Move ReceiverFactory to "receiver" package (open-telemetry#86)

This is part 1 of 3 of the refactoring plan to eliminate factories.go
and move the content to corresponding packages (receiver, exporter, processor).

cmd/occollector/app/builder/exporters_builder.go

@@ -170,7 +170,7 @@ func (eb *ExportersBuilder) buildExporter(
 		// Traces data type is required. Create a trace exporter based on config.
 		tc, stopFunc, err := factory.CreateTraceExporter(eb.logger, config)
 		if err != nil {
-			if err == factories.ErrDataTypeIsNotSupported {
+			if err == models.ErrDataTypeIsNotSupported {
 				// Could not create because this exporter does not support this data type.
 				return nil, typeMismatchErr(config, requirement.requiredBy, models.TracesDataType)
 			}
@@ -185,7 +185,7 @@ func (eb *ExportersBuilder) buildExporter(
 		// Metrics data type is required. Create a trace exporter based on config.
 		mc, stopFunc, err := factory.CreateMetricsExporter(eb.logger, config)
 		if err != nil {
-			if err == factories.ErrDataTypeIsNotSupported {
+			if err == models.ErrDataTypeIsNotSupported {
 				// Could not create because this exporter does not support this data type.
 				return nil, typeMismatchErr(config, requirement.requiredBy, models.MetricsDataType)
 			}

cmd/occollector/app/builder/receivers_builder.go

@@ -21,7 +21,6 @@ import (
 	"go.uber.org/zap"
 
 	"github.com/open-telemetry/opentelemetry-service/consumer"
-	"github.com/open-telemetry/opentelemetry-service/factories"
 	"github.com/open-telemetry/opentelemetry-service/internal"
 	"github.com/open-telemetry/opentelemetry-service/models"
 	"github.com/open-telemetry/opentelemetry-service/processor/multiconsumer"
@@ -172,10 +171,10 @@ func (rb *ReceiversBuilder) findPipelinesToAttach(config models.Receiver) (attac
 }
 
 func (rb *ReceiversBuilder) attachReceiverToPipelines(
-	factory factories.ReceiverFactory,
+	factory receiver.Factory,
 	dataType models.DataType,
 	config models.Receiver,
-	receiver *builtReceiver,
+	rcv *builtReceiver,
 	pipelineProcessors []*builtProcessor,
 ) error {
 	// There are pipelines of the specified data type that must be attached to
@@ -188,15 +187,15 @@ func (rb *ReceiversBuilder) attachReceiverToPipelines(
 		junction := buildFanoutTraceConsumer(pipelineProcessors)
 
 		// Now create the receiver and tell it to send to the junction point.
-		receiver.trace, err = factory.CreateTraceReceiver(context.Background(), rb.logger, config, junction)
+		rcv.trace, err = factory.CreateTraceReceiver(context.Background(), rb.logger, config, junction)
 
 	case models.MetricsDataType:
 		junction := buildFanoutMetricConsumer(pipelineProcessors)
-		receiver.metrics, err = factory.CreateMetricsReceiver(rb.logger, config, junction)
+		rcv.metrics, err = factory.CreateMetricsReceiver(rb.logger, config, junction)
 	}
 
 	if err != nil {
-		if err == factories.ErrDataTypeIsNotSupported {
+		if err == models.ErrDataTypeIsNotSupported {
 			return fmt.Errorf(
 				"receiver %s does not support %s but it was used in a "+
 					"%s pipeline",
@@ -222,8 +221,8 @@ func (rb *ReceiversBuilder) buildReceiver(config models.Receiver) (*builtReceive
 	}
 
 	// Prepare to build the receiver.
-	factory := factories.GetReceiverFactory(config.Type())
-	receiver := &builtReceiver{}
+	factory := receiver.GetReceiverFactory(config.Type())
+	rcv := &builtReceiver{}
 
 	// Now we have list of pipelines broken down by data type. Iterate for each data type.
 	for dataType, pipelines := range pipelinesToAttach {
@@ -234,13 +233,13 @@ func (rb *ReceiversBuilder) buildReceiver(config models.Receiver) (*builtReceive
 
