/// <summary>
/// Refreshes the cache for the given set of files if expired
/// </summary>
public async Task RefreshCacheAsync(IEnumerable <CacheFileMetadata> librariesCacheMetadata, ILogger logger, CancellationToken cancellationToken)
{
await ParallelUtility.ForEachAsync(DownloadFileIfNecessaryAsync, MaxConcurrentDownloads, librariesCacheMetadata, cancellationToken).ConfigureAwait(false);
async Task DownloadFileIfNecessaryAsync(CacheFileMetadata metadata)
{
if (!File.Exists(metadata.DestinationPath))
{
logger.Log(string.Format(Resources.Text.DownloadingFile, metadata.Source), LogLevel.Operation);
await DownloadToFileAsync(metadata.Source, metadata.DestinationPath, attempts : 5, cancellationToken : cancellationToken).ConfigureAwait(false);
}
}
}
public async Task ForEachAsync_CancellationTokenSet_DoesNotRunAllTasks()
{
int counter = 0;
var cts = new CancellationTokenSource();
Exception exception = await Assert.ThrowsExceptionAsync <TaskCanceledException>(async() =>
await ParallelUtility.ForEachAsync((i) =>
{
if (i % 2 == 0)
{
cts.Cancel();
}
counter++;
return(Task.CompletedTask);
}, 1, Enumerable.Range(1, 3), cts.Token)
);
Assert.AreEqual(2, counter); // both 1 and 2 ran, but operation was cancelled before 3
}
public async Task ForEachAsync_IfMultipleTasksFail_AllTasksGetRun_OnlyFirstExceptionIsReported()
{
int counter = 0;
Exception exception = await Assert.ThrowsExceptionAsync <Exception>(async() =>
await ParallelUtility.ForEachAsync((i) =>
{
if (i % 2 == 0)
{
throw new Exception($"Expected Failure (iteration {i})");
}
counter++;
return(Task.CompletedTask);
}, 1, Enumerable.Range(1, 5))
);
Assert.AreEqual("Expected Failure (iteration 2)", exception.Message);
Assert.AreEqual(3, counter); // both 1, 3, and 5 ran, 2 and 4 threw the exception
}
public async Task ForEachAsync_IfOneTaskFails_AllTasksGetRun()
{
int counter = 0;
Exception exception = await Assert.ThrowsExceptionAsync <Exception>(async() =>
await ParallelUtility.ForEachAsync((i) =>
{
if (i % 2 == 0)
{
throw new Exception("Expected Failure");
}
counter++;
return(Task.CompletedTask);
}, 1, Enumerable.Range(1, 3))
);
Assert.AreEqual("Expected Failure", exception.Message);
Assert.AreEqual(2, counter); // both 1 and 3 ran, 2 threw the exception
}
public async Task ForEachAsync_ValidEmptyArguments_ShouldRunWithoutExceptions()
{
await ParallelUtility.ForEachAsync((i) => Task.CompletedTask, 1, Array.Empty <object>());
}
public async Task ForEachAsync_NullItems_ShouldThrow()
{
await Assert.ThrowsExceptionAsync <ArgumentNullException>(async() =>
await ParallelUtility.ForEachAsync((i) => Task.CompletedTask, 1, (object[])null)
);
}
public async Task ForEachAsync_NegativeDegreesParallelism_ShouldThrow()
{
await Assert.ThrowsExceptionAsync <ArgumentOutOfRangeException>(async() =>
await ParallelUtility.ForEachAsync((i) => Task.CompletedTask, -5, Array.Empty <object>())
);
}
public async Task ForEachAsync_NullAction_ShouldThrow()
{
await Assert.ThrowsExceptionAsync <ArgumentNullException>(async() =>
await ParallelUtility.ForEachAsync(null, 1, Array.Empty <object>())
);
}
