/// <summary>
/// Keeps trying to checkout a guild (with backoff) until either maxTimeout has been hit,
/// or a value has been returned that's not Locked.
/// </summary>
/// <param name="repo">A repo. May not be null.</param>
/// <param name="guildId">An id associated with a guild.</param>
/// <param name="maxTimeout">The maximum amount of time to spend waiting for this to unlock.</param>
/// <param name="recycleResult">A preallocated result that should be returned if passed in.</param>
/// <returns>The result.</returns>
public static async Task <GuildCheckoutResult> WaitForNotLockedCheckout(
this IGuildRepository repo,
Snowflake guildId,
TimeSpan maxTimeout,
GuildCheckoutResult recycleResult = null)
{
Stopwatch timer = new Stopwatch();
var retVal = recycleResult ?? new GuildCheckoutResult();
TimeSpan nextDelay = TimeSpan.FromMilliseconds(1);
timer.Start();
retVal = await repo.Checkout(guildId, retVal);
while (retVal.Result == GuildCheckoutResult.ResultType.Locked &&
timer.Elapsed + nextDelay < maxTimeout)
{
await Task.Delay(nextDelay);
retVal = await repo.Checkout(guildId, retVal);
nextDelay *= 1.5;
}
return(retVal);
}
/// <summary>
/// Checkout out a <see cref="Guild"/>.
/// </summary>
/// <param name="guildId">An id representing a guild.</param>
/// <param name="recycleResult">A preallocated result that should be returned if passed in.</param>
/// <returns>The borrowed guild.</returns>
public async Task <GuildCheckoutResult> Checkout(Snowflake guildId, GuildCheckoutResult recycleResult = null)
{
var retVal = recycleResult ?? new GuildCheckoutResult();
try
{
string blobName = AzureBlobGuildRepository.GetBlobName(guildId);
var blobClient = this.blobContainerClient.GetBlockBlobClient(blobName);
// Aquire a lease on the blob
var blobLeaseClient = blobClient.GetBlobLeaseClient();
var leaseResult = await blobLeaseClient.AcquireAsync(AzureBlobGuildRepository.BlobLeaseDuration).ConfigureAwait(false);
var lease = leaseResult.Value;
Guild guild;
using (var sourceStream = await blobClient.OpenReadAsync())
using (var streamReader = new StreamReader(sourceStream))
using (var jsonReader = new JsonTextReader(streamReader))
{
guild = GuildConverter.FromJToken(guildId, await JObject.ReadFromAsync(jsonReader));
}
retVal.ToSuccess(new Borrowed <Guild>(
isntance: guild,
data: lease,
onReturn: this.ReturnGuild));
return(retVal);
}
catch (RequestFailedException e)
{
if (e.Status == AzureBlobGuildRepository.NotFoundStatus)
{
retVal.ToDoesNotExist();
return(retVal);
}
else if (e.Status == AzureBlobGuildRepository.ConflictStatus && "LeaseAlreadyPresent".Equals(e.ErrorCode, StringComparison.OrdinalIgnoreCase))
{
retVal.ToLocked();
return(retVal);
}
else
{
throw;
}
}
}
/// <summary>
/// Checkout out or create a <see cref="Guild"/> if one does not exist.
/// </summary>
/// <param name="guildId">An id representing a guild.</param>
/// <param name="recycleResult">A preallocated result that should be returned if passed in.</param>
/// <returns>The borrowed guild.</returns>
public async Task <GuildCheckoutResult> Checkout(Snowflake guildId, GuildCheckoutResult recycleResult = null)
{
var retVal = recycleResult ?? new GuildCheckoutResult();
try
{
var sourceStream = new FileStream(
FileBasedGuildRepository.GetFilePath(guildId),
FileMode.Open,
FileAccess.ReadWrite,
FileShare.None,
bufferSize: 4096,
useAsync: true);
var streamReader = new StreamReader(sourceStream);
var jsonReader = new JsonTextReader(streamReader);
var guild = GuildConverter.FromJToken(guildId, await JObject.ReadFromAsync(jsonReader));
retVal.ToSuccess(new Borrowed <Guild>(
isntance: guild,
data: sourceStream,
onReturn: FileBasedGuildRepository.ReturnGuild));
return(retVal);
}
catch (FileNotFoundException)
{
retVal.ToDoesNotExist();
return(retVal);
}
catch (IOException e)
{
if (e.HResult == FileBasedGuildRepository.LockedFileHRResult)
{
retVal.ToLocked();
return(retVal);
}
else
{
throw;
}
}
}
