public async Task WhenCachedBlocksHitTripLevel_ThenStallsUntilWriteOperationSucceeds()
{
var blocks = new List <IList <BlockData> >();
Action <IReadOnlyCollection <BlockData>, CancellationToken> saveBlocks = (d, ct) => blocks.Add(d.ToList());
var failWrite = true;
_writerMock
.Setup(w => w.WriteAsync(It.IsAny <IReadOnlyCollection <BlockData> >(), It.IsAny <CancellationToken>()))
.Returns(() => TaskHelpers.CreateCompletedTask(!Volatile.Read(ref failWrite)))
.Callback(saveBlocks);
var context = MockPartitionContext.CreateWithNoopCheckpoint("0");
await _processor.OpenAsync(context);
// first N requests fail but go through (the first batch will not fill a frame so it won't result in a write operation)
for (int i = 0; i < CircuitBreakerStallLevel + 1; i++)
{
var batch = new[] { CreateEventData((byte)('a' + i), MaxBlockSize - 200 - i), };
Task processTask = _processor.ProcessEventsAsync(context, batch);
await AssertExt.CompletesBeforeTimeoutAsync(processTask, TimeoutInterval);
}
// N+1th stalls and waits for cached frames to be flushed
{
var batch = new[] { CreateEventData((byte)('a' + CircuitBreakerStallLevel + 2), 10), };
Task processTask = _processor.ProcessEventsAsync(context, batch);
await AssertExt.DoesNotCompleteBeforeTimeoutAsync(processTask, TimeoutInterval);
// let the write operation through
Volatile.Write(ref failWrite, false);
await AssertExt.CompletesBeforeTimeoutAsync(processTask, TimeoutInterval);
// check the stalled entries were written
var bufferedBlocks = blocks.Last();
Assert.Equal(CircuitBreakerStallLevel, bufferedBlocks.Count);
for (int i = 0; i < CircuitBreakerStallLevel; i++)
{
var lines = GetPayloadsFromBlock(bufferedBlocks[i]);
Assert.Equal(1, lines.Length);
Assert.Equal(
new string((char)('a' + i), MaxBlockSize - 200 - i),
lines[0]);
}
}
}