public async Task <IAsyncCursor <BsonDocument> > GetCursor(ResumeToken resumeToken,
IEnumerable <string> collections,
CancellationToken cancellationToken)
{
BsonValue ts;
if (resumeToken.Token != null)
{
ts = resumeToken.Token["ts"];
}
else
{
var operation = await operations
.Find(new BsonDocument())
.Sort(Builders <BsonDocument> .Sort.Descending("$natural"))
.FirstAsync(cancellationToken);
ts = operation["ts"];
}
var filter = builder.And(
builder.In("op", new[] { "i", "u", "d" }),
builder.Gt("ts", ts),
builder.In("ns", collections.Select(collectionName => $"{databaseName}.{collectionName}")),
builder.Exists("fromMigrate", false)
);
var options = new FindOptions <BsonDocument>
{
CursorType = CursorType.TailableAwait, NoCursorTimeout = true, OplogReplay = true
};
return(await operations.FindAsync(filter, options, cancellationToken));
}
private async Task <Unit> SaveEvents(ICollection <BatchItem> items, ResumeToken resumeToken)
{
if (items.Any())
{
var last = items.Last();
await events.InsertManyAsync(items.Select(item => item.Event));
resumeToken.Token = last.Token;
resumeToken.Updated = last.WallClock;
await tokens.Save(resumeToken);
logger.Information("Published {@count} event(s).", items.Count);
}
return(Unit.Default);
}