public async Task RunUpdate(CancellationToken cancellationToken)
{
try
{
// One thread per server
var allSources = _updateItems
.SelectMany(x => x.DownloadSources.Keys)
.Distinct();
var runningTasks = new List <Tuple <Task, DownloadSourceInfo> >();
foreach (var updateSource in allSources)
{
var updateSourceInfo = new DownloadSourceInfo(updateSource);
var task = Task.Run(async() => await UpdateThread(updateSourceInfo, cancellationToken),
cancellationToken);
runningTasks.Add(new Tuple <Task, DownloadSourceInfo>(task, updateSourceInfo));
}
await Task.WhenAll(runningTasks.Select(x => x.Item1));
cancellationToken.ThrowIfCancellationRequested();
}
catch (OperationCanceledException)
{
foreach (var updateItem in _updateItems)
{
if (updateItem.Status == UpdateDownloadStatus.Downloading || updateItem.Status == UpdateDownloadStatus.Waiting)
{
updateItem.MarkAsCancelled();
}
}
throw;
}
}
/// <summary>
/// Thead handling a single server.
/// It looks for updates that can be downloaded from that server and picks what it can download.
/// When no more work is available the task finishes.
/// </summary>
private async Task UpdateThread(DownloadSourceInfo updateSource, CancellationToken cancellationToken)
{
Exception failReason = null;
try
{
// Exit early if the source keeps failing
var failCount = 0;
while (!cancellationToken.IsCancellationRequested)
{
UpdateDownloadItem currentDownloadItem = null;
UpdateItem currentlyDownloading = null;
lock (_updateItems)
{
currentDownloadItem = _updateItems.FirstOrDefault(x =>
x.Status == UpdateDownloadStatus.Waiting &&
x.DownloadSources.ContainsKey(updateSource.Source));
if (currentDownloadItem != null)
{
currentDownloadItem.Status = UpdateDownloadStatus.Downloading;
currentlyDownloading = currentDownloadItem.DownloadSources[updateSource.Source];
}
}
if (currentlyDownloading == null || cancellationToken.IsCancellationRequested)
{
Console.WriteLine($"Closing source downloader {updateSource.Source.Origin}");
return;
}
var progress = new Progress <double>(percent => currentDownloadItem.FinishPercent = percent);
try
{
currentDownloadItem.FinishPercent = 0;
await RetryHelper.RetryOnExceptionAsync(
() => currentlyDownloading.Update(progress, cancellationToken), 3, TimeSpan.FromSeconds(3),
cancellationToken);
currentDownloadItem.FinishPercent = 100;
currentDownloadItem.Status = UpdateDownloadStatus.Finished;
failCount = 0;
}
catch (Exception e)
{
if (e is OperationCanceledException)
{
currentDownloadItem.MarkAsCancelled(e);
if (cancellationToken.IsCancellationRequested)
{
return;
}
else
{
continue;
}
}
Console.WriteLine(
$"Marking source {updateSource.Source.Origin} as broken because of exception: {e.ToStringDemystified()}");
lock (_updateItems)
{
currentDownloadItem.TryMarkSourceAsFailed(updateSource.Source, e);
currentDownloadItem.FinishPercent = 0;
}
// Give the source a couple of chances before ditching it
if (++failCount >= 2)
{
failReason = e;
return;
}
}
}
}
finally
{
if (failReason != null)
{
lock (_updateItems)
{
var e = new DownloadSourceCrashedException("Update source " + updateSource.Source.Origin + " closed early because of other issues", updateSource.Source, failReason);
foreach (var updateTask in _updateItems)
{
updateTask.TryMarkSourceAsFailed(updateSource.Source, e);
}
}
}
}
}
