Azure Blob storage

Xperience by Kentico supports file system providers that allow you to map parts of the file system to Microsoft Azure Blob Storage. You can use Blob storage when:

• deploying Xperience projects to the SaaS environment
• deploying self-managed projects
• you wish to store parts of the application file system (e.g., media library files) in a shared storage

Blob storage is particularly suitable for storing content item assets, media library files and all other unmanaged binary files referenced by the Xperience application. Some application deployment environments, like Azure Web Apps for example, do not guarantee a persistent filesystem for files created outside of the original deployment package. Therefore, if Azure needs to recycle the application due to rolling infrastructure updates or unexpected outages, all but the image with the original deployment is lost. Blob storage does not suffer from these limitations, as the infrastructure ensures redundancy in case of an outage.

Follow the instructions on this page to create Azure Blob storage providers for:

• projects for deployment to the SaaS environment
• self-managed Xperience projects

Media library files in Azure Blob storage

Media library files stored in Azure Blob storage have the following limitations:

• Storing a large number (thousands) of media library files in a single media library can significantly affect the performance and user experience of the Media libraries application.
  • We recommend structuring media library files into multiple media libraries and storing at most 100 files in a single media library folder.
• Mapping subfolders of media libraries is not supported. You can map either the directory containing the media libraries (~/assets/media), or individual media libraries (~/assets/media/<MediaLibraryName>).
• The system’s automatic clearing of files from the server-side cache does not work for files stored in an external storage. If you modify a media file, the website may still display the old version until the cache expires (unless you manually clear the application’s cache). See also: File caching.

Store files in managed Azure Blob storage

When developing an Xperience application that you want to deploy to the SaaS environment, you need to create an Azure Blob storage provider (AzureStorageProvider) for folders with external application files and media library files that you want to deploy with your application.

Azure Blob storage is used when deploying to the SaaS environment, as storing persistent data alongside Xperience application binaries deployed in Azure App Service is not recommended.

Default managed Azure Blob storage configuration

Xperience provides Azure Blob storage with the required accounts as part of every subscription. Projects created with the --cloud parameter contain the StorageInitializationModule.cs file with a sample storage initialization module and the Export-DeploymentPackage.ps1 deployment script.

The default configuration maps:

• ~/assets (content item assets and media libraries) and ~/BizFormFiles (files uploaded via the Upload file form component) project folders to an Azure Blob storage provider for the Qa, Uat, and Production environments. The default Azure Blob storage container name is default.
  • Use Azure Blob storage containers to categorize files.
• ~/assets/media (media libraries) project folder to a local storage provider configured for the development environment. The media libraries are stored in the ~/$StorageAssets/default/assets/media folder, and a container named default, but accessed under the ~/assets/media path in your application.
  • Using local storage providers for development is a good practice, as it is not recommended to use production containers during development.

The default configuration ensures that when your application accesses the ~/assets/media folder, the mapping automatically forwards the request to the ~$StorageAssets/default/assets/media folder during development. When you deploy the application to the SaaS environment, your application stores the folders in the Azure Blob storage container named default. You can use multiple containers to store files.

The configuration can be further customized – see Map folders to a managed Azure Blob storage.

Map folders to a managed Azure Blob storage

To use a different configuration (a different container name or multiple containers for multiple folders), create, configure, and map Azure Blob storage providers and local file system providers for each folder:

1. Get a basic understanding of Azure Blob storage containers.
   • Use container names conforming to the naming requirements in Container names.
   • Use folder structure inside containers and file name requirements conforming to Naming and Referencing Containers, Blobs, and Metadata.
2. Edit the module in StorageInitializationModule.cs.
3. Get familiar with the module code and modify it to suit your application:

   1. Modify the MapAzureStoragePath method to map a directory to a specific Azure Blob storage provider:

      • Use the path method argument to set the folder you want to map to an Azure Blob storage provider, where ~ is your project root folder.

      • Set the PublicExternalFolderObject provider property to true, if you want the files from a container to be publicly accessible.

      • Use the container_name method argument to set the target Azure Blob storage container. Use a separate folder for each folder you want to deploy to a separate Azure Blob storage container.

        Containers do not need to have an existing folder in the storage assets root folder, but need to have a valid mapping in your application – Xperience automatically ensures that the folder structure gets created in Azure Blob storage when your application tries to access those folders when deployed to Azure Blob storage.

