/// <summary>
/// Wrap policy
/// </summary>
/// <param name="key"></param>
/// <param name="duration"></param>
/// <returns></returns>
private AsyncPolicyWrap <string> GetPolicyWrap(string key, TimeSpan?duration)
{
PolicyRegistry registry = new PolicyRegistry
{
// https://github.com/App-vNext/Polly/wiki/Cache
{ key, Policy.CacheAsync <string>(
cacheProvider: _cache.AsAsyncCacheProvider <string>(),
ttlStrategy: new RelativeTtl(duration ?? DefaultTimeToLive),
//new ContextualTtl(), used with context[ContextualTtl.TimeSpanKey], define ttl in different calls
//new SlidingTtl(duration ?? DefaultTimeToLive), each time the cache item is touched, ttl extend.
//new ResultTtl(), used for vary ttl base on T model pass in
cacheKeyStrategy: (ctx) => ctx.OperationKey, //OperationKey is default cacheKey
onCacheGet: (ctx, cacheKey) => Console.WriteLine($"Get : {cacheKey}"),
onCacheMiss: (ctx, cacheKey) => Console.WriteLine($"Miss : {cacheKey}"),
onCachePut: (ctx, cacheKey) => Console.WriteLine($"Put : {cacheKey}"),
onCacheGetError: (ctx, str, ex) => throw ex,
onCachePutError: (ctx, str, ex) => throw ex) }
};
var asyncPolicy = registry.Get <IAsyncPolicy <string> >(key);
return(Policy
.Handle <IOException>()
.WaitAndRetryAsync(3, retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)))
.WrapAsync(asyncPolicy));
}