test

DataDog · Nov 6, 2024 · 14c43d4 · 14c43d4
1 parent 00fe7ee
commit 14c43d4
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Showing 2 changed files with 21 additions and 3 deletions.
diff --git a/ddtrace/tracer/rules_sampler.go b/ddtrace/tracer/rules_sampler.go
@@ -510,23 +510,39 @@ func (rs *traceRulesSampler) sampleRules(span *span) bool {
 }
 
 func (rs *traceRulesSampler) applyRate(span *span, rate float64, now time.Time, sampler samplernames.SamplerName) {
+	fmt.Printf("[DEBUG] knuthFactor: %d\n", knuthFactor)
+	fmt.Printf("[DEBUG] Entering applyRate with rate: %f for span: %s, TraceID: %d\n", rate, span.Name, span.TraceID)
 	span.Lock()
 	defer span.Unlock()
 
 	span.setMetric(keyRulesSamplerAppliedRate, rate)
 	delete(span.Metrics, keySamplingPriorityRate)
-	if !sampledByRate(span.TraceID, rate) {
+
+	// Calculate sampling decision
+	samplingCalc := span.TraceID * knuthFactor
+	threshold := uint64(rate * math.MaxUint64)
+	shouldSample := samplingCalc < threshold
+
+	fmt.Printf("[DEBUG] Sampling calculation: TraceID=%d, knuthFactor=%d, calc=%d, threshold=%d, shouldSample=%v\n",
+		span.TraceID, knuthFactor, samplingCalc, threshold, shouldSample)
+
+	if !shouldSample {
+		fmt.Printf("[DEBUG] Rejecting trace due to sampling rate\n")
 		span.setSamplingPriorityLocked(ext.PriorityUserReject, sampler)
 		return
 	}
 
-	sampled, rate := rs.limiter.allowOne(now)
+	sampled, limitRate := rs.limiter.allowOne(now)
+	fmt.Printf("[DEBUG] Rate limiter decision: sampled=%v, rate=%f\n", sampled, limitRate)
+
 	if sampled {
+		fmt.Printf("[DEBUG] Keeping trace: passed both sampling and rate limiting\n")
 		span.setSamplingPriorityLocked(ext.PriorityUserKeep, sampler)
 	} else {
+		fmt.Printf("[DEBUG] Rejecting trace: failed rate limiting\n")
 		span.setSamplingPriorityLocked(ext.PriorityUserReject, sampler)
 	}
-	span.setMetric(keyRulesSamplerLimiterRate, rate)
+	span.setMetric(keyRulesSamplerLimiterRate, limitRate)
 }
 
 // limit returns the rate limit set in the rules sampler, controlled by DD_TRACE_RATE_LIMIT, and

diff --git a/ddtrace/tracer/sampler.go b/ddtrace/tracer/sampler.go
@@ -7,6 +7,7 @@ package tracer
 
 import (
 	"encoding/json"
+	"fmt"
 	"io"
 	"math"
 	"sync"
@@ -84,6 +85,7 @@ func (r *rateSampler) Sample(spn ddtrace.Span) bool {
 // sampledByRate verifies if the number n should be sampled at the specified
 // rate.
 func sampledByRate(n uint64, rate float64) bool {
+	fmt.Printf("[DEBUG] Rate: %f", rate)
 	if rate < 1 {
 		return n*knuthFactor < uint64(rate*math.MaxUint64)
 	}