public CircuitBreakerFactory(IMetricEvents metricEvents, IFailurePercentageCircuitBreakerConfig breakerConfig, IMjolnirLogFactory logFactory)
{
_metricEvents = metricEvents ?? throw new ArgumentNullException(nameof(metricEvents));
_breakerConfig = breakerConfig ?? throw new ArgumentNullException(nameof(breakerConfig));
_logFactory = logFactory ?? throw new ArgumentNullException(nameof(logFactory));
_log = logFactory.CreateLog <FailurePercentageCircuitBreaker>();
if (_log == null)
{
throw new InvalidOperationException($"{nameof(IMjolnirLogFactory)} implementation returned null from {nameof(IMjolnirLogFactory.CreateLog)} for type {typeof(CircuitBreakerFactory)}, please make sure the implementation returns a non-null log for all calls to {nameof(IMjolnirLogFactory.CreateLog)}");
}
_timer = new GaugeTimer(state =>
{
try
{
var keys = _circuitBreakers.Keys;
foreach (var key in keys)
{
if (_circuitBreakers.TryGetValue(key, out Lazy <FailurePercentageCircuitBreaker> lazy) && lazy.IsValueCreated)
{
var breaker = lazy.Value;
_metricEvents.BreakerGauge(
breaker.Name,
_breakerConfig.GetMinimumOperations(key),
_breakerConfig.GetWindowMillis(key),
_breakerConfig.GetThresholdPercentage(key),
_breakerConfig.GetTrippedDurationMillis(key),
_breakerConfig.GetForceTripped(key),
_breakerConfig.GetForceFixed(key),
breaker.IsTripped(),
breaker.Metrics.SuccessCount,
breaker.Metrics.FailureCount);
}
}
}
catch (Exception e)
{
_log.Error($"Error sending {nameof(IMetricEvents.BreakerGauge)} metric event", e);
}
});
}
/// <summary>
/// </summary>
/// <returns><code>true</code> if this breaker is allowing operations through</returns>
public bool IsAllowing()
{
var result = true;
if (_config.GetForceTripped(_key))
{
result = false;
}
else if (_config.GetForceFixed(_key))
{
// If we're forcing, we still want to keep track of the state in case we remove the force.
CheckAndSetTripped();
result = true;
}
else
{
result = !CheckAndSetTripped() || AllowSingleTest();
}
return(result);
}
