instr(spans): Measure span metrics extraction time (#2373)

In preparation of #2355, measure
how much time span metrics extraction currently costs.

relay-server/src/metrics_extraction/spans/mod.rs

@@ -11,6 +11,7 @@ use crate::metrics_extraction::spans::types::SpanMetric;
 
 use crate::metrics_extraction::transactions::types::ExtractMetricsError;
 use crate::metrics_extraction::IntoMetric;
+use crate::statsd::RelayTimers;
 
 mod types;
 
@@ -21,7 +22,15 @@ pub(crate) fn extract_span_metrics(
  aggregator_config: &AggregatorConfig,
  event: &Event,
 ) -> Result<Vec<Metric>, ExtractMetricsError> {
- // TODO(iker): measure the performance of this whole method
+ relay_statsd::metric!(timer(RelayTimers::EventProcessingSpanMetricsExtraction), {
+ extract_span_metrics_inner(aggregator_config, event)
+ })
+}
+
+fn extract_span_metrics_inner(
+ aggregator_config: &AggregatorConfig,
+ event: &Event,
+) -> Result<Vec<Metric>, ExtractMetricsError> {
  let mut metrics = Vec::new();
 
  if event.ty.value() != Some(&EventType::Transaction) {

relay-server/src/statsd.rs

@@ -207,6 +207,8 @@ pub enum RelayTimers {
  EventProcessingPii,
  /// Time spent converting the event from its in-memory reprsentation into a JSON string.
  EventProcessingSerialization,
+ /// Time used to extract span metrics from an event.
+ EventProcessingSpanMetricsExtraction,
  /// Time spent between the start of request handling and processing of the envelope.
  ///
  /// This includes streaming the request body, scheduling overheads, project config fetching,
@@ -329,6 +331,9 @@ impl TimerMetric for RelayTimers {
  #[cfg(feature = "processing")]
  RelayTimers::EventProcessingRateLimiting => "event_processing.rate_limiting",
  RelayTimers::EventProcessingPii => "event_processing.pii",
+ RelayTimers::EventProcessingSpanMetricsExtraction => {
+ "event_processing.span_metrics_extraction"
+ }
  RelayTimers::EventProcessingSerialization => "event_processing.serialization",
  RelayTimers::EnvelopeWaitTime => "event.wait_time",
  RelayTimers::EnvelopeProcessingTime => "event.processing_time",