async Task <TResult> ReadQueryCheckpoint <TResult>(FlowKey key, Func <TResult> getDefault, Func <ResolvedEvent, TResult> getCheckpoint)
{
var stream = key.GetCheckpointStream();
EventReadResult result = default(EventReadResult);
try
{
result = await _context.Connection.ReadEventAsync(stream, StreamPosition.End, resolveLinkTos : false);
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
switch (result.Status)
{
case EventReadStatus.NoStream:
case EventReadStatus.NotFound:
return(getDefault());
case EventReadStatus.Success:
return(getCheckpoint(result.Event.Value));
default:
throw new Exception($"Unexpected result when reading {stream}: {result.Status}");
}
}
public async Task <FlowResumeInfo> ReadFlowResumeInfo(FlowKey key)
{
var stream = key.GetCheckpointStream();
var result = await _context.Connection.ReadEventAsync(stream, StreamPosition.End, resolveLinkTos : false);
switch (result.Status)
{
case EventReadStatus.NoStream:
return(await new ReadFlowWithoutCheckpointCommand(_context, key).Execute());
case EventReadStatus.Success:
return(await new ReadFlowWithCheckpointCommand(_context, key, result.Event?.Event).Execute());
default:
throw new Exception($"Unexpected result when reading {stream} to resume: {result.Status}");
}
}
internal async Task <FlowInfo> Execute()
{
var stream = _key.GetCheckpointStream();
var result = await _context.Connection.ReadEventAsync(stream, StreamPosition.End, resolveLinkTos : false);
switch (result.Status)
{
case EventReadStatus.NoStream:
case EventReadStatus.NotFound:
return(new FlowInfo.NotFound());
case EventReadStatus.Success:
_checkpoint = result.Event.Value;
_metadata = _context.ReadCheckpointMetadata(_checkpoint);
return(ReadFlow());
default:
throw new Exception($"Unexpected result when reading {stream}: {result.Status}");
}
}