public static async Task <ITokenBucket> GetTokenBucketAsync(CustomerThrottle customerThrottle)
{
return(await TokenBuckets.BucketWithFixedIntervalRefillStrategy(
capacity : (long)customerThrottle.MaximumRequestsPerSecond,
refillTokens : (long)customerThrottle.MaximumRequestsPerSecond,
period : oneSecond).ConfigureAwait(false));
}
private async Task <ITokenBucket> CreateAndStoreTokenBucketContext(CustomerThrottle customerThrottle)
{
object objNewTokenBucket = await TokenBucketFactory.GetTokenBucketAsync(customerThrottle).ConfigureAwait(false);
CustomerThrottleContext newThrottleContext = CustomerThrottleContext.Create(
customerThrottle: customerThrottle,
tokenBucket: objNewTokenBucket);
contextDict.AddOrUpdate(customerThrottle.CustomerIdentityKey, newThrottleContext,
updateValueFactory: (factoryKey, factoryValue) =>
{
return(newThrottleContext);
});
return((ITokenBucket)objNewTokenBucket);
}
/// <summary>
/// Executes the delegate function on a throttled basis.
///
/// When this overload is called and no CancellationToken was passed at instance construction,
/// then the internal cancellation logic will use the CancellationToken passed to this method, and the same CancellationToken will be passed to the delegate.
/// When this overload is called and a CancellationToken was passed at instance construction,
/// then the internal cancellation logic will use the instance CancellationToken, and the CancellationToken passed to this overload will be passed to the delegate.
/// </summary>
/// <param name="customerThrottle">Determines which throttle-rate to use. If you pass a customerThrottle with an ID that hasn't been seen previously by the instance,
/// then a new underlying TokenBucket is created. If you pass a customerThrottle with an ID that has been seen previously by the instance, then you'll get the
/// underlying TokenBucket already associated with that ID.
/// If you want to change the throttling rate associated with a particular ID, just pass in a new customerThrottle object with the new maximumRequestsPerSecond property
/// value and the same ID.</param>
/// <param name="request">The request object (of type TRequest) to pass to the delegate.</param>
/// <param name="cancellationToken"></param>
/// <returns></returns>
public async Task <TResponse> ExecuteThrottledAsync(CustomerThrottle customerThrottle, TRequest request, CancellationToken cancellationToken)
{
CheckIfThisInstanceIsDisposed_ForPlacementAtTopOfPublicMethods();
if (customerThrottle == null)
{
throw new ArgumentNullException(nameof(customerThrottle));
}
customerThrottle.ValidateArguments();
if (this.cancellationToken.IsNotNone())
{
return(await ExecuteThrottledAsync(customerThrottle, request, this.cancellationToken, cancellationToken).ConfigureAwait(false));
}
else
{
return(await ExecuteThrottledAsync(customerThrottle, request, cancellationToken, cancellationToken).ConfigureAwait(false));
}
}
private async Task <TResponse> ExecuteThrottledAsync(CustomerThrottle customerThrottle, TRequest request, CancellationToken cancellationTokenToCheckInternally,
CancellationToken cancellationTokenToPassToDelegate)
{
ITokenBucket tokenBucket = null;
if (customerThrottle.MaximumRequestsPerSecond > 0)
{
tokenBucket = await RetrieveMatchingTokenBucketContextOrMakeNew(customerThrottle).ConfigureAwait(false);
if (cancellationTokenToCheckInternally.IsNotNone())
{
cancellationTokenToCheckInternally.ThrowIfCancellationRequested();
}
await tokenBucket.WaitConsumeAsync(1, cancellationTokenToCheckInternally).ConfigureAwait(false);
}
if (cancellationTokenToCheckInternally.IsNotNone())
{
cancellationTokenToCheckInternally.ThrowIfCancellationRequested();
}
return(await delegateFunction(request, cancellationTokenToPassToDelegate).ConfigureAwait(false));
}
private async Task <ITokenBucket> RetrieveMatchingTokenBucketContextOrMakeNew(CustomerThrottle customerThrottle)
{
ITokenBucket tokenBucket;
if (contextDict.TryGetValue(customerThrottle.CustomerIdentityKey, out var storedThrottle))
{
if (!storedThrottle.CustomerThrottle.Equals(customerThrottle))
{
tokenBucket = await CreateAndStoreTokenBucketContext(customerThrottle).ConfigureAwait(false);
}
else // if storedThrottle.CustomerThrottle.Equals(customerThrottle)
{
tokenBucket = (ITokenBucket)storedThrottle.TokenBucket;
}
}
else // (! contextDict.TryGetValue(customerThrottle.CustomerIdentityKey, out var storedThrottle))
{
tokenBucket = await CreateAndStoreTokenBucketContext(customerThrottle).ConfigureAwait(false);
}
return(tokenBucket);
}
