public async Task RetryMetadataOnFailedWaitAsync()
{
var options = new FixedWindowRateLimiterOptions
{
PermitLimit = 2,
QueueProcessingOrder = QueueProcessingOrder.OldestFirst,
QueueLimit = 1,
Window = TimeSpan.FromSeconds(20),
AutoReplenishment = false
};
var limiter = new FixedWindowRateLimiter(options);
using var lease = limiter.AttemptAcquire(2);
var failedLease = await limiter.AcquireAsync(2);
Assert.False(failedLease.IsAcquired);
Assert.True(failedLease.TryGetMetadata(MetadataName.RetryAfter.Name, out var metadata));
var metaDataTime = Assert.IsType <TimeSpan>(metadata);
Assert.Equal(options.Window.Ticks, metaDataTime.Ticks);
Assert.True(failedLease.TryGetMetadata(MetadataName.RetryAfter, out var typedMetadata));
Assert.Equal(options.Window.Ticks, typedMetadata.Ticks);
Assert.Collection(failedLease.MetadataNames, item => item.Equals(MetadataName.RetryAfter.Name));
}
public void Create_FixedWindow()
{
var options = new FixedWindowRateLimiterOptions(1, QueueProcessingOrder.OldestFirst, 10, TimeSpan.FromMinutes(1), true);
var partition = RateLimitPartition.GetFixedWindowLimiter(1, key => options);
var limiter = partition.Factory(1);
var fixedWindowLimiter = Assert.IsType <FixedWindowRateLimiter>(limiter);
Assert.Equal(options.PermitLimit, fixedWindowLimiter.GetAvailablePermits());
Assert.Equal(options.Window, fixedWindowLimiter.ReplenishmentPeriod);
Assert.False(fixedWindowLimiter.IsAutoReplenishing);
}
public async Task CorrectRetryMetadataWithNonZeroAvailableItems()
{
var options = new FixedWindowRateLimiterOptions(3, QueueProcessingOrder.OldestFirst, 1,
TimeSpan.FromSeconds(20), autoReplenishment: false);
var limiter = new FixedWindowRateLimiter(options);
using var lease = limiter.Acquire(2);
var failedLease = await limiter.WaitAsync(3);
Assert.False(failedLease.IsAcquired);
Assert.True(failedLease.TryGetMetadata(MetadataName.RetryAfter, out var typedMetadata));
Assert.Equal(options.Window.Ticks, typedMetadata.Ticks);
}
/// <summary>
/// Defines a partition with a <see cref="FixedWindowRateLimiter"/> with the given <see cref="FixedWindowRateLimiterOptions"/>.
/// </summary>
/// <remarks>
/// Set <see cref="FixedWindowRateLimiterOptions.AutoReplenishment"/> to <see langword="false"/> to save an allocation. This method will create a new options type and set <see cref="FixedWindowRateLimiterOptions.AutoReplenishment"/> to <see langword="false"/> otherwise.
/// </remarks>
/// <typeparam name="TKey">The type to distinguish partitions with.</typeparam>
/// <param name="partitionKey">The specific key for this partition.</param>
/// <param name="factory">The function called when a rate limiter for the given <paramref name="partitionKey"/> is needed. This can return the same instance of <see cref="FixedWindowRateLimiterOptions"/> across different calls.</param>
/// <returns></returns>
public static RateLimitPartition <TKey> GetFixedWindowLimiter <TKey>(
TKey partitionKey,
Func <TKey, FixedWindowRateLimiterOptions> factory)
{
return(Get(partitionKey, key =>
{
FixedWindowRateLimiterOptions options = factory(key);
// We don't want individual FixedWindowRateLimiters to have timers. We will instead have our own internal Timer handling all of them
if (options.AutoReplenishment is true)
{
options = new FixedWindowRateLimiterOptions(options.PermitLimit, options.QueueProcessingOrder, options.QueueLimit,
options.Window, autoReplenishment: false);
}
return new FixedWindowRateLimiter(options);
}));
}
public async Task CorrectRetryMetadataWithQueuedItem()
{
var options = new FixedWindowRateLimiterOptions(2, QueueProcessingOrder.OldestFirst, 1,
TimeSpan.FromSeconds(20), autoReplenishment: false);
var limiter = new FixedWindowRateLimiter(options);
using var lease = limiter.Acquire(2);
// Queue item which changes the retry after time for failed items
var wait = limiter.WaitAsync(1);
Assert.False(wait.IsCompleted);
var failedLease = await limiter.WaitAsync(2);
Assert.False(failedLease.IsAcquired);
Assert.True(failedLease.TryGetMetadata(MetadataName.RetryAfter, out var typedMetadata));
Assert.Equal(options.Window.Ticks, typedMetadata.Ticks);
}
/// <summary>
/// Adds a new <see cref="FixedWindowRateLimiter"/> with the given <see cref="FixedWindowRateLimiterOptions"/> to the <see cref="RateLimiterOptions"/>.
/// </summary>
/// <param name="options">The <see cref="RateLimiterOptions"/> to add a limiter to.</param>
/// <param name="policyName">The name that will be associated with the limiter.</param>
/// <param name="configureOptions">A callback to configure the <see cref="FixedWindowRateLimiterOptions"/> to be used for the limiter.</param>
/// <returns>This <see cref="RateLimiterOptions"/>.</returns>
public static RateLimiterOptions AddFixedWindowLimiter(this RateLimiterOptions options, string policyName, Action <FixedWindowRateLimiterOptions> configureOptions)
{
ArgumentNullException.ThrowIfNull(configureOptions);
var key = new PolicyNameKey()
{
PolicyName = policyName
};
var fixedWindowRateLimiterOptions = new FixedWindowRateLimiterOptions();
configureOptions.Invoke(fixedWindowRateLimiterOptions);
// Saves an allocation in GetFixedWindowLimiter, which would have created a new set of options if this was true.
fixedWindowRateLimiterOptions.AutoReplenishment = false;
return(options.AddPolicy(policyName, context =>
{
return RateLimitPartition.GetFixedWindowLimiter(key,
_ => fixedWindowRateLimiterOptions);
}));
}