public void ComplexScrollAllObservable()
{
int numberOfSlices = Environment.ProcessorCount;
var scrollAllObservable = Client.ScrollAll <Project>("10s", numberOfSlices, sc => sc
.MaxDegreeOfParallelism(numberOfSlices)
.Search(s => s
.Query(q => q
.Term(f => f.State, StateOfBeing.Stable)
)
)
);
var waitHandle = new ManualResetEvent(false);
ExceptionDispatchInfo info = null;
var scrollAllObserver = new ScrollAllObserver <Project>(
onNext: response => ProcessResponse(response.SearchResponse), // <1> do something with the response
onError: e =>
{
info = ExceptionDispatchInfo.Capture(e); // <2> if an exception is thrown, capture it to throw outside of the observer
waitHandle.Set();
},
onCompleted: () => waitHandle.Set()
);
scrollAllObservable.Subscribe(scrollAllObserver); // <3> initiate scrolling
waitHandle.WaitOne(); // <4> block the current thread until the wait handle is set
info?.Throw(); // <5> if an exception was captured whilst scrolling, throw it
}
private void ScrollAll(string index, int numberOfShards, int numberOfDocuments)
{
var handle = new ManualResetEvent(false);
var scrollObservable = this._client.ScrollAll <SmallObject>("1m", numberOfShards, s => s
.MaxDegreeOfParallelism(numberOfShards / 2)
.Search(search => search
.Index(index)
.AllTypes()
.MatchAll()
)
);
//we set up an observer
var seenDocuments = 0;
var seenSlices = new ConcurrentBag <int>();
//since we call allTypes search should be bounded to index.
var scrollObserver = new ScrollAllObserver <SmallObject>(
onError: (e) => { handle.Set(); throw e; },
onCompleted: () => handle.Set(),
onNext: (b) =>
{
seenSlices.Add(b.Slice);
Interlocked.Add(ref seenDocuments, b.SearchResponse.Hits.Count);
}
);
//when we subscribe the observable becomes hot
scrollObservable.Subscribe(scrollObserver);
handle.WaitOne(TimeSpan.FromMinutes(5));
seenDocuments.Should().Be(numberOfDocuments);
var groups = seenSlices.GroupBy(s => s).ToList();
groups.Count().Should().Be(numberOfShards);
groups.Should().OnlyContain(g => g.Count() > 1);
}