/
ErrorFloodGate.cs
65 lines (56 loc) · 2.1 KB
/
ErrorFloodGate.cs
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using System;
using System.Collections.Generic;
namespace PackageExplorer
{
public class ErrorFloodGate
{
private const double StopLoadingThreshold = 0.50;
private const int SlidingExpirationInMinutes = 60;
private const int MinFailuresCount = 5;
private const int SecondsInOneTick = 5;
private readonly DateTimeOffset _origin = DateTimeOffset.Now;
private readonly Queue<int> _attempts = new Queue<int>();
private readonly Queue<int> _failures = new Queue<int>();
private DateTimeOffset _lastEvaluate = DateTimeOffset.Now;
private bool _isOpen;
public bool IsOpen
{
get
{
if (GetTicks(_lastEvaluate) > 1)
{
var discardOlderThan1Hour = GetTicks(DateTimeOffset.Now.AddMinutes(-SlidingExpirationInMinutes));
ExpireOlderValues(_attempts, discardOlderThan1Hour);
ExpireOlderValues(_failures, discardOlderThan1Hour);
var attemptsCount = _attempts.Count;
var failuresCount = _failures.Count;
_isOpen = attemptsCount > 0 && failuresCount > MinFailuresCount && ((double)failuresCount / attemptsCount) > StopLoadingThreshold;
_lastEvaluate = DateTimeOffset.Now;
}
return _isOpen;
}
}
private void ExpireOlderValues(Queue<int> q, int expirationOffsetInTicks)
{
while (q.Count > 0 && q.Peek() < expirationOffsetInTicks)
{
q.Dequeue();
}
}
public void ReportAttempt()
{
var ticks = GetTicks(_origin);
_attempts.Enqueue(ticks);
}
public void ReportError()
{
int ticks = GetTicks(_origin);
_failures.Enqueue(ticks);
}
// Ticks here are of 5sec long
private int GetTicks(DateTimeOffset origin)
{
return (int)((DateTimeOffset.Now - origin).TotalSeconds / SecondsInOneTick);
}
}
}