 		// Attach the corresponding part of the receiver to all pipelines that require
 		// this data type.
-		err := rb.attachReceiverToPipelines(factory, dataType, config, receiver, pipelines)
+		err := rb.attachReceiverToPipelines(factory, dataType, config, rcv, pipelines)
 		if err != nil {
 			return nil, err
 		}
 	}
 
-	return receiver, nil
+	return rcv, nil
 }
 
 func buildFanoutTraceConsumer(pipelineFrontProcessors []*builtProcessor) consumer.TraceConsumer {

configv2/configv2.go

@@ -26,6 +26,7 @@ import (
 
 	"github.com/open-telemetry/opentelemetry-service/factories"
 	"github.com/open-telemetry/opentelemetry-service/models"
+	"github.com/open-telemetry/opentelemetry-service/receiver"
 )
 
 // These are errors that can be returned by Load(). Note that error codes are not part
@@ -181,7 +182,7 @@ func loadReceivers(v *viper.Viper) (models.Receivers, error) {
 		}
 
 		// Find receiver factory based on "type" that we read from config source
-		factory := factories.GetReceiverFactory(typeStr)
+		factory := receiver.GetReceiverFactory(typeStr)
 		if factory == nil {
 			return nil, &configError{
 				code: errUnknownReceiverType,

configv2/example_factories.go

@@ -49,7 +49,7 @@ func (f *ExampleReceiverFactory) Type() string {
 }
 
 // CustomUnmarshaler returns nil because we don't need custom unmarshaling for this factory.
-func (f *ExampleReceiverFactory) CustomUnmarshaler() factories.CustomUnmarshaler {
+func (f *ExampleReceiverFactory) CustomUnmarshaler() receiver.CustomUnmarshaler {
 	return nil
 }
 
@@ -73,7 +73,7 @@ func (f *ExampleReceiverFactory) CreateTraceReceiver(
 	nextConsumer consumer.TraceConsumer,
 ) (receiver.TraceReceiver, error) {
 	if cfg.(*ExampleReceiver).FailTraceCreation {
-		return nil, factories.ErrDataTypeIsNotSupported
+		return nil, models.ErrDataTypeIsNotSupported
 	}
 	return &ExampleReceiverProducer{TraceConsumer: nextConsumer}, nil
 }
@@ -85,7 +85,7 @@ func (f *ExampleReceiverFactory) CreateMetricsReceiver(
 	nextConsumer consumer.MetricsConsumer,
 ) (receiver.MetricsReceiver, error) {
 	if cfg.(*ExampleReceiver).FailMetricsCreation {
-		return nil, factories.ErrDataTypeIsNotSupported
+		return nil, models.ErrDataTypeIsNotSupported
 	}
 	return &ExampleReceiverProducer{MetricsConsumer: nextConsumer}, nil
 }
@@ -181,7 +181,7 @@ func (f *MultiProtoReceiverFactory) Type() string {
 }
 
 // CustomUnmarshaler returns nil because we don't need custom unmarshaling for this factory.
-func (f *MultiProtoReceiverFactory) CustomUnmarshaler() factories.CustomUnmarshaler {
+func (f *MultiProtoReceiverFactory) CustomUnmarshaler() receiver.CustomUnmarshaler {
 	return nil
 }
 
@@ -311,7 +311,7 @@ func (f *ExampleProcessorFactory) CreateTraceProcessor(
 	nextConsumer consumer.TraceConsumer,
 	cfg models.Processor,
 ) (processor.TraceProcessor, error) {
-	return nil, factories.ErrDataTypeIsNotSupported
+	return nil, models.ErrDataTypeIsNotSupported
 }
 
 // CreateMetricsProcessor creates a metrics processor based on this config.
@@ -320,13 +320,13 @@ func (f *ExampleProcessorFactory) CreateMetricsProcessor(
 	nextConsumer consumer.MetricsConsumer,
 	cfg models.Processor,
 ) (processor.MetricsProcessor, error) {
-	return nil, factories.ErrDataTypeIsNotSupported
+	return nil, models.ErrDataTypeIsNotSupported
 }
 
