describe the solution you'd like

It would be beneficial to explicitly set the order only in relation to other dependencies.

[Piedone]

Can you please explain why Order doesn't work? I think it should only be a problem if both dependencies have the same Order (like having the default 0). But If Dependency A has Order 10, and Dependency B 0, then if you set it to 5 in your module's Startup, it should register in between the two.

Related: #15173 (comment)

[gvkries]

Most of Orchards own modules have a default ordering of 0 and you cannot change that order from a module. Even when working with the Orchard source directly, you have to change the order of all concerning modules. Which then effects all other modules as well. Using feature dependencies also does not solve this, if your requirement is to have the module be loaded before your dependency. Additionally when changing the Order, any feature dependency will be ignored as well.

To summarize: For internal modules I guess Order can be enough, if everything is calculated very carefully. But at least for external modules (e.g. when using NuGet packages), you cannot achieve every ordering that might be required.

[Piedone]

Hmm. We'd then have three ways to configure this (module dependency, Order, middleware ordering) with different drawbacks.

I looked into why ASP.NET Core doesn't have anything for middleware dependencies/such ordering, but I couldn't find anything. I guess there's a reason, though.

[gvkries]

I looked into why ASP.NET Core doesn't have anything for middleware dependencies/such ordering, but I couldn't find anything. I guess there's a reason, though.

Yeah, in normal ASP.NET it's always explicitly ordered in the startup of the app. Only the modularity of Orchard brings this complexity with it 🤷‍♂️ And I don't have a simple solution yet.

[hishamco]

@gvkries As you said before most of the built-in OC modules have order 0, could you please give me an example when you set the order of your module is not enough?

[gvkries]

@gvkries As you said before most of the built-in OC modules have order 0, could you please give me an example when you set the order of your module is not enough?

See #15173 (comment) for a real world example, but the problem is not limited to this.

Any module with a specific order requirement in relation to two ore more other modules will have this problem. You cannot describe ordering without also changing the order of the core modules.

[hishamco]

You can set the order of newly added modules to run before or after any built-in module, let me check the PR that you refer to

[gvkries]

You can set the order of newly added modules to run before or after any built-in module, let me check the PR that you refer to

Yes, but you cannot insert in between two or more modules.