Use Redis Cache with Orchard Core

[miguelisidoro]

Hello,

I have a big solution that is using Orchard core as its backend and for now it is not running Distributed cache.
I would like to use Redis Cache as distributed cache. We are about to have 2 Azure App Service instances in our deployment (horizontal scaling) and a distributed cache system is necessary.

Is it possible to provide a full step by step guide on how to configure Redis Cache in a Orchard Core based solution?
We would like to configure all the settings necessary in Orchard Core by code if possible.

I have Googled, searched the Orchard Core official docs and searched the issues and discussions and couldn't find a detailed solution.
Can you help?

Thanks

[Piedone]

While docs on Redis are indeed sparse, the gist of it is this:

1. Configure the Redis settings, see here. This can be done in any of the configuration options, just the sample is in an appsettings file.
2. Enable all Redis features from the admin (or else). Though in Azure you don't necessarily need Redis DataProtection, since for that you can use the Blob Storage-using one too: https://docs.orchardcore.net/en/latest/reference/modules/DataProtection.Azure/.

[miguelisidoro]

@Piedone thanks for the reply.

About 2), is it enough to enable all Redis features on the default tenant and all other tenants will inherit Redis settings from the default tenant?

Thanks

[Piedone]

You'll need to enable it on all tenants. You don't need to do that one by one though, but like this too from your web app's Program:

builder.Services
    .AddOrchardCms()
    // Need to list all their dependencies too.
    .AddTenantFeatures("OrchardCore.Redis", "OrchardCore.Redis.Cache");

[miguelisidoro]

@Piedone thanks.

1 - When you say Program, do you mean the Startup?
2 - Any other feature we should enable besides OrchardCore.Redis.Cache?

I have in the admin the following features:

If yes, can you send the features names we should reference in the code?

Thanks

[Piedone]

The error indicates that your configuration is not applied. I guess either your app is not running with environment settings called "development" (I think casing matters here, shouldn't it be "Development"?), or what you have in your appsettings is incorrect. Such configuration should be below an "OrchardCore" property, see https://github.com/OrchardCMS/OrchardCore/blob/dc0d4fc4f291a2eba383b4c3e21a6da3b647ab7d/src/OrchardCore.Cms.Web/appsettings.json

[miguelisidoro]

@Piedone thanks. In fact, after changing the configuration to be below an "OrchardCore" property, the error disappears.

After running the web application, I get the following in my Redis container.

1 - Is this the expected content? If yes, does this mean that Redis is properly configured and the configuration is complete?
Our development tenant is called "Default", reason I assume that all keys in Redis Cache begin with "Default". Orchard Core prefixes all keys with the tenant name which allows multitenancy.

2 - Another question: where does Orchard Core caches shell settings? We activated Redis cache and there is nothing there and I assume that Orchard Core does not retrieve shell settings from blob storage or database in every request.

Thanks

[Piedone]

1. Looks good, yes.
2. It basically caches them here, in a field.

[miguelisidoro]

@Piedone thanks. Is it possible for us to cache shell settings in Redis? Something that we can put on Startup that will cache shell settings in Redis? Caching shell settings in Redis would allow caching to be distributed which is important if we have more than one instance in our case in Azure. Without caching shell settings in Redis, and if we have more than one instance, if we for example create a new tenant, the new tenant is not recognised in all instances.

[Piedone]

I think this is handled somehow; I might actually be wrong on why there are no repeated shell settings queries (a tenant, once running, will keep its ShellSettings object in memory until it's, even remotely via Redis, restarted, but there can be queries for fetching the shell configuration document for other tenants). But I'll need to leave the rest of this as an exercise for the reader :).