Begin adding entity exporter

entity/entity.go

@@ -15,9 +15,27 @@
 package entity // import "go.opentelemetry.io/otel/entity"
 
 import (
+	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/entity/embedded"
 )
 
+type Entity interface {
+	embedded.Entity
+
+	// IsRecording returns the recording state of the Span. It will return
+	// true if the Span is active and events can be recorded.
+	IsRecording() bool
+
+	// SetAttributes sets kv as attributes of the Span. If a key from kv
+	// already exists for an attribute of the Span it will be overwritten with
+	// the value contained in kv.
+	SetAttributes(kv ...attribute.KeyValue)
+
+	// TracerProvider returns a TracerProvider that can be used to generate
+	// additional Spans on the same telemetry pipeline as the current Span.
+	EntityEmitterProvider() EntityEmitterProvider
+}
+
 // EntityEmitter is the creator of Spans.
 //
 // Warning: Methods may be added to this interface in minor releases. See

exporters/otlp/otlpentity/clients.go

@@ -0,0 +1,54 @@
+// 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 otlpentity // import "go.opentelemetry.io/otel/exporters/otlp/otlpentity"
+
+import (
+	"context"
+
+	entitiespb "go.opentelemetry.io/proto/otlp/entities/v1"
+)
+
+// Client manages connections to the collector, handles the
+// transformation of data into wire format, and the transmission of that
+// data to the collector.
+type Client interface {
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Start should establish connection(s) to endpoint(s). It is
+	// called just once by the exporter, so the implementation
+	// does not need to worry about idempotence and locking.
+	Start(ctx context.Context) error
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Stop should close the connections. The function is called
+	// only once by the exporter, so the implementation does not
+	// need to worry about idempotence, but it may be called
+	// concurrently with UploadEntitys, so proper
+	// locking is required. The function serves as a
+	// synchronization point - after the function returns, the
+	// process of closing connections is assumed to be finished.
+	Stop(ctx context.Context) error
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// UploadEntitys should transform the passed entitys to the wire
+	// format and send it to the collector. May be called
+	// concurrently.
+	UploadEntities(ctx context.Context, entities []*entitiespb.ScopeEntities) error
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+}

exporters/otlp/otlpentity/exporter.go

@@ -0,0 +1,120 @@
+// 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 otlpentity // import "go.opentelemetry.io/otel/exporters/otlp/otlpentity"
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sync"
+
+	"go.opentelemetry.io/otel/exporters/otlp/otlpentity/internal/entitytransform"
+	"go.opentelemetry.io/otel/sdk/resource"
+)
+
+var errAlreadyStarted = errors.New("already started")
+
+// Exporter exports entity data in the OTLP wire format.
+type Exporter struct {
+	client Client
+
+	mu      sync.RWMutex
+	started bool
+
+	startOnce sync.Once
+	stopOnce  sync.Once
+}
+
+// ExportSpans exports a batch of spans.
+func (e *Exporter) ExportEntities(ctx context.Context, entities []resource.ReadOnlyEntity) error {
+	protoSpans := entitytransform.Entities(entities)
+	if len(protoSpans) == 0 {
+		return nil
+	}
+
+	err := e.client.UploadEntities(ctx, protoSpans)
+	if err != nil {
+		return fmt.Errorf("entitys export: %w", err)
+	}
+	return nil
+}
+
+// Start establishes a connection to the receiving endpoint.
+func (e *Exporter) Start(ctx context.Context) error {
+	err := errAlreadyStarted
+	e.startOnce.Do(
+		func() {
+			e.mu.Lock()
+			e.started = true
+			e.mu.Unlock()
+			err = e.client.Start(ctx)
+		},
+	)
+
+	return err
+}
+
+// Shutdown flushes all exports and closes all connections to the receiving endpoint.
+func (e *Exporter) Shutdown(ctx context.Context) error {
+	e.mu.RLock()
+	started := e.started
+	e.mu.RUnlock()
+
+	if !started {
+		return nil
+	}
+
+	var err error
+
+	e.stopOnce.Do(
+		func() {
+			err = e.client.Stop(ctx)
+			e.mu.Lock()
+			e.started = false
+			e.mu.Unlock()
+		},
+	)
+
+	return err
+}
+
+var _ resource.EntityExporter = (*Exporter)(nil)
+
+// New constructs a new Exporter and starts it.
+func New(ctx context.Context, client Client) (*Exporter, error) {
+	exp := NewUnstarted(client)
+	if err := exp.Start(ctx); err != nil {
+		return nil, err
+	}
+	return exp, nil
+}
+
+// NewUnstarted constructs a new Exporter and does not start it.
+func NewUnstarted(client Client) *Exporter {
+	return &Exporter{
+		client: client,
+	}
+}
+
+// MarshalLog is the marshaling function used by the logging system to represent this Exporter.
+func (e *Exporter) MarshalLog() interface{} {
+	return struct {
+		Type   string
+		Client Client
+	}{
+		Type:   "otlpentity",
+		Client: e.client,
+	}
+}

exporters/otlp/otlpentity/go.mod

@@ -0,0 +1,28 @@
+module go.opentelemetry.io/otel/exporters/otlp/otlpentity
+
+go 1.20
+
+require (
+	go.opentelemetry.io/otel v1.23.1
+	go.opentelemetry.io/otel/sdk v1.23.1
+	go.opentelemetry.io/proto/otlp v1.1.0
+)
+
+require (
+	github.com/go-logr/logr v1.4.1 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
+	go.opentelemetry.io/otel/metric v1.23.1 // indirect
+	go.opentelemetry.io/otel/trace v1.23.0-rc.1 // indirect
+	golang.org/x/sys v0.16.0 // indirect
+	google.golang.org/protobuf v1.32.0 // indirect
+)
+
+replace go.opentelemetry.io/otel => ../../..
+
+replace go.opentelemetry.io/otel/sdk => ../../../sdk
+
+replace go.opentelemetry.io/otel/trace => ../../../trace
+
+replace go.opentelemetry.io/otel/metric => ../../../metric
+
+replace go.opentelemetry.io/proto/otlp => ../../../../opentelemetry-proto-go/otlp/

exporters/otlp/otlpentity/go.sum

@@ -0,0 +1,14 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
+github.com/go-logr/logr v1.4.1 h1:pKouT5E8xu9zeFC39JXRDukb6JFQPXM5p5I91188VAQ=
+github.com/go-logr/logr v1.4.1/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
+github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
+github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+golang.org/x/sys v0.16.0 h1:xWw16ngr6ZMtmxDyKyIgsE93KNKz5HKmMa3b8ALHidU=
+golang.org/x/sys v0.16.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+google.golang.org/protobuf v1.32.0 h1:pPC6BG5ex8PDFnkbrGU3EixyhKcQ2aDuBS36lqK/C7I=
+google.golang.org/protobuf v1.32.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=