/// <summary>
/// Switch Modes.
/// </summary>
/// <remarks>
/// Reader works in 2 modes. Cached, or direct. This routine allows us to switch between these 2 modes.
/// Switch is expected to happen when a replica become primary (switch to cached) and when it loses primary status.
/// </remarks>
/// <param name="newMode"></param>
/// <param name="token"></param>
/// <returns></returns>
public async Task SwitchModeAsync(DataReaderMode newMode, CancellationToken token)
{
if (newMode == this.dataReaderMode)
{
EventStoreLogger.Logger.LogMessage("Target Mode: {0} == Current Mode. No-Op", this.dataReaderMode);
return;
}
EventStoreLogger.Logger.LogMessage("Current Mode: {0}, New Mode: {1}", this.dataReaderMode, newMode);
// We do the switch under lock.
await this.singleAccess.WaitAsync(token).ConfigureAwait(false);
try
{
if (this.azureAccessObject != null)
{
EventStoreLogger.Logger.LogMessage("Releasing Azure Access Object");
await this.azureAccessObject.ReleaseAccessAsync(token).ConfigureAwait(false);
this.azureAccessObject = null;
}
this.dataReaderMode = newMode;
this.initialized = false;
}
finally
{
this.singleAccess.Release();
}
await this.InitIfRequiredAsync(token).ConfigureAwait(false);
}
public EventStoreReader(DataReaderMode readingMode)
{
this.dataReaderMode = readingMode;
this.initialized = false;
this.singleAccess = new SemaphoreSlim(1);
}