        Containers in deployment environments are isolated. You can map folders in different environments to containers with identical names.

        Mapping a folder to an Azure Blob storage provider

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          private void MapAzureStoragePath(string path, string containerName)
          {
              // Creates a new StorageProvider instance for Azure Blob storage
              var provider = AzureStorageProvider.Create();
              // Specifies the target container
              provider.CustomRootPath = containerName;
              provider.PublicExternalFolderObject = false;
        
              StorageHelper.MapStoragePath(path, provider);
          }
        
          

   2. Modify the MapLocalStoragePath method to create a local storage provider for storage assets. Use a separate folder for each folder you want to deploy to a separate Azure Blob storage container under ~/$StorageAssets/<container_name>:

      • Use the path method argument to set the folder you want to map to a local storage provider, where ~ is the root folder of your project,

      • Use the container_name method argument to set the target Azure Blob storage container. Use a separate folder for each folder you want to deploy to a separate Azure Blob storage container.

        Mapping a folder to a local storage provider

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          private void MapLocalStoragePath(string path, string containerName)
          {
              // Creates a new StorageProvider instance for local storage
              var provider = StorageProvider.CreateFileSystemStorageProvider();
              // A local path where to map the folder
              provider.CustomRootPath = $"{LOCAL_STORAGE_ASSETS_DIRECTORY_NAME}/{containerName}";
        
              StorageHelper.MapStoragePath(path, provider);
          }
        
          

        You can use a different root folder than $StorageAssets to store the local binary files. Change the $StorageAssetsFolderName variable in Export-DeploymentPackage.ps1 script and the LOCAL_STORAGE_ASSETS_DIRECTORY_NAME variable in StorageInitializationModule.cs.

   3. Modify the OnInit() method to map the folder path either to the Azure Blob storage provider or to a local storage provider, depending on the current environment.

      Mapping project folders to managed Azure storage

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       // Changed from "$StorageAssets". "Export-DeploymentPackage.ps1" needs to reflect this.
       private const string LOCAL_STORAGE_ASSETS_DIRECTORY_NAME = "CustomStorageAssetsFolder";
       private const string CONTAINER_NAME_LIBRARIES = "media-libraries-container";
       private const string CONTAINER_NAME_CONTENT_ITEM_ASSETS = "content-item-assets-container";
       private const string CONTAINER_NAME_FORM_FILES = "biz-form-files-container";
       private const string CONTAINER_NAME_DOCUMENTS = "documents-container";
      
       // Initialization code executed on application startup
       protected override void OnInit()
       {
           base.OnInit();
           //
           // NOTE: The "~" gets resolved into the project root
           // NOTE: The "documents" folder is an example folder with arbitrary document files
           //
      
           // Mapping for SaaS deployment environments:
           // -- media libraries to "media-libraries-container"
           // -- content item assets to "content-item-assets-container"
           // -- form files to "biz-form-files-container"
           // -- "documents" folder to "documents-container"
           //
           if (Environment.IsQa() || Environment.IsUat() || Environment.IsProduction())
           {
               MapAzureStoragePath("~/assets/media", CONTAINER_NAME_LIBRARIES);
               MapAzureStoragePath("~/assets/contentitems", CONTAINER_NAME_CONTENT_ITEM_ASSETS); 
               MapAzureStoragePath("~/BizFormFiles", CONTAINER_NAME_FORM_FILES);
               MapAzureStoragePath("~/assets/documents", CONTAINER_NAME_DOCUMENTS);
      
           } 
      
           // Mapping for the local development environment, under the "~/CustomStorageAssetsFolder/" folder:
           // -- media libraries to the "media-libraries-container" folder
           // -- "documents" folder to the "documents-container" folder
           // NOTE: The "~/CustomStorageAssetsFolder/" folder is exported into the deployment package.
           else    
           {
               MapLocalStoragePath("~/assets/media", CONTAINER_NAME_LIBRARIES);
               MapLocalStoragePath("~/assets/documents", CONTAINER_NAME_DOCUMENTS);
           }
       }
      
       

4. Rebuild the solution.
5. Create and deploy the deployment package.

The binary files are now deployed according to the defined configuration and environment – either to Azure Blob storage or to local storage.