 // RegisterTestFactories registers example factories. This is only used by tests.
 func RegisterTestFactories() error {
-	_ = factories.RegisterReceiverFactory(&ExampleReceiverFactory{})
-	_ = factories.RegisterReceiverFactory(&MultiProtoReceiverFactory{})
+	_ = receiver.RegisterReceiverFactory(&ExampleReceiverFactory{})
+	_ = receiver.RegisterReceiverFactory(&MultiProtoReceiverFactory{})
 	_ = factories.RegisterExporterFactory(&ExampleExporterFactory{})
 	_ = factories.RegisterProcessorFactory(&ExampleProcessorFactory{})
 	return nil

exporter/opencensusexporter/factory.go

@@ -150,5 +150,5 @@ func (f *exporterFactory) CreateTraceExporter(logger *zap.Logger, config models.
 
 // CreateMetricsExporter creates a metrics exporter based on this config.
 func (f *exporterFactory) CreateMetricsExporter(logger *zap.Logger, cfg models.Exporter) (consumer.MetricsConsumer, factories.StopFunc, error) {
-	return nil, nil, factories.ErrDataTypeIsNotSupported
+	return nil, nil, models.ErrDataTypeIsNotSupported
 }

exporter/opencensusexporter/factory_test.go

@@ -25,6 +25,7 @@ import (
 
 	"github.com/open-telemetry/opentelemetry-service/factories"
 	"github.com/open-telemetry/opentelemetry-service/internal/compression"
+	"github.com/open-telemetry/opentelemetry-service/models"
 )
 
 func TestCreateDefaultConfig(t *testing.T) {
@@ -40,7 +41,7 @@ func TestCreateMetricsExporter(t *testing.T) {
 	cfg := factory.CreateDefaultConfig()
 
 	_, _, err := factory.CreateMetricsExporter(zap.NewNop(), cfg)
-	assert.Error(t, err, factories.ErrDataTypeIsNotSupported)
+	assert.Error(t, err, models.ErrDataTypeIsNotSupported)
 }
 
 func TestCreateTraceExporter(t *testing.T) {

exporter/opencensusexporter/opencensusexporter_test.go

@@ -20,8 +20,9 @@ import (
 	"time"
 
 	"github.com/google/go-cmp/cmp"
-	"github.com/open-telemetry/opentelemetry-service/data"
 	"github.com/spf13/viper"
+
+	"github.com/open-telemetry/opentelemetry-service/data"
 )
 
 func TestOpenCensusTraceExportersFromViper(t *testing.T) {

factories/factories.go

@@ -15,75 +15,15 @@
 package factories
 
 import (
-	"context"
-	"errors"
 	"fmt"
 
-	"github.com/spf13/viper"
 	"go.uber.org/zap"
 
 	"github.com/open-telemetry/opentelemetry-service/consumer"
 	"github.com/open-telemetry/opentelemetry-service/models"
 	"github.com/open-telemetry/opentelemetry-service/processor"
-	"github.com/open-telemetry/opentelemetry-service/receiver"
 )
 
