private void CheckItem1AsString(IExternalCache externalCache)
{
var item = (string)externalCache.Get("Item 1");
Assert.IsNotNull(item);
Thread.Sleep(2000);
item = (string)externalCache.Get("Item 1");
Assert.IsNull(item);
}
/// <summary>
/// Wraps a memory cache in front of an external cache (such as redis) to optimise multiple retrievals per machine.
/// Key space should be unique within app domain and external-cache database but consistent across nodes in a farm.
/// Creates a .net MemoryCache instance named "MemoryFrontedExternalCache_{keyspace}" (usually no configuration of
/// this is required).
/// </summary>
/// <param name="keyspace">Key space must be unique within app domain and external-cache database but consistent across nodes in a farm.</param>
/// <param name="externalCache">The external distributed/network cache to get/store values from/in.</param>
/// <param name="traceWriter">Optional trace writer for detailed diagnostics.</param>
public MemoryFrontedExternalCache(string keyspace, IExternalCache externalCache, ITraceWriter traceWriter = null)
{
_memoryCache = new MemoryCache($"{nameof(MemoryFrontedExternalCache)}_{keyspace}");
_externalCache = externalCache;
_traceWriter = traceWriter;
// external cache keys must be unique within an app domain but common across a farm of servers/services (thus includes keyspace but no guid)
_cacheKeyPrefixItem = $"{nameof(MemoryFrontedExternalCache)}:{keyspace}:Item:";
// retrieval locks need to be unique within an instance (as NamedLock has a static dictionary of named locks)
// as multiple of these caches could be setup within an app domain (such as in testing), we need a guid in the key
// to ensure each one is only creating named locks against itself.
_lockKeyPrefixExternalRetrieve = $"{nameof(MemoryFrontedExternalCache)}:{keyspace}:Retrieve:{Guid.NewGuid():N}:";
}
public CreationTimestampedCache(string keyspace, IExternalCache externalCache, ITraceWriter traceWriter = null)
{
_cache = new MemoryFrontedExternalCache(keyspace, externalCache, traceWriter);
}
public CountCharactersServiceNewImplementation(IExternalCache cache)
{
_cache = cache;
}