bridge/opentracing: introduce NewTracerProvider that wraps TracerProvider instead of Tracer (#3116)

* bridge/opentracing: add NewDynamicWrappedTracerProvider for named tracers

* bridge/opentelmeetry: cache created Tracers, add tests

* bridge/opentracing: rename constructor to NewTracerProvider

* add license header

* Update docstring

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

* fix deprecated docstring

* rewrite new lookup TracerProvider as separate type

* update docstring

* add changelog entries

* Update bridge/opentracing/provider.go

Co-authored-by: Damien Mathieu <42@dmathieu.com>

Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>
Co-authored-by: Damien Mathieu <42@dmathieu.com>

CHANGELOG.md

@@ -49,6 +49,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
   - `Int64Counter` replaces the `syncint64.Counter`
   - `Int64UpDownCounter` replaces the `syncint64.UpDownCounter`
   - `Int64Histogram` replaces the `syncint64.Histogram`
+- Add `NewTracerProvider` to `go.opentelemetry.io/otel/bridge/opentracing` to create `WrapperTracer` instances from a `TracerProvider`. (#3316)
 
 ### Changed
 
@@ -111,6 +112,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
   Use the instruments from `go.opentelemetry.io/otel/metric/instrument` instead. (#3575)
 - The `go.opentelemetry.io/otel/metric/instrument/syncint64` package is deprecated.
   Use the instruments from `go.opentelemetry.io/otel/metric/instrument` instead. (#3575)
+- The `NewWrappedTracerProvider` in `go.opentelemetry.io/otel/bridge/opentracing` is now deprecated. Use `NewTracerProvider` instead. (#3316)
 
 ### Removed
 

bridge/opentracing/provider.go

@@ -0,0 +1,71 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package opentracing // import "go.opentelemetry.io/otel/bridge/opentracing"
+
+import (
+	"sync"
+
+	"go.opentelemetry.io/otel/trace"
+)
+
+// TracerProvider is an OpenTelemetry TracerProvider that wraps an OpenTracing
+// Tracer.
+type TracerProvider struct {
+	bridge   *BridgeTracer
+	provider trace.TracerProvider
+
+	tracers map[wrappedTracerKey]*WrapperTracer
+	mtx     sync.Mutex
+}
+
+var _ trace.TracerProvider = (*TracerProvider)(nil)
+
+// NewTracerProvider returns a new TracerProvider that creates new instances of
+// WrapperTracer from the given TracerProvider.
+func NewTracerProvider(bridge *BridgeTracer, provider trace.TracerProvider) *TracerProvider {
+	return &TracerProvider{
+		bridge:   bridge,
+		provider: provider,
+
+		tracers: make(map[wrappedTracerKey]*WrapperTracer),
+	}
+}
+
+type wrappedTracerKey struct {
+	name    string
+	version string
+}
+
+// Tracer creates a WrappedTracer that wraps the OpenTelemetry tracer for each call to
+// Tracer(). Repeated calls to Tracer() with the same configuration will look up and
+// return an existing instance of WrapperTracer.
+func (p *TracerProvider) Tracer(name string, opts ...trace.TracerOption) trace.Tracer {
+	p.mtx.Lock()
+	defer p.mtx.Unlock()
+
+	c := trace.NewTracerConfig(opts...)
+	key := wrappedTracerKey{
+		name:    name,
+		version: c.InstrumentationVersion(),
+	}
+
+	if t, ok := p.tracers[key]; ok {
+		return t
+	}
+
+	wrapper := NewWrapperTracer(p.bridge, p.provider.Tracer(name, opts...))
+	p.tracers[key] = wrapper
+	return wrapper
+}

bridge/opentracing/provider_test.go

@@ -0,0 +1,85 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package opentracing
+
+import (
+	"testing"
+
+	"go.opentelemetry.io/otel/bridge/opentracing/internal"
+	"go.opentelemetry.io/otel/trace"
+)
+
+type namedMockTracer struct {
+	name string
+	*internal.MockTracer
+}
+
+type namedMockTracerProvider struct{}
+
+var _ trace.TracerProvider = (*namedMockTracerProvider)(nil)
+
+// Tracer returns the WrapperTracer associated with the WrapperTracerProvider.
+func (p *namedMockTracerProvider) Tracer(name string, opts ...trace.TracerOption) trace.Tracer {
+	return &namedMockTracer{
+		name:       name,
+		MockTracer: internal.NewMockTracer(),
+	}
+}
+
+func TestTracerProvider(t *testing.T) {
+	// assertMockTracerName casts tracer into a named mock tracer provided by
+	// namedMockTracerProvider, and asserts against its name
+	assertMockTracerName := func(t *testing.T, tracer trace.Tracer, name string) {
+		// Unwrap the tracer
+		wrapped := tracer.(*WrapperTracer)
+		tracer = wrapped.tracer
+
+		// Cast into the underlying type and assert
+		if mock, ok := tracer.(*namedMockTracer); ok {
+			if name != mock.name {
+				t.Errorf("expected name %q, got %q", name, mock.name)
+			}
+		} else if !ok {
+			t.Errorf("expected *namedMockTracer, got %T", mock)
+		}
+	}
+
+	var (
+		foobar   = "foobar"
+		bazbar   = "bazbar"
+		provider = NewTracerProvider(nil, &namedMockTracerProvider{})
+	)
+
+	t.Run("Tracers should be created with foobar from provider", func(t *testing.T) {
+		tracer := provider.Tracer(foobar)
+		assertMockTracerName(t, tracer, foobar)
+	})
+
+	t.Run("Repeated requests to create a tracer should provide the existing tracer", func(t *testing.T) {
+		tracer1 := provider.Tracer(foobar)
+		assertMockTracerName(t, tracer1, foobar)
+		tracer2 := provider.Tracer(foobar)
+		assertMockTracerName(t, tracer2, foobar)
+		tracer3 := provider.Tracer(bazbar)
+		assertMockTracerName(t, tracer3, bazbar)
+
+		if tracer1 != tracer2 {
+			t.Errorf("expected the same tracer, got different tracers")
+		}
+		if tracer1 == tracer3 || tracer2 == tracer3 {
+			t.Errorf("expected different tracers, got the same tracer")
+		}
+	})
+}

bridge/opentracing/wrapper.go

@@ -22,7 +22,9 @@ import (
 )
 
 // WrapperTracerProvider is an OpenTelemetry TracerProvider that wraps an
-// OpenTracing Tracer.
+// OpenTracing Tracer, created by the deprecated NewWrappedTracerProvider.
+//
+// Deprecated: Use the TracerProvider from NewTracerProvider(...) instead.
 type WrapperTracerProvider struct {
 	wTracer *WrapperTracer
 }
@@ -35,7 +37,10 @@ func (p *WrapperTracerProvider) Tracer(_ string, _ ...trace.TracerOption) trace.
 }
 
 // NewWrappedTracerProvider creates a new trace provider that creates a single
-// instance of WrapperTracer that wraps OpenTelemetry tracer.
+// instance of WrapperTracer that wraps OpenTelemetry tracer, and always returns
+// it unmodified from Tracer().
+//
+// Deprecated: Use NewTracerProvider(...) instead.
 func NewWrappedTracerProvider(bridge *BridgeTracer, tracer trace.Tracer) *WrapperTracerProvider {
 	return &WrapperTracerProvider{
 		wTracer: NewWrapperTracer(bridge, tracer),