Update sampling decision names (#1192)

* Rename SamplingDecision enum values

As prescribed in
https://github.com/open-telemetry/opentelemetry-specification/pull/938
and https://github.com/open-telemetry/opentelemetry-specification/pull/956.

* Include in Changelog

Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>

CHANGELOG.md

@@ -46,6 +46,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Rename `go.opentelemetry.io/otel/api/metric.ConfigureInstrument` to `NewInstrumentConfig` and
   `go.opentelemetry.io/otel/api/metric.ConfigureMeter` to `NewMeterConfig`.
 - Move the `go.opentelemetry.io/otel/api/unit` package to `go.opentelemetry.io/otel/unit`. (#1185)
+- Renamed `SamplingDecision` values to comply with OpenTelemetry specification change. (#1192)
 
 ### Fixed
 

sdk/trace/sampling.go

@@ -39,14 +39,21 @@ type SamplingParameters struct {
 	Links           []api.Link
 }
 
-// SamplingDecision indicates whether a span is recorded and sampled.
+// SamplingDecision indicates whether a span is dropped, recorded and/or sampled.
 type SamplingDecision uint8
 
 // Valid sampling decisions
 const (
-	NotRecord SamplingDecision = iota
-	Record
-	RecordAndSampled
+	// Drop will not record the span and all attributes/events will be dropped
+	Drop SamplingDecision = iota
+
+	// Record indicates the span's `IsRecording() == true`, but `Sampled` flag
+	// *must not* be set
+	RecordOnly
+
+	// RecordAndSample has span's `IsRecording() == true` and `Sampled` flag
+	// *must* be set
+	RecordAndSample
 )
 
 // SamplingResult conveys a SamplingDecision and a set of Attributes.
@@ -63,9 +70,9 @@ type traceIDRatioSampler struct {
 func (ts traceIDRatioSampler) ShouldSample(p SamplingParameters) SamplingResult {
 	x := binary.BigEndian.Uint64(p.TraceID[0:8]) >> 1
 	if x < ts.traceIDUpperBound {
-		return SamplingResult{Decision: RecordAndSampled}
+		return SamplingResult{Decision: RecordAndSample}
 	}
-	return SamplingResult{Decision: NotRecord}
+	return SamplingResult{Decision: Drop}
 }
 
 func (ts traceIDRatioSampler) Description() string {
@@ -95,7 +102,7 @@ func TraceIDRatioBased(fraction float64) Sampler {
 type alwaysOnSampler struct{}
 
 func (as alwaysOnSampler) ShouldSample(p SamplingParameters) SamplingResult {
-	return SamplingResult{Decision: RecordAndSampled}
+	return SamplingResult{Decision: RecordAndSample}
 }
 
 func (as alwaysOnSampler) Description() string {
@@ -113,7 +120,7 @@ func AlwaysSample() Sampler {
 type alwaysOffSampler struct{}
 
 func (as alwaysOffSampler) ShouldSample(p SamplingParameters) SamplingResult {
-	return SamplingResult{Decision: NotRecord}
+	return SamplingResult{Decision: Drop}
 }
 
 func (as alwaysOffSampler) Description() string {

sdk/trace/sampling_test.go

@@ -33,8 +33,8 @@ func TestParentBasedDefaultLocalParentSampled(t *testing.T) {
 		SpanID:     spanID,
 		TraceFlags: api.FlagsSampled,
 	}
-	if sampler.ShouldSample(SamplingParameters{ParentContext: parentCtx}).Decision != RecordAndSampled {
-		t.Error("Sampling decision should be RecordAndSampled")
+	if sampler.ShouldSample(SamplingParameters{ParentContext: parentCtx}).Decision != RecordAndSample {
+		t.Error("Sampling decision should be RecordAndSample")
 	}
 }
 
@@ -46,8 +46,8 @@ func TestParentBasedDefaultLocalParentNotSampled(t *testing.T) {
 		TraceID: traceID,
 		SpanID:  spanID,
 	}
-	if sampler.ShouldSample(SamplingParameters{ParentContext: parentCtx}).Decision != NotRecord {
-		t.Error("Sampling decision should be NotRecord")
+	if sampler.ShouldSample(SamplingParameters{ParentContext: parentCtx}).Decision != Drop {
+		t.Error("Sampling decision should be Drop")
 	}
 }
 
