/// <summary>
/// Read data entries and their corresponding eTags from the Azure table.
/// </summary>
/// <param name="filter">Filter string to use for querying the table and filtering the results.</param>
/// <returns>Enumeration of entries in the table which match the query condition.</returns>
public async Task <IEnumerable <Tuple <T, string> > > ReadTableEntriesAndEtagsAsync(string filter)
{
const string operation = "ReadTableEntriesAndEtags";
var startTime = DateTime.UtcNow;
try
{
TableQuery <T> cloudTableQuery = filter == null
? new TableQuery <T>()
: new TableQuery <T>().Where(filter);
try
{
Func <Task <List <T> > > executeQueryHandleContinuations = async() =>
{
TableQuerySegment <T> querySegment = null;
var list = new List <T>();
//ExecuteSegmentedAsync not supported in "WindowsAzure.Storage": "7.2.1" yet
while (querySegment == null || querySegment.ContinuationToken != null)
{
querySegment = await Table.ExecuteQuerySegmentedAsync(cloudTableQuery, querySegment?.ContinuationToken);
list.AddRange(querySegment);
}
return(list);
};
#if !ORLEANS_TRANSACTIONS
IBackoffProvider backoff = new FixedBackoff(this.StoragePolicyOptions.PauseBetweenOperationRetries);
List <T> results = await AsyncExecutorWithRetries.ExecuteWithRetries(
counter => executeQueryHandleContinuations(),
this.StoragePolicyOptions.MaxOperationRetries,
(exc, counter) => AzureTableUtils.AnalyzeReadException(exc.GetBaseException(), counter, TableName, Logger),
this.StoragePolicyOptions.OperationTimeout,
backoff);
#else
List <T> results = await executeQueryHandleContinuations();
#endif
// Data was read successfully if we got to here
return(results.Select(i => Tuple.Create(i, i.ETag)).ToList());
}
catch (Exception exc)
{
// Out of retries...
var errorMsg = $"Failed to read Azure storage table {TableName}: {exc.Message}";
if (!AzureTableUtils.TableStorageDataNotFound(exc))
{
Logger.Warn((int)Utilities.ErrorCode.AzureTable_09, errorMsg, exc);
}
throw new OrleansException(errorMsg, exc);
}
}
finally
{
CheckAlertSlowAccess(startTime, operation);
}
}
