public void SetDefaultSampleRates(IEnumerable <KeyValuePair <string, float> > sampleRates)
{
// to avoid locking if writers and readers can access the dictionary at the same time,
// build the new dictionary first, then replace the old one
var rates = new Dictionary <SampleRateKey, float>();
if (sampleRates != null)
{
foreach (var pair in sampleRates)
{
// No point in adding default rates
if (pair.Value == 1.0f)
{
continue;
}
var key = SampleRateKey.Parse(pair.Key);
if (key == null)
{
Log.Warning("Could not parse sample rate key {SampleRateKey}", pair.Key);
continue;
}
rates.Add(key.Value, pair.Value);
}
}
_sampleRates = rates;
}
public float GetSamplingRate(Span span)
{
Log.Debug("Using the default sampling logic");
if (_sampleRates.Count == 0)
{
return(1);
}
string env;
if (span.Tags is CommonTags tags)
{
env = tags.Environment;
}
else
{
env = span.GetTag(Tags.Env);
}
var service = span.ServiceName;
var key = new SampleRateKey(service, env);
if (_sampleRates.TryGetValue(key, out var sampleRate))
{
span.SetMetric(Metrics.SamplingAgentDecision, sampleRate);
return(sampleRate);
}
Log.Debug("Could not establish sample rate for trace {TraceId}", span.TraceId);
return(1);
}
