Update propagation to conform with OpenTelemetry specification (#1212)

* Move propagation package contents to the otel package

* Implement package relocation

* Update propagation to OTel spec

* Add changes to changelog

* Add propagation tests

CHANGELOG.md

@@ -15,6 +15,14 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 ### Changed
 
 - Set default propagator to no-op propagator. (#1184)
+- The `HTTPSupplier`, `HTTPExtractor`, `HTTPInjector`, and `HTTPPropagator` from the `go.opentelemetry.io/otel/api/propagation` package were replaced with unified `TextMapCarrier` and `TextMapPropagator` in the `go.opentelemetry.io/otel` package. (#1212)
+- The `New` function from the `go.opentelemetry.io/otel/api/propagation` package was replaced with `NewCompositeTextMapPropagator` in the `go.opentelemetry.io/otel` package. (#1212)
+
+### Removed
+
+- The `ExtractHTTP` and `InjectHTTP` fuctions from the `go.opentelemetry.io/otel/api/propagation` package were removed. (#1212)
+- The `Propagators` interface from the `go.opentelemetry.io/otel/api/propagation` package was removed to conform to the OpenTelemetry specification.
+   The explicit `TextMapPropagator` type can be used in its place as this is the `Propagator` type the specification defines. (#1212)
 
 ### Removed
 

api/baggage/baggage_propagator.go

@@ -19,29 +19,22 @@ import (
 	"net/url"
 	"strings"
 
-	"go.opentelemetry.io/otel/api/propagation"
+	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/label"
 )
 
 // Temporary header name until W3C finalizes format.
 // https://github.com/open-telemetry/opentelemetry-specification/blob/18b2752ebe6c7f0cdd8c7b2bcbdceb0ae3f5ad95/specification/correlationcontext/api.md#header-name
 const baggageHeader = "otcorrelations"
 
-// Baggage propagates Key:Values in W3C CorrelationContext
-// format.
+// Baggage propagates Key:Values in W3C CorrelationContext format.
 // nolint:golint
 type Baggage struct{}
 
-var _ propagation.HTTPPropagator = Baggage{}
+var _ otel.TextMapPropagator = Baggage{}
 
-// DefaultHTTPPropagator returns the default context correlation HTTP
-// propagator.
-func DefaultHTTPPropagator() propagation.HTTPPropagator {
-	return Baggage{}
-}
-
-// Inject implements HTTPInjector.
-func (b Baggage) Inject(ctx context.Context, supplier propagation.HTTPSupplier) {
+// Inject set baggage key-values from the Context into the carrier.
+func (b Baggage) Inject(ctx context.Context, carrier otel.TextMapCarrier) {
 	baggageMap := MapFromContext(ctx)
 	firstIter := true
 	var headerValueBuilder strings.Builder
@@ -57,13 +50,13 @@ func (b Baggage) Inject(ctx context.Context, supplier propagation.HTTPSupplier)
 	})
 	if headerValueBuilder.Len() > 0 {
 		headerString := headerValueBuilder.String()
-		supplier.Set(baggageHeader, headerString)
+		carrier.Set(baggageHeader, headerString)
 	}
 }
 
-// Extract implements HTTPExtractor.
-func (b Baggage) Extract(ctx context.Context, supplier propagation.HTTPSupplier) context.Context {
-	baggage := supplier.Get(baggageHeader)
+// Extract reads baggage key-values from the carrier into a returned Context.
+func (b Baggage) Extract(ctx context.Context, carrier otel.TextMapCarrier) context.Context {
+	baggage := carrier.Get(baggageHeader)
 	if baggage == "" {
 		return ctx
 	}
@@ -112,7 +105,7 @@ func (b Baggage) Extract(ctx context.Context, supplier propagation.HTTPSupplier)
 	return ctx
 }
 
-// GetAllKeys implements HTTPPropagator.
-func (b Baggage) GetAllKeys() []string {
+// Fields returns the keys who's values are set with Inject.
+func (b Baggage) Fields() []string {
 	return []string{baggageHeader}
 }

api/baggage/baggage_propagator_test.go

@@ -22,13 +22,13 @@ import (
 
 	"github.com/google/go-cmp/cmp"
 
+	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/api/baggage"
-	"go.opentelemetry.io/otel/api/propagation"
 	"go.opentelemetry.io/otel/label"
 )
 
 func TestExtractValidBaggageFromHTTPReq(t *testing.T) {
-	props := propagation.New(propagation.WithExtractors(baggage.Baggage{}))
+	prop := otel.TextMapPropagator(baggage.Baggage{})
 	tests := []struct {
 		name    string
 		header  string
@@ -90,7 +90,7 @@ func TestExtractValidBaggageFromHTTPReq(t *testing.T) {
 			req.Header.Set("otcorrelations", tt.header)
 
 			ctx := context.Background()
-			ctx = propagation.ExtractHTTP(ctx, props, req.Header)
+			ctx = prop.Extract(ctx, req.Header)
 			gotBaggage := baggage.MapFromContext(ctx)
 			wantBaggage := baggage.NewMap(baggage.MapUpdate{MultiKV: tt.wantKVs})
 			if gotBaggage.Len() != wantBaggage.Len() {
@@ -117,7 +117,7 @@ func TestExtractValidBaggageFromHTTPReq(t *testing.T) {
 }
 
