public Task <ChangeResult> WriteAsync(Atom ns, Atom queue, Event evt)
{
const int MONGO_KEY_VIOLATION = 11000;
checkRoute(ns, queue);
var ve = evt.NonNull(nameof(Event)).Validate();
if (ve != null)
{
throw ve;
}
//Checkpoint is forced as the time of writing to disk at the client
var bson = BsonConvert.ToBson(evt);
var collection = getQueueCollection(ns, queue);//ensures indexes
var crud = collection.Insert(bson);
//need to detect key violation as it is a sign of idempotency retry which should be treated as success
var success = (crud.WriteErrors == null) ||
(crud.WriteErrors.Length > 0 && crud.WriteErrors[0].Code == MONGO_KEY_VIOLATION);
var result = success ? new ChangeResult(ChangeResult.ChangeType.Inserted, 1, "Affected: " + crud.TotalDocumentsAffected, crud.WriteErrors?.Select(e => new { e.Code, e.Message }))
: new ChangeResult(ChangeResult.ChangeType.Undefined, 0, "Error", crud.WriteErrors?.Select(e => new { e.Code, e.Message }));
return(Task.FromResult(result));
}
public Task <IEnumerable <Event> > FetchAsync(Atom ns, Atom queue, ulong checkpoint, int skip, int count, bool onlyid)
{
checkRoute(ns, queue);
var collection = getQueueCollection(ns, queue);
var qry = BsonConvert.GetFetchQuery(checkpoint);
var selector = BsonConvert.GetFetchSelector(onlyid);
IEnumerable <Event> result = null;
if (skip < 0)
{
skip = 0;
}
count = count.KeepBetween(1, EventHubClientLogic.FETCH_BY_MAX);
var fetchBy = Math.Min(count, EventHubClientLogic.FETCH_BY_MAX);
using (var cursor = collection.Find(qry, skip, fetchBy, selector))
{
result = cursor.Take(count)
.Select(doc => BsonConvert.FromBson(doc)).ToArray();
}
return(Task.FromResult(result));
}
private Collection getQueueCollection(Atom ns, Atom queue)
{
var db = getNamespaceDatabase(ns);
var collection = db.GetOrRegister(queue.Value, out var wasAdded);
if (wasAdded)
{
//Create index on CheckpointUtc
this.DontLeak(
() => db.RunCommand(BsonConvert.CreateIndex(queue.Value)),
errorLogType: Azos.Log.MessageType.CriticalAlert
);
}
return(collection);
}
