/// <summary>
/// Retry the sequence until it terminates successfully, waiting <paramref name="waitTime"/> between retries.
/// </summary>
public static IAsyncEnumerable <T> Retry <T>(this IAsyncEnumerable <T> source, TimeSpan waitTime, ITime time)
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
if (time is null)
{
time = Time.RealTime;
}
return(Create <T>(async(yield, token) =>
{
try
{
// ReSharper disable once PossibleMultipleEnumeration
await source.CopyTo(yield, token).ConfigureAwait(false);
return;
}
catch { token.ThrowIfCancellationRequested(); }
using var timer = time.GetTimer(token);
while (true)
{
try
{
await timer.Delay(waitTime).ConfigureAwait(false);
// ReSharper disable once PossibleMultipleEnumeration
await source.CopyTo(yield, token).ConfigureAwait(false);
return;
}
catch { token.ThrowIfCancellationRequested(); }
}
}));
}
/// <summary>
/// Retry the sequence, waiting between retries for each element in <paramref name="waitTimes"/>.
/// </summary>
public static IAsyncEnumerable <T> Retry <T>(this IAsyncEnumerable <T> source, IEnumerable <TimeSpan> waitTimes, ITime time)
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
if (waitTimes == null)
{
throw new ArgumentNullException(nameof(waitTimes));
}
if (time is null)
{
time = Time.RealTime;
}
return(Create <T>(async(yield, token) =>
{
Exception error;
try
{
// ReSharper disable once PossibleMultipleEnumeration
await source.CopyTo(yield, token).ConfigureAwait(false);
return;
}
catch (Exception ex)
{
token.ThrowIfCancellationRequested();
error = ex;
}
using (var timer = time.GetTimer(token))
foreach (var waitTime in waitTimes)
{
try
{
await timer.Delay(waitTime).ConfigureAwait(false);
// ReSharper disable once PossibleMultipleEnumeration
await source.CopyTo(yield, token).ConfigureAwait(false);
return;
}
catch (Exception ex)
{
token.ThrowIfCancellationRequested();
error = ex;
}
}
throw error;
}));
}
public static async Task <Channel <T> > ToUnboundedChannel <T>(
this IAsyncEnumerable <T> source,
UnboundedChannelOptions?options,
CancellationToken cancellationToken = default)
{
var channel = Channel.CreateUnbounded <T>(options ?? new UnboundedChannelOptions());
await source.CopyTo(channel, ChannelCompletionMode.CompleteAndPropagateError, cancellationToken)
.ConfigureAwait(false);
return(channel);
}
/// <summary>
/// Retry the sequence up to <paramref name="retryCount"/> times.
/// </summary>
public static IAsyncEnumerable <T> Retry <T>(this IAsyncEnumerable <T> source, int retryCount)
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
return(Create <T>(async(yield, token) =>
{
Exception error;
try
{
// ReSharper disable once PossibleMultipleEnumeration
await source.CopyTo(yield, token).ConfigureAwait(false);
return;
}
catch (Exception ex)
{
token.ThrowIfCancellationRequested();
error = ex;
}
for (var r = retryCount; r > 0; r--)
{
try
{
// ReSharper disable once PossibleMultipleEnumeration
await source.CopyTo(yield, token).ConfigureAwait(false);
return;
}
catch (Exception ex)
{
token.ThrowIfCancellationRequested();
error = ex;
}
}
throw error;
}));
}
/// <summary>
/// Catches exceptions of type <typeparamref name="TException"/>.
/// </summary>
public static IAsyncEnumerable <TSource> Catch <TSource, TException>(this IAsyncEnumerable <TSource> source) where TException : Exception
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
return(Create <TSource>(async(yield, token) =>
{
try { await source.CopyTo(yield, token).ConfigureAwait(false); }
catch (TException) { /**/ }
}));
}
/// <summary>
/// Invokes a specified async action after source observable sequence terminates normally or by an exception.
/// </summary>
public static IAsyncEnumerable <T> Finally <T>(this IAsyncEnumerable <T> source, Func <Task> @finally)
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
if (@finally == null)
{
throw new ArgumentNullException(nameof(@finally));
}
return(Create <T>(async(yield, token) =>
{
try { await source.CopyTo(yield, token).ConfigureAwait(false); }
finally { await @finally().ConfigureAwait(false); }
}));
}
/// <summary>
/// Retry the sequence until it terminates successfully.
/// </summary>
public static IAsyncEnumerable <T> Retry <T>(this IAsyncEnumerable <T> source)
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
return(Create <T>(async(yield, token) =>
{
while (true)
{
try
{
// ReSharper disable once PossibleMultipleEnumeration
await source.CopyTo(yield, token).ConfigureAwait(false);
return;
}
catch { token.ThrowIfCancellationRequested(); }
}
}));
}