/// <inheritdoc/>
public void Delete()
{
try
{
PersistentStorageHelper.RemoveFile(this.FullPath);
}
catch (Exception ex)
{
PersistentStorageEventSource.Log.Warning($"Deletion of file blob {this.FullPath} has failed.", ex);
}
}
/// <inheritdoc/>
public IEnumerable <IPersistentBlob> GetBlobs()
{
var retentionDeadline = DateTime.UtcNow - TimeSpan.FromMilliseconds(this.retentionPeriodInMilliseconds);
foreach (var file in Directory.EnumerateFiles(this.directoryPath, "*.blob", SearchOption.TopDirectoryOnly).OrderByDescending(f => f))
{
DateTime fileDateTime = PersistentStorageHelper.GetDateTimeFromBlobName(file);
if (fileDateTime > retentionDeadline)
{
yield return(new FileBlob(file));
}
}
}
private bool CheckStorageSize()
{
var size = PersistentStorageHelper.GetDirectorySize();
if (size >= this.maxSizeInBytes)
{
// TODO: check accuracy of size reporting.
PersistentStorageEventSource.Log.Warning($"Persistent storage max capacity has been reached. Currently at {size / 1024} KB. " +
"Please consider increasing the value of storage max size in exporter config.");
return(false);
}
return(true);
}
private void OnMaintenanceEvent(object source, ElapsedEventArgs e)
{
try
{
if (!Directory.Exists(this.directoryPath))
{
Directory.CreateDirectory(this.directoryPath);
}
}
catch (Exception ex)
{
PersistentStorageEventSource.Log.Error($"Error creating directory {this.directoryPath}", ex);
return;
}
PersistentStorageHelper.RemoveExpiredBlobs(this.directoryPath, this.retentionPeriodInMilliseconds, this.writeTimeoutInMilliseconds);
}
/// <inheritdoc/>
public IPersistentBlob CreateBlob(byte[] buffer, int leasePeriodMilliseconds = 0)
{
if (!this.CheckStorageSize())
{
return(null);
}
try
{
var blobFilePath = Path.Combine(this.directoryPath, PersistentStorageHelper.GetUniqueFileName(".blob"));
var blob = new FileBlob(blobFilePath);
return(blob.Write(buffer, leasePeriodMilliseconds));
}
catch (Exception ex)
{
PersistentStorageEventSource.Log.Warning("CreateBlob has failed.", ex);
return(null);
}
}
/// <summary>
/// Initializes a new instance of the <see cref="FileStorage"/>
/// class.
/// </summary>
/// <param name="path">
/// Sets file storage folder location where blobs are stored.
/// </param>
/// <param name="maxSizeInBytes">
/// Maximum allowed storage folder size.
/// Default is 50 MB.
/// </param>
/// <param name="maintenancePeriodInMilliseconds">
/// Maintenance event runs at specified interval.
/// Removes expired leases and blobs that exceed retention period.
/// Default is 2 minutes.
/// </param>
/// <param name="retentionPeriodInMilliseconds">
/// Retention period in milliseconds for the blob.
/// Default is 2 days.
/// </param>
/// <param name="writeTimeoutInMilliseconds">
/// Controls the timeout when writing a buffer to blob.
/// Default is 1 minute.
/// </param>
public FileStorage(
string path,
long maxSizeInBytes = 52428800,
int maintenancePeriodInMilliseconds = 120000,
long retentionPeriodInMilliseconds = 172800000,
int writeTimeoutInMilliseconds = 60000)
{
if (path == null)
{
throw new ArgumentNullException(nameof(path));
}
// TODO: Validate time period values
this.directoryPath = PersistentStorageHelper.CreateSubdirectory(path);
this.maxSizeInBytes = maxSizeInBytes;
this.retentionPeriodInMilliseconds = retentionPeriodInMilliseconds;
this.writeTimeoutInMilliseconds = writeTimeoutInMilliseconds;
this.maintenanceTimer = new Timer(maintenancePeriodInMilliseconds);
this.maintenanceTimer.Elapsed += this.OnMaintenanceEvent;
this.maintenanceTimer.AutoReset = true;
this.maintenanceTimer.Enabled = true;
}
/// <inheritdoc/>
public IPersistentBlob Write(byte[] buffer, int leasePeriodMilliseconds = 0)
{
string path = this.FullPath + ".tmp";
try
{
PersistentStorageHelper.WriteAllBytes(path, buffer);
if (leasePeriodMilliseconds > 0)
{
var timestamp = DateTime.UtcNow + TimeSpan.FromMilliseconds(leasePeriodMilliseconds);
this.FullPath += $"@{timestamp:yyyy-MM-ddTHHmmss.fffffffZ}.lock";
}
File.Move(path, this.FullPath);
}
catch (Exception ex)
{
PersistentStorageEventSource.Log.Warning($"Writing a blob to file {path} has failed.", ex);
return(null);
}
return(this);
}
