void WaitForEmptyQueue(LiteQueue <int> queue)
{
while (queue.Count() > 0 && !_consumerFailed)
{
Thread.Sleep(5);
}
}
LiteQueue <T> CreateQueue <T>()
{
var logCollection = _db.GetCollection <QueueEntry <T> >(_collectionName);
var logs = new LiteQueue <T>(logCollection);
return(logs);
}
void Consumer(LiteQueue <int> queue)
{
try
{
while (_keepRunning)
{
var entry = queue.Dequeue();
if (entry != null)
{
if (!_consumedRecords.Add(entry.Payload))
{
throw new DuplicateException(entry.Payload);
}
queue.Commit(entry);
}
else
{
Thread.Sleep(1);
}
}
}
catch
{
_consumerFailed = true;
throw;
}
}
public void Duplicate()
{
var queue = new LiteQueue <int>(_db, _collectionName);
Action producer = delegate() { BadProducer(queue); };
Action consumer = delegate() { Consumer(queue); };
RunTasks(producer, consumer, producerCount: 1, consumerCount: 1);
}
public void MultipleProducersMultipleConsumers()
{
var queue = new LiteQueue <int>(_db, _collectionName);
Action producer = delegate() { Producer(queue); };
Action consumer = delegate() { Consumer(queue); };
RunTasks(producer, consumer, producerCount: 10, consumerCount: 10);
}
void BadProducer(LiteQueue <int> queue)
{
for (int i = 0; i < _recordsToProduce; i++)
{
int next = 1; // Should cause DuplicateException in consumer
queue.Enqueue(next);
}
}
void Producer(LiteQueue <int> queue)
{
for (int i = 0; i < _recordsToProduce; i++)
{
int next = Interlocked.Increment(ref _producerCounter);
queue.Enqueue(next);
}
}
static void Main(string[] args)
{
// LiteQueue depends on LiteDB. You can save other things to same database.
using (var db = new LiteDatabase("Queue.db"))
{
// Creates a "logs" collection in LiteDB. You can also pass a user defined object.
var logs = new LiteQueue <string>(db, "logs");
// Recommended on startup to reset anything that was checked out but not committed or aborted.
// Or call CurrentCheckouts to inspect them and abort yourself. See github page for
// notes regarding duplicate messages.
logs.ResetOrphans();
// Adds record to queue
logs.Enqueue("Test");
// Get next item from queue. Marks it as checked out such that other threads that
// call Checkout will not see it - but does not remove it from the queue.
var record = logs.Dequeue();
try
{
// Do something that may potentially fail, i.e. a network call
// ...
// Removes record from queue
logs.Commit(record);
}
catch
{
// Returns the record to the queue
logs.Abort(record);
}
}
Console.WriteLine("Done");
Console.ReadLine();
}
/// <summary>
/// Runs a multi-threaded producer/consumer test
/// </summary>
/// <param name="producerCount"># of producer threads to run</param>
/// <param name="consumerCount"># of consumer threads to run</param>
/// <param name="producer">Function to run for each producer</param>
/// <param name="consumer">Function to run for each consumer</param>
void RunTasks(Action producer, Action consumer, int producerCount, int consumerCount)
{
var queue = new LiteQueue <int>(_db, _collectionName);
List <Task> producers = new List <Task>();
for (int i = 0; i < producerCount; i++)
{
Task producerTask = new Task(producer);
producers.Add(producerTask);
producerTask.Start();
}
List <Task> consumers = new List <Task>();
for (int i = 0; i < consumerCount; i++)
{
Task consumerTask = new Task(consumer);
consumers.Add(consumerTask);
consumerTask.Start();
}
Task.WaitAll(producers.ToArray());
WaitForEmptyQueue(queue);
_keepRunning = false;
try
{
Task.WaitAll(consumers.ToArray());
}
catch (AggregateException ex)
{
throw ex.InnerException;
}
VerifyAllConsumed(producerCount);
}
public void Ctor_DbCollectionName()
{
var logs = new LiteQueue <string>(_db, _collectionName);
Assert.AreEqual(0, logs.Count());
}