@@ -55,13 +55,13 @@ func TestParentBasedWithNoParent(t *testing.T) {
 	params := SamplingParameters{}
 
 	sampler := ParentBased(AlwaysSample())
-	if sampler.ShouldSample(params).Decision != RecordAndSampled {
-		t.Error("Sampling decision should be RecordAndSampled")
+	if sampler.ShouldSample(params).Decision != RecordAndSample {
+		t.Error("Sampling decision should be RecordAndSample")
 	}
 
 	sampler = ParentBased(NeverSample())
-	if sampler.ShouldSample(params).Decision != NotRecord {
-		t.Error("Sampling decision should be NotRecord")
+	if sampler.ShouldSample(params).Decision != Drop {
+		t.Error("Sampling decision should be Drop")
 	}
 }
 
@@ -77,28 +77,28 @@ func TestParentBasedWithSamplerOptions(t *testing.T) {
 			WithLocalParentSampled(NeverSample()),
 			false,
 			true,
-			NotRecord,
+			Drop,
 		},
 		{
 			"localParentNotSampled",
 			WithLocalParentNotSampled(AlwaysSample()),
 			false,
 			false,
-			RecordAndSampled,
+			RecordAndSample,
 		},
 		{
 			"remoteParentSampled",
 			WithRemoteParentSampled(NeverSample()),
 			true,
 			true,
-			NotRecord,
+			Drop,
 		},
 		{
 			"remoteParentNotSampled",
 			WithRemoteParentNotSampled(AlwaysSample()),
 			true,
 			false,
-			RecordAndSampled,
+			RecordAndSample,
 		},
 	}
 
@@ -126,13 +126,13 @@ func TestParentBasedWithSamplerOptions(t *testing.T) {
 			)
 
 			switch tc.expectedDecision {
-			case RecordAndSampled:
+			case RecordAndSample:
 				if sampler.ShouldSample(params).Decision != tc.expectedDecision {
-					t.Error("Sampling decision should be RecordAndSampled")
+					t.Error("Sampling decision should be RecordAndSample")
 				}
-			case NotRecord:
+			case Drop:
 				if sampler.ShouldSample(params).Decision != tc.expectedDecision {
-					t.Error("Sampling decision should be NotRecord")
+					t.Error("Sampling decision should be Drop")
 				}
 			}
 		})
@@ -181,8 +181,8 @@ func TestTraceIdRatioSamplesInclusively(t *testing.T) {
 			traceID := idg.NewTraceID()
 
 			params := SamplingParameters{TraceID: traceID}
-			if samplerLo.ShouldSample(params).Decision == RecordAndSampled {
-				require.Equal(t, RecordAndSampled, samplerHi.ShouldSample(params).Decision,
+			if samplerLo.ShouldSample(params).Decision == RecordAndSample {
+				require.Equal(t, RecordAndSample, samplerHi.ShouldSample(params).Decision,
 					"%s sampled but %s did not", samplerLo.Description(), samplerHi.Description())
 			}
 		}

sdk/trace/span.go

@@ -426,7 +426,7 @@ func makeSamplingDecision(data samplingData) SamplingResult {
 			Attributes:      data.attributes,
 			Links:           data.links,
 		})
-		if sampled.Decision == RecordAndSampled {
+		if sampled.Decision == RecordAndSample {
 			spanContext.TraceFlags |= apitrace.FlagsSampled
 		} else {
 			spanContext.TraceFlags &^= apitrace.FlagsSampled
@@ -434,7 +434,7 @@ func makeSamplingDecision(data samplingData) SamplingResult {
 		return sampled
 	}
 	if data.parent.TraceFlags&apitrace.FlagsSampled != 0 {
-		return SamplingResult{Decision: RecordAndSampled}
+		return SamplingResult{Decision: RecordAndSample}
 	}
-	return SamplingResult{Decision: NotRecord}
+	return SamplingResult{Decision: Drop}
 }

sdk/trace/trace_test.go

@@ -138,9 +138,9 @@ type testSampler struct {
 func (ts *testSampler) ShouldSample(p SamplingParameters) SamplingResult {
 	ts.callCount++
 	ts.t.Logf("called sampler for name %q", p.Name)
-	decision := NotRecord
+	decision := Drop
 	if strings.HasPrefix(p.Name, ts.prefix) {
-		decision = RecordAndSampled
+		decision = RecordAndSample
 	}
 	return SamplingResult{Decision: decision, Attributes: []label.KeyValue{label.Int("callCount", ts.callCount)}}
 }