Store files in self-managed Azure Blob storage

To map parts of the file system of self-managed deployments to the Azure Blob storage:

1. Follow these recommendations:

   1. Use separate Azure Blob storage containers for each deployment environment for the same project (for example, production and testing environments). Such environments often contain identically named files that overwrite each other. To avoid collisions, use the CustomRootPath property to map folders for each environment to a different container.
   2. Use HTTPS to connect to Azure Blob Storage accounts (this behavior can be enabled via the Security transfer required setting available in the Azure portal). Xperience is by default configured to use HTTPS with Azure Blob Storage.

      • If you need to use HTTP (for example because of storage accounts supporting only unencrypted (HTTP) connections), include the CMSAzureBlobEndPoint configuration key in your application’s configuration file. Set the value of the key to the full endpoint URL of the external storage account and explicitly specify the HTTP protocol:

        appsettings.json

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          {
          ...
        
              "CMSAzureBlobEndPoint": "http://_StorageAccountName_.blob.core.windows.net"
          }
        
          

2. Specify the storage account name and primary access key in your application configuration file (appsettings.json by default).

   1. Open the Azure Management Portal.

   2. Open Storage accounts.

   3. Select your storage.

   4. Switch to the Access keys tab.

   5. Use the Storage account name and one of the provided access key values.

      appsettings.json

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       {
       ...
      
           "CMSAzureAccountName": "StorageAccountName",
           "CMSAzureSharedKey": "PrimaryAccessKey"
       }
      
       

3. Open the Xperience project in Visual Studio.

4. Add a custom Class Library project and add the Kentico.Xperience.AzureStorage NuGet package as a dependency.

5. Create a custom module class in the created library.

6. Override the module’s OnInit method and for each folder that you want to store in the blob storage:

   1. Create a new instance of the Azure storage provider.

   2. (Optional) Specify the target container using the CustomRootPath property of the provider.

   3. (Optional) You can specify whether you want the container to be publicly accessible using the PublicExternalFolderObject property of the provider. True means the container is publicly accessible.

   4. Map the folder to the provider:

      As some deployment environments don’t provide a persistent file system, we recommend mapping the following project folders to prevent a possible loss of files due to redeployment, swapping of slots, etc.:

      • ~/assets/ – contains content item assets and media libraries
      • ~/BizFormFiles/ – contains files uploaded from users using the Upload file form component
      Mapping assets and form files to self-managed Azure storage

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       /* The following code snippet demonstrates the recommended mappings 
       for the **~/assets/** and **~/BizFormFiles/** folders mentioned 
       in the note above. You can use the same approach to also map 
       other folders from your project's file system.*/
      
       using CMS;
       using CMS.DataEngine;
       using CMS.IO;
      
       using Kentico.Xperience.AzureStorage;
      
       // Registers the custom module into the system
       [assembly: RegisterModule(typeof(CustomInitializationModule))]
      
       public class CustomInitializationModule : Module
       {
           // Module class constructor, the system registers the module under the name "CustomInit"
           public CustomInitializationModule()
               : base("CustomInit")
           {
           }
      
           // Contains initialization code that is executed when the application starts
           protected override void OnInit()
           {
               base.OnInit();
      
               // Creates new StorageProvider instances for Azure Blob storage
               var assetsProvider = AzureStorageProvider.Create();
               var formFilesProvider = AzureStorageProvider.Create();
      
               // Specifies the target containers, the providers ensure their existence in the storage account
               assetsProvider.CustomRootPath = "myassetscontainer";
               formFilesProvider.CustomRootPath = "myformfilescontainer";
      
               // Makes the 'myassetscontainer' container publicly accessible
               assetsProvider.PublicExternalFolderObject = true;
      
               // Makes the 'myformfilescontainer' container not publicly accessible
               formFilesProvider.PublicExternalFolderObject = false;
      
               // Maps the local directories to the storage providers
               StorageHelper.MapStoragePath("~/assets", assetsProvider);
               StorageHelper.MapStoragePath("~/BizFormFiles", formFilesProvider);            
           }
       }
      
       

7. (Optional) Set Optional application settings for Azure storage.

The application deployed in the Azure instance now stores files from the ~/assets and ~/BizFormFiles/ project folders in the myassetscontainer and myformfilescontainer Azure Blob storage containers.

Optional application settings for Azure storage

"CMSAzureTempPath": "C:\\AzureTemp"

 "CMSAzureCachePath": "C:\\AzureCache"

"CMSAzureBlobEndPoint": "http://127.0.0.1:10000/devaccount"

 "CMSAzurePublicContainer": "true"

"CMSDownloadBlobTimeout": "5"