/// <summary>
/// Obtains an updated version of Configuration.
/// </summary>
/// <param name="cancel">CancellationToken</param>
/// <returns>Configuration of type T.</returns>
/// <remarks>If the time since the last call is less than <see cref="AutomaticRefreshInterval"/> then <see cref="IConfigurationRetriever{T}.GetConfigurationAsync"/> is not called and the current Configuration is returned.</remarks>
public async Task <T> GetConfigurationAsync(CancellationToken cancel)
{
DateTimeOffset now = DateTimeOffset.UtcNow;
if (_currentConfiguration != null && _syncAfter > now)
{
return(_currentConfiguration);
}
await _refreshLock.WaitAsync(cancel).ConfigureAwait(false);
try
{
if (_syncAfter <= now)
{
try
{
// Don't use the individual CT here, this is a shared operation that shouldn't be affected by an individual's cancellation.
// The transport should have it's own timeouts, etc..
_currentConfiguration = await _configRetriever.GetConfigurationAsync(_metadataAddress, _docRetriever, CancellationToken.None).ConfigureAwait(false);
Contract.Assert(_currentConfiguration != null);
_lastRefresh = now;
_syncAfter = DateTimeUtil.Add(now.UtcDateTime, _automaticRefreshInterval);
}
catch (Exception ex)
{
_syncAfter = DateTimeUtil.Add(now.UtcDateTime, _automaticRefreshInterval < _refreshInterval ? _automaticRefreshInterval : _refreshInterval);
if (_currentConfiguration == null) // Throw an exception if there's no configuration to return.
{
throw LogHelper.LogExceptionMessage(new InvalidOperationException(LogHelper.FormatInvariant(LogMessages.IDX20803, (_metadataAddress ?? "null")), ex));
}
else
{
LogHelper.LogExceptionMessage(new InvalidOperationException(LogHelper.FormatInvariant(LogMessages.IDX20806, (_metadataAddress ?? "null")), ex));
}
}
}
// Stale metadata is better than no metadata
if (_currentConfiguration != null)
{
return(_currentConfiguration);
}
else
{
throw LogHelper.LogExceptionMessage(new InvalidOperationException(LogHelper.FormatInvariant(LogMessages.IDX20803, (_metadataAddress ?? "null"))));
}
}
finally
{
_refreshLock.Release();
}
}
/// <summary>
/// Obtains an updated version of Configuration.
/// </summary>
/// <param name="cancel">CancellationToken</param>
/// <returns>Configuration of type T.</returns>
/// <remarks>If the time since the last call is less than <see cref="AutomaticRefreshInterval"/> then <see cref="IConfigurationRetriever{T}.GetConfigurationAsync"/> is not called and the current Configuration is returned.</remarks>
public async Task <T> GetConfigurationAsync(CancellationToken cancel)
{
DateTimeOffset now = DateTimeOffset.UtcNow;
if (_currentConfiguration != null && _syncAfter > now)
{
return(_currentConfiguration);
}
await _refreshLock.WaitAsync(cancel);
try
{
Exception retrieveEx = null;
if (_syncAfter <= now)
{
try
{
// Don't use the individual CT here, this is a shared operation that shouldn't be affected by an individual's cancellation.
// The transport should have it's own timeouts, etc..
_currentConfiguration = await _configRetriever.GetConfigurationAsync(_metadataAddress, _docRetriever, CancellationToken.None);
Contract.Assert(_currentConfiguration != null);
_lastRefresh = now;
_syncAfter = DateTimeUtil.Add(now.UtcDateTime, _automaticRefreshInterval);
}
catch (Exception ex)
{
retrieveEx = ex;
_syncAfter = DateTimeUtil.Add(now.UtcDateTime, _automaticRefreshInterval < _refreshInterval ? _automaticRefreshInterval : _refreshInterval);
}
}
if (_currentConfiguration == null)
{
throw new InvalidOperationException(string.Format(CultureInfo.InvariantCulture, ErrorMessages.IDX10803, _metadataAddress ?? "null"), retrieveEx);
}
// Stale metadata is better than no metadata
return(_currentConfiguration);
}
finally
{
_refreshLock.Release();
}
}