How to: Create a DataCache Object in RoleEntryPoint Methods for Azure Managed Cache Service

Managed Cache Service settings in the web.config file are not automatically available from in the context of the RoleEntryPoint class (typically defined in the WebRole.cs file). When you attempt to create a DataCache object in the RoleEntryPoint class methods, the following error occurs:

{"ErrorCode<ERRCA0021>:SubStatus<ES0001>:Server collection cannot be empty."}

This happens because the dataCacheClient settings in the web.config file are not automatically being applied to the new DataCache client object. Specifically, the attributes of the autoDiscover element are unavailable, so the DataCache object is unable to target the role that hosts caching.

In this scenario, you must programmatically configure a DataCacheFactoryConfiguration object, which accesses the settings in the web.config file directly.

How to Programmatically Configure a Cache Client

1. Create a DataCacheFactoryConfiguration object.

   DataCacheFactoryConfiguration config = new DataCacheFactoryConfiguration();
   

2. Set the AutoDiscoveryProperty to a new DataCacheAutoDiscoverProperty object. This property is used to connect to the cache. Specify true to enable automatic discovery. Also specify the cache endpoint.

   config.AutoDiscoverProperty = new DataCacheAutoDiscoverProperty(true, "mycache.cache.windows.net");
   

3. Set the config.SecurityProperties property to a new DataCacheSecurity instance and specify the access key for the cache and whether you want SSL enabled for communication between the cache and clients.

   config.SecurityProperties = new DataCacheSecurity("[Replace with Access Key]", false);
   

   Note

   For more information, see Securing Communications between Cache Clients and the Cache.

4. Set any other properties on the DataCacheFactoryConfiguration object that control the behavior of the cache client.

5. Create a DataCacheFactory object, passing the DataCacheFactoryConfiguration object in the constructor.

   DataCacheFactory factory = new DataCacheFactory(config);
   

6. Call the DataCacheFactory.GetCache method to return the DataCache object for the target named cache.

   DataCache cache = factory.GetCache("default");
   

Example

// Create a DataCacheFactoryConfiguration object
DataCacheFactoryConfiguration config = new DataCacheFactoryConfiguration();

// Enable the AutoDiscoveryProperty (and any other required configuration settings):
config.AutoDiscoverProperty = 
    new DataCacheAutoDiscoverProperty(true, "mycache.cache.windows.net");

// Configure the access key and sslEnabled setting.
config.SecurityProperties = new DataCacheSecurity("[Replace with Access Key]", false);

// Create a DataCacheFactory object with the configuration settings:
DataCacheFactory factory = new DataCacheFactory(config);

// Use the factory to create a DataCache client for the "default" cache:
DataCache cache = factory.GetCache("default");