[PM-6177] Persistent distributed cache using Cosmos (#3772)

* cosmos distributed cache

* rename container to default

src/Api/Utilities/ServiceCollectionExtensions.cs

@@ -90,9 +90,9 @@ public static class ServiceCollectionExtensions
                 builder.AddSqlServer(globalSettings.SqlServer.ConnectionString);
             }
 
-            if (CoreHelpers.SettingHasValue(globalSettings.Redis.ConnectionString))
+            if (CoreHelpers.SettingHasValue(globalSettings.DistributedCache?.Redis?.ConnectionString))
             {
-                builder.AddRedis(globalSettings.Redis.ConnectionString);
+                builder.AddRedis(globalSettings.DistributedCache.Redis.ConnectionString);
             }
 
             if (CoreHelpers.SettingHasValue(globalSettings.Storage.ConnectionString))

src/Core/Core.csproj

@@ -38,6 +38,7 @@
     <PackageReference Include="Microsoft.Azure.Cosmos.Table" Version="1.0.8" />
     <PackageReference Include="Microsoft.Azure.NotificationHubs" Version="4.1.0" />
     <PackageReference Include="Microsoft.Data.SqlClient" Version="5.1.5" />
+    <PackageReference Include="Microsoft.Extensions.Caching.Cosmos" Version="1.6.0" />
     <PackageReference Include="Microsoft.Extensions.Configuration.EnvironmentVariables" Version="8.0.0" />
     <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" Version="8.0.0" />
     <PackageReference Include="Microsoft.Extensions.Identity.Stores" Version="6.0.25" />

src/Core/Settings/GlobalSettings.cs

@@ -55,7 +55,7 @@ public class GlobalSettings : IGlobalSettings
     public virtual MailSettings Mail { get; set; } = new MailSettings();
     public virtual IConnectionStringSettings Storage { get; set; } = new ConnectionStringSettings();
     public virtual ConnectionStringSettings Events { get; set; } = new ConnectionStringSettings();
-    public virtual IConnectionStringSettings Redis { get; set; } = new ConnectionStringSettings();
+    public virtual DistributedCacheSettings DistributedCache { get; set; } = new DistributedCacheSettings();
     public virtual NotificationsSettings Notifications { get; set; } = new NotificationsSettings();
     public virtual IFileStorageSettings Attachment { get; set; }
     public virtual FileStorageSettings Send { get; set; }
@@ -550,4 +550,10 @@ public class GlobalSettings : IGlobalSettings
         public string FlagDataFilePath { get; set; } = "flags.json";
         public Dictionary<string, string> FlagValues { get; set; } = new Dictionary<string, string>();
     }
+
+    public class DistributedCacheSettings
+    {
+        public virtual IConnectionStringSettings Redis { get; set; } = new ConnectionStringSettings();
+        public virtual IConnectionStringSettings Cosmos { get; set; } = new ConnectionStringSettings();
+    }
 }

src/SharedWeb/Utilities/ServiceCollectionExtensions.cs

@@ -48,6 +48,8 @@ using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.HttpOverrides;
 using Microsoft.AspNetCore.Identity;
 using Microsoft.AspNetCore.Mvc.Localization;
+using Microsoft.Azure.Cosmos.Fluent;
+using Microsoft.Extensions.Caching.Cosmos;
 using Microsoft.Extensions.Caching.Distributed;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
@@ -693,17 +695,34 @@ public static class ServiceCollectionExtensions
         this IServiceCollection services,
         GlobalSettings globalSettings)
     {
-        if (globalSettings.SelfHosted || string.IsNullOrEmpty(globalSettings.Redis.ConnectionString))
+        if (!string.IsNullOrEmpty(globalSettings.DistributedCache?.Redis?.ConnectionString))
         {
-            services.AddDistributedMemoryCache();
-            return;
-        }
-
             services.AddStackExchangeRedisCache(options =>
             {
-            options.Configuration = globalSettings.Redis.ConnectionString;
+                options.Configuration = globalSettings.DistributedCache.Redis.ConnectionString;
             });
         }
+        else
+        {
+            services.AddDistributedMemoryCache();
+        }
+
+        if (!string.IsNullOrEmpty(globalSettings.DistributedCache?.Cosmos?.ConnectionString))
+        {
+            services.AddKeyedSingleton<IDistributedCache>("persistent", (s, _) =>
+                new CosmosCache(new CosmosCacheOptions
+                {
+                    DatabaseName = "cache",
+                    ContainerName = "default",
+                    CreateIfNotExists = false,
+                    ClientBuilder = new CosmosClientBuilder(globalSettings.DistributedCache?.Cosmos?.ConnectionString)
+                }));
+        }
+        else
+        {
+            services.AddKeyedSingleton<IDistributedCache, MemoryDistributedCache>("persistent");
+        }
+    }
 
     public static IServiceCollection AddOptionality(this IServiceCollection services)
     {