public override Flow <EventStreamElement <TE>, Done, NotUsed> Handle()
{
return(Flow.FromFunction(
new Func <EventStreamElement <TE>, Done>(
element =>
{
if (EventHandlers.TryGetValue(element.Event.GetType(), out var dbAction))
{
DbActionExecutor(element, dbAction);
}
else
{
// TODO: log the unhandled event
}
using (var con = ReadSideConnectionFactory.Invoke())
{
con.Execute(@"
update read_side_offsets
set sequence_offset = @offset
where read_side_id = @readSideId
and tag = @tag",
new
{
offset = (element.Offset as Sequence).Value,
readSideId = ReadSideId,
tag = ((element.Event as AggregateEvent <TE>).AggregateTag as AggregateEventTag).Tag
});
}
return Done.Instance;
}
)
));
}
public override Task <Done> GlobalPrepare()
{
using (var con = ReadSideConnectionFactory.Invoke())
{
con.Execute(@"
if not exists (select * from sysobjects where name='read_side_offsets' and xtype='U')
CREATE TABLE read_side_offsets (read_side_id VARCHAR(255), tag VARCHAR(255),sequence_offset bigint, time_uuid_offset char(36),PRIMARY KEY (read_side_id, tag))
");
GlobalPrepareCallback(con);
}
return(base.GlobalPrepare());
}
public virtual void DbActionExecutor(EventStreamElement <TE> element, Action <SqlConnection, EventStreamElement <TE> > action)
{
try
{
using (var con = ReadSideConnectionFactory.Invoke())
action(con, element);
}
catch (Exception ex)
{
throw;
}
}
public override Task <Offset> Prepare(AggregateEventTag tag)
{
using (var con = ReadSideConnectionFactory.Invoke())
{
var offset = con.QueryFirstOrDefault <long>(@"
select sequence_offset
from read_side_offsets
where read_side_id = @readSideId
and tag = @tag
", new
{
readSideId = ReadSideId,
tag = tag.Tag
});
return(Task.FromResult(
Offset.Sequence(
offset
)
));
}
}