// ReSharper restore NotAccessedField.Local
internal SemaphoreSlimIsolationSemaphore(GroupKey key, IConfigurableValue<int> maxConcurrent, IStats stats, IConfigurableValue<long> gaugeIntervalMillisOverride = null)
{
_key = key;
if (stats == null)
{
throw new ArgumentNullException("stats");
}
_stats = stats;
// Note: Changing the semaphore maximum at runtime is not currently supported.
_maxConcurrent = maxConcurrent.Value;
_semaphore = new SemaphoreSlim(_maxConcurrent);
_timer = new GaugeTimer((source, args) =>
{
var count = _semaphore.CurrentCount;
_stats.Gauge(StatsPrefix + " available", (count == 0 ? "Full" : "Available"), count);
}, gaugeIntervalMillisOverride);
}
internal FailurePercentageCircuitBreaker(GroupKey key, IClock clock, ICommandMetrics metrics, IStats stats, IMetricEvents metricEvents, FailurePercentageCircuitBreakerProperties properties, IConfigurableValue<long> gaugeIntervalMillisOverride = null)
{
_key = key;
_clock = clock;
_metrics = metrics;
if (stats == null)
{
throw new ArgumentNullException("stats");
}
if (metricEvents == null)
{
throw new ArgumentNullException("metricEvents");
}
_stats = stats;
_metricEvents = metricEvents;
Properties = properties;
_state = State.Fixed; // Start off assuming everything's fixed.
_lastTrippedTimestamp = 0; // 0 is fine since it'll be far less than the first compared value.
// Old gauge, will be phased out in v3.0 when IStats are removed.
_statsTimer = new GaugeTimer((source, args) =>
{
var snapshot = _metrics.GetSnapshot();
_stats.Gauge(StatsPrefix + " total", snapshot.Total >= properties.MinimumOperations.Value ? "Above" : "Below", snapshot.Total);
_stats.Gauge(StatsPrefix + " error", snapshot.ErrorPercentage >= properties.ThresholdPercentage.Value ? "Above" : "Below", snapshot.ErrorPercentage);
}, gaugeIntervalMillisOverride);
_metricsTimer = new GaugeTimer((source, args) =>
{
_metricEvents.BreakerConfigGauge(
Name,
Properties.MinimumOperations.Value,
Properties.ThresholdPercentage.Value,
Properties.TrippedDurationMillis.Value);
}, ConfigGaugeIntervalMillis);
}
public SemaphoreBulkheadHolder(GroupKey key, IMetricEvents metricEvents)
{
if (metricEvents == null)
{
throw new ArgumentNullException("metricEvents");
}
_metricEvents = metricEvents;
// The order of things here is very intentional.
// We create the configurable value first, retrieve its current value, and then
// initialize the semaphore bulkhead. We register the change handler after that.
// That ought to help avoid a situation where we might fire a config change handler
// before we add the semaphore to the dictionary, potentially trying to add two
// entries with different values in rapid succession.
var configKey = "mjolnir.bulkhead." + key + ".maxConcurrent";
_config = new ConfigurableValue<int>(configKey, DefaultBulkheadMaxConcurrent);
var value = _config.Value;
_bulkhead = new SemaphoreBulkhead(key, value);
// On change, we'll replace the bulkhead. The assumption here is that a caller
// using the bulkhead will have kept a local reference to the bulkhead that they
// acquired a lock on, and will release the lock on that bulkhead and not one that
// has been replaced after a config change.
_config.AddChangeHandler(newLimit =>
{
if (newLimit < 0)
{
Log.ErrorFormat("Semaphore bulkhead config {0} changed to an invalid limit of {0}, the bulkhead will not be changed",
configKey,
newLimit);
return;
}
_bulkhead = new SemaphoreBulkhead(key, newLimit);
});
_timer = new GaugeTimer((source, args) =>
{
_metricEvents.BulkheadConfigGauge(_bulkhead.Name, "semaphore", _config.Value);
}, ConfigGaugeIntervalMillis);
}