Autofac | An addictive NET IoC container | Dependency Injection library

You can define on custom retry strategy on implementing the interface IExecutionStrategy. If you want reuse the default SQL Server retry strategy, you can derive from SqlServerRetryingExecutionStrategy on override the method ShouldRetryOn :

Looks like you've found a bug! I've filed an issue about it on your behalf. You can read more technical details about it there, but the short version is that over the years we've changed some Autofac internals to support .NET Core and this looks like something we've missed.

The workaround until this is fixed will be to register the middleware in reverse order, which isn't awesome because once the fix is applied you'll have to reverse them back. :(

Autofac isn't going to be the way here, go with the factory.

For performance reasons, Autofac needs to be able to cache registrations, one of the many reasons you can't remove things from the container. Hypothetically you could create a lifetime scope with the devices in it and dispose/recreate that every time the device list changes, but that's going to make your app unstable since anything resolved from that scope will also be disposed and recreated.

It's also possible, it sounds like, that the device list may change as some class logic is executing. You'll want the latest list at the time you need to work with the devices, which means querying at that point - just like you'd query data from a database as you need it rather than inject it as a dependency.

Just go with the factory.

azure app service

This is almost certainly due to multiple instances of your app running.

What would be the safest way to have the backgroundservice running only once, beside going through some data persist / check in DB?

An external "lease" is the safest approach. You can build one yourself using CosmosDb / Redis as a backend, or you can use a built-in approach by factoring your background service out of your web app into either an Azure WebJob or an Azure Function. Both of those services use leases automatically for timer-triggered jobs.

Are the apps published as Single File Applications? If so, the documentation have some pointers.

Looking at the fact that it's extracting 3rd-party libraries, I'm guessing this may be relevant:

Previously in .NET Core 3.0, when a user runs your single-file app, .NET Core host first extracts all files to a directory before running the application. .NET 5 improves this experience by directly running the code without the need to extract the files from the app.

And this explains the location:

If extraction is used the files are extracted to disk before the app starts:

• If environment variable DOTNET_BUNDLE_EXTRACT_BASE_DIR is set to a path, the files will be extracted to a directory under that path.
• Otherwise if running on Linux or MacOS, the files will be extracted to a directory under $HOME/.net.
• If running on Windows, the files will be extracted to a directory under %TEMP%/.net.

There's a bit to unpack here and, while I can kind of explain why things aren't working the way you want, the short answer is you're probably going to have to redesign how you're doing what you're doing. Which is likely not the answer you want, but... it's the answer.

To understand why, we need to ignore Autofac entirely for a moment and just look at the types you're working with.

You have an interface:

What you're trying to do is possible, but it's not a common thing and isn't something magic you'll get out of the box. You'll have to write code to implement it.

Before I get to that... from a future perspective, you might get help faster and more eyes on your question if your repro is far more minimal. The whole BusinessAction isn't really needed; the RequestHandler isn't needed... honestly, all you need to repro what you're doing is:

The service provider from IHost can be used to resolve main view model

Each DbContext can config their own entity

Let assume we have 10 entities for 3 DbContext, we can separate them out 2 entities for ADbContext, 5 for BDbContext and 3 for CDbContext. Manage the configuration like FK, between them wisely, otherwise, that would turn to be chaos. Here is how to doing this, using fluent API