Created
December 21, 2015 12:28
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Nest Bulk Searcher
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using System; | |
using System.Collections.Generic; | |
using System.Linq; | |
using System.Reactive.Linq; | |
using System.Reactive.Subjects; | |
using System.Threading; | |
using System.Threading.Tasks; | |
using Nest; | |
using _____.Managers; | |
namespace _____.Block | |
{ | |
public class NestBulkSearcher<T> : INestBulkSearcher<T> where T : class | |
{ | |
internal class NestSearchOperation | |
{ | |
public Func<SearchDescriptor<T>, SearchDescriptor<T>> Operation { get; set; } | |
public ISearchResponse<T> Response { get; set; } | |
public CancellationTokenSource Cts { get; set; } | |
public Exception Error { get; set; } | |
} | |
private readonly Subject<NestSearchOperation> _subject; | |
private readonly TimeSpan _maxTaskWait; | |
public IElasticClient Client { get; } | |
public NestBulkSearcher(IElasticClient nest, BulkPublisherConfig config) | |
: this(nest, config.MsearchSize, config.PublishFrequency, config.Tolerance) | |
{ | |
} | |
public NestBulkSearcher(IElasticClient nest, int bufferLimit, TimeSpan publishFrequency, TimeSpan tolerance) | |
{ | |
Client = nest; | |
_subject = new Subject<NestSearchOperation>(); | |
_maxTaskWait = tolerance; | |
// Publish items every so often | |
Observable | |
.Concat(_subject) | |
.Buffer(publishFrequency, bufferLimit) | |
.Subscribe(PublishBuffer); | |
} | |
/// <summary> | |
/// Executes a bulk search that will return exactly one item, or nothing. | |
/// </summary> | |
public async Task<Result<ISearchResponse<T>>> SearchAsync(Func<SearchDescriptor<T>, SearchDescriptor<T>> context) | |
{ | |
var cts = new CancellationTokenSource(); | |
var bulkOp = new NestSearchOperation | |
{ | |
Operation = context, | |
Cts = cts | |
}; | |
// Publish the operation, this will be picked up by the subscribing observable. | |
_subject.OnNext(bulkOp); | |
// This isn't great. | |
// Delay on this thread for longer than it will take the buffer to be published. Expect a cancellation. | |
try | |
{ | |
await Task.Delay(_maxTaskWait, cts.Token).ConfigureAwait(false); | |
} | |
catch (TaskCanceledException tce) | |
{ | |
} | |
// If the cancellation wasn't requested, then the bulk response didn't get sent | |
if (!cts.IsCancellationRequested) | |
{ | |
return Result<ISearchResponse<T>>.SetException(new ApplicationException("The msearch request was not sent within the expected time limit.")); | |
} | |
return bulkOp.Response?.IsValid ?? false | |
? Result<ISearchResponse<T>>.SetValue(bulkOp.Response) | |
: Result<ISearchResponse<T>>.SetException(bulkOp.Response?.RequestInformation.OriginalException | |
?? bulkOp.Error | |
?? new ApplicationException("An unknown error occurred with the msearch request.")); | |
} | |
private void PublishBuffer(IList<NestSearchOperation> currentBuffer) | |
{ | |
if (!currentBuffer.Any()) | |
{ | |
return; | |
} | |
var searchDescriptor = new MultiSearchDescriptor(); | |
foreach (var searchOp in currentBuffer) | |
{ | |
searchDescriptor.Search(searchOp.Operation); | |
} | |
try | |
{ | |
var bulkResponse = Client.MultiSearch(searchDescriptor); | |
var items = bulkResponse.GetResponses<T>().ToList(); | |
// Set response values and release all waiting tasks | |
var zip = currentBuffer.Zip(items, (op, result) => new { op, result }); | |
foreach (var a in zip) | |
{ | |
a.op.Response = a.result; | |
a.op.Cts.Cancel(); | |
} | |
} | |
catch (Exception e) | |
{ | |
foreach (var op in currentBuffer) | |
{ | |
op.Error = e; | |
op.Cts.Cancel(); | |
} | |
} | |
} | |
} | |
} |
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