/// <summary>
/// Resets the current snapshot and returns the previous one as the result.
/// </summary>
/// <returns>Returns the previous snapshot.</returns>
public DnsMetricSnapshot ResetSnapshot()
{
DnsMetricSnapshot previousSnapshot = this.snapshot;
Interlocked.Exchange(ref this.snapshot, new DnsMetricSnapshot());
return(previousSnapshot);
}
/// <summary>
/// Logs metrics periodically to the console.
/// </summary>
private void LogMetrics()
{
try
{
// Print out total and period values.
var metricOutput = new StringBuilder();
metricOutput.AppendLine("==========DNS Metrics==========");
metricOutput.AppendLine();
metricOutput.AppendFormat(this.MetricsOutputFormat, "Snapshot Time", this.dateTimeProvider.GetAdjustedTime());
metricOutput.AppendLine();
// Metrics since start.
metricOutput.AppendLine(">>> Metrics since start");
metricOutput.AppendFormat(this.MetricsOutputFormat, "Total DNS Requests", this.metrics.DnsRequestCountSinceStart);
metricOutput.AppendFormat(this.MetricsOutputFormat, "Total DNS Server Failures (Restarted)", this.metrics.DnsServerFailureCountSinceStart);
metricOutput.AppendFormat(this.MetricsOutputFormat, "Total DNS Request Failures", this.metrics.DnsRequestFailureCountSinceStart);
metricOutput.AppendFormat(this.MetricsOutputFormat, "Maximum Peer Count", this.metrics.MaxPeerCountSinceStart);
metricOutput.AppendLine();
// Reset period values.
DnsMetricSnapshot snapshot = this.metrics.ResetSnapshot();
// Calculate averages.
double averagePeerCount = snapshot.DnsRequestCountSinceLastPeriod == 0 ? 0 : snapshot.PeerCountSinceLastPeriod / snapshot.DnsRequestCountSinceLastPeriod;
double averageElapsedTicks = snapshot.DnsRequestCountSinceLastPeriod == 0 ? 0 : snapshot.DnsRequestElapsedTicksSinceLastPeriod / snapshot.DnsRequestCountSinceLastPeriod;
// Metrics since last period.
metricOutput.AppendLine($">>> Metrics for last period ({MetricsLogRate} secs)");
metricOutput.AppendFormat(this.MetricsOutputFormat, "DNS Requests", snapshot.DnsRequestCountSinceLastPeriod);
metricOutput.AppendFormat(this.MetricsOutputFormat, "DNS Server Failures (Restarted)", snapshot.DnsServerFailureCountSinceLastPeriod);
metricOutput.AppendFormat(this.MetricsOutputFormat, "DNS Request Failures", snapshot.DnsRequestFailureCountSinceLastPeriod);
metricOutput.AppendFormat(this.MetricsOutputFormat, "Average Peer Count", averagePeerCount);
metricOutput.AppendFormat(this.MetricsOutputFormat, "Last Peer Count", snapshot.LastPeerCount);
metricOutput.AppendFormat(this.MetricsOutputFormat, "Average Elapsed Time Processing DNS Requests (ms)", new TimeSpan((long)averageElapsedTicks).TotalMilliseconds);
metricOutput.AppendFormat(this.MetricsOutputFormat, "Last Elapsed Time Processing DNS Requests (ms)", new TimeSpan(snapshot.LastDnsRequestElapsedTicks).TotalMilliseconds);
metricOutput.AppendLine();
// Output.
this.logger.LogInformation(metricOutput.ToString());
}
catch (Exception e)
{
// If metrics fail, just log.
this.logger.LogWarning(e, "Failed to output DNS metrics.");
}
}