 func TestExtractInvalidDistributedContextFromHTTPReq(t *testing.T) {
-	props := propagation.New(propagation.WithExtractors(baggage.Baggage{}))
+	prop := otel.TextMapPropagator(baggage.Baggage{})
 	tests := []struct {
 		name   string
 		header string
@@ -152,7 +152,7 @@ func TestExtractInvalidDistributedContextFromHTTPReq(t *testing.T) {
 
 			ctx := baggage.NewContext(context.Background(), tt.hasKVs...)
 			wantBaggage := baggage.MapFromContext(ctx)
-			ctx = propagation.ExtractHTTP(ctx, props, req.Header)
+			ctx = prop.Extract(ctx, req.Header)
 			gotBaggage := baggage.MapFromContext(ctx)
 			if gotBaggage.Len() != wantBaggage.Len() {
 				t.Errorf(
@@ -176,7 +176,6 @@ func TestExtractInvalidDistributedContextFromHTTPReq(t *testing.T) {
 
 func TestInjectBaggageToHTTPReq(t *testing.T) {
 	propagator := baggage.Baggage{}
-	props := propagation.New(propagation.WithInjectors(propagator))
 	tests := []struct {
 		name         string
 		kvs          []label.KeyValue
@@ -229,7 +228,7 @@ func TestInjectBaggageToHTTPReq(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			req, _ := http.NewRequest("GET", "http://example.com", nil)
 			ctx := baggage.ContextWithMap(context.Background(), baggage.NewMap(baggage.MapUpdate{MultiKV: tt.kvs}))
-			propagation.InjectHTTP(ctx, props, req.Header)
+			propagator.Inject(ctx, req.Header)
 
 			gotHeader := req.Header.Get("otcorrelations")
 			wantedLen := len(strings.Join(tt.wantInHeader, ","))
@@ -252,7 +251,7 @@ func TestInjectBaggageToHTTPReq(t *testing.T) {
 func TestTraceContextPropagator_GetAllKeys(t *testing.T) {
 	var propagator baggage.Baggage
 	want := []string{"otcorrelations"}
-	got := propagator.GetAllKeys()
+	got := propagator.Fields()
 	if diff := cmp.Diff(got, want); diff != "" {
 		t.Errorf("GetAllKeys: -got +want %s", diff)
 	}

api/global/internal/state.go

@@ -18,8 +18,8 @@ import (
 	"sync"
 	"sync/atomic"
 
+	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/api/metric"
-	"go.opentelemetry.io/otel/api/propagation"
 	"go.opentelemetry.io/otel/api/trace"
 )
 
@@ -33,7 +33,7 @@ type (
 	}
 
 	propagatorsHolder struct {
-		pr propagation.Propagators
+		tm otel.TextMapPropagator
 	}
 )
 
@@ -90,14 +90,14 @@ func SetMeterProvider(mp metric.MeterProvider) {
 	globalMeter.Store(meterProviderHolder{mp: mp})
 }
 
-// Propagators is the internal implementation for global.Propagators.
-func Propagators() propagation.Propagators {
-	return globalPropagators.Load().(propagatorsHolder).pr
+// TextMapPropagator is the internal implementation for global.TextMapPropagator.
+func TextMapPropagator() otel.TextMapPropagator {
+	return globalPropagators.Load().(propagatorsHolder).tm
 }
 
-// SetPropagators is the internal implementation for global.SetPropagators.
-func SetPropagators(pr propagation.Propagators) {
-	globalPropagators.Store(propagatorsHolder{pr: pr})
+// SetTextMapPropagator is the internal implementation for global.SetTextMapPropagator.
+func SetTextMapPropagator(p otel.TextMapPropagator) {
+	globalPropagators.Store(propagatorsHolder{tm: p})
 }
 
 func defaultTracerValue() *atomic.Value {
@@ -114,13 +114,14 @@ func defaultMeterValue() *atomic.Value {
 
 func defaultPropagatorsValue() *atomic.Value {
 	v := &atomic.Value{}
-	v.Store(propagatorsHolder{pr: getDefaultPropagators()})
+	v.Store(propagatorsHolder{tm: getDefaultTextMapPropagator()})
 	return v
 }
 
-// getDefaultPropagators returns a default noop Propagators
-func getDefaultPropagators() propagation.Propagators {
-	return propagation.New()
+// getDefaultTextMapPropagator returns the default TextMapPropagator,
+// configured with W3C trace and baggage propagation.
+func getDefaultTextMapPropagator() otel.TextMapPropagator {
+	return otel.NewCompositeTextMapPropagator()
 }
 
 // ResetForTest restores the initial global state, for testing purposes.

api/global/propagation.go

@@ -15,18 +15,17 @@
 package global
 
 import (
+	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/api/global/internal"
-	"go.opentelemetry.io/otel/api/propagation"
 )
 
-// Propagators returns the registered global propagators instance.  If
-// none is registered then an instance of propagators.NoopPropagators
-// is returned.
-func Propagators() propagation.Propagators {
-	return internal.Propagators()
+// TextMapPropagator returns the global TextMapPropagator. If none has been
+// set, a No-Op TextMapPropagator is returned.
+func TextMapPropagator() otel.TextMapPropagator {
+	return internal.TextMapPropagator()
 }
 
-// SetPropagators registers `p` as the global propagators instance.
-func SetPropagators(p propagation.Propagators) {
-	internal.SetPropagators(p)
+// SetTextMapPropagator sets propagator as the global TSetTextMapPropagator.
+func SetTextMapPropagator(propagator otel.TextMapPropagator) {
+	internal.SetTextMapPropagator(propagator)
 }