-///////////////////////////////////////////////////////////////////////////////
-// Receiver factory and its registry.
-
-// ReceiverFactory is factory interface for receivers.
-type ReceiverFactory interface {
-	// Type gets the type of the Receiver created by this factory.
-	Type() string
-
-	// CreateDefaultConfig creates the default configuration for the Receiver.
-	CreateDefaultConfig() models.Receiver
-
-	// CustomUnmarshaler returns a custom unmarshaler for the configuration or nil if
-	// there is no need for custom unmarshaling. This is typically used if viper.Unmarshal()
-	// is not sufficient to unmarshal correctly.
-	CustomUnmarshaler() CustomUnmarshaler
-
-	// CreateTraceReceiver creates a trace receiver based on this config.
-	// If the receiver type does not support tracing or if the config is not valid
-	// error will be returned instead.
-	CreateTraceReceiver(ctx context.Context, logger *zap.Logger, cfg models.Receiver,
-		nextConsumer consumer.TraceConsumer) (receiver.TraceReceiver, error)
-
-	// CreateMetricsReceiver creates a metrics receiver based on this config.
-	// If the receiver type does not support metrics or if the config is not valid
-	// error will be returned instead.
-	CreateMetricsReceiver(logger *zap.Logger, cfg models.Receiver,
-		consumer consumer.MetricsConsumer) (receiver.MetricsReceiver, error)
-}
-
-// ErrDataTypeIsNotSupported can be returned by CreateTraceReceiver or
-// CreateMetricsReceiver if the particular telemetry data type is not supported
-// by the receiver.
-var ErrDataTypeIsNotSupported = errors.New("telemetry type is not supported")
-
-// CustomUnmarshaler is a function that un-marshals a viper data into a config struct
-// in a custom way.
-type CustomUnmarshaler func(v *viper.Viper, viperKey string, intoCfg interface{}) error
-
-// List of registered receiver factories.
-var receiverFactories = make(map[string]ReceiverFactory)
-
-// RegisterReceiverFactory registers a receiver factory.
-func RegisterReceiverFactory(factory ReceiverFactory) error {
-	if receiverFactories[factory.Type()] != nil {
-		panic(fmt.Sprintf("duplicate receiver factory %q", factory.Type()))
-	}
-
-	receiverFactories[factory.Type()] = factory
-	return nil
-}
-
-// GetReceiverFactory gets a receiver factory by type string.
-func GetReceiverFactory(typeStr string) ReceiverFactory {
-	return receiverFactories[typeStr]
-}
-
 ///////////////////////////////////////////////////////////////////////////////
 // Exporter factory and its registry.
 

factories/factories_test.go

@@ -15,84 +15,15 @@
 package factories
 
 import (
-	"context"
 	"testing"
 
 	"go.uber.org/zap"
 
 	"github.com/open-telemetry/opentelemetry-service/consumer"
 	"github.com/open-telemetry/opentelemetry-service/models"
 	"github.com/open-telemetry/opentelemetry-service/processor"
-	"github.com/open-telemetry/opentelemetry-service/receiver"
 )
 
-type ExampleReceiverFactory struct {
-}
-
-// Type gets the type of the Receiver config created by this factory.
-func (f *ExampleReceiverFactory) Type() string {
-	return "examplereceiver"
-}
-
-// CustomUnmarshaler returns nil because we don't need custom unmarshaling for this factory.
-func (f *ExampleReceiverFactory) CustomUnmarshaler() CustomUnmarshaler {
-	return nil
-}
-
-// CreateDefaultConfig creates the default configuration for the Receiver.
-func (f *ExampleReceiverFactory) CreateDefaultConfig() models.Receiver {
-	return nil
-}
-
-// CreateTraceReceiver creates a trace receiver based on this config.
-func (f *ExampleReceiverFactory) CreateTraceReceiver(
-	ctx context.Context,
-	logger *zap.Logger,
-	cfg models.Receiver,
-	nextConsumer consumer.TraceConsumer,
-) (receiver.TraceReceiver, error) {
-	// Not used for this test, just return nil
-	return nil, nil
-}
-
-// CreateMetricsReceiver creates a metrics receiver based on this config.
-func (f *ExampleReceiverFactory) CreateMetricsReceiver(
-	logger *zap.Logger,
-	cfg models.Receiver,
-	consumer consumer.MetricsConsumer,
-) (receiver.MetricsReceiver, error) {
-	// Not used for this test, just return nil
-	return nil, nil
-}
-
-func TestRegisterReceiverFactory(t *testing.T) {
-	f := ExampleReceiverFactory{}
-	err := RegisterReceiverFactory(&f)
-	if err != nil {
-		t.Fatalf("cannot register factory")
-	}
-
-	if &f != GetReceiverFactory(f.Type()) {
-		t.Fatalf("cannot find factory")
-	}
-
-	// Verify that attempt to register a factory with duplicate name panics
-	panicked := false
-	func() {
-		defer func() {
-			if r := recover(); r != nil {
-				panicked = true
-			}
-		}()
-
-		err = RegisterReceiverFactory(&f)
-	}()
-
-	if !panicked {
-		t.Fatalf("must panic on double registration")
-	}
-}
-
 type ExampleExporterFactory struct {
 }
 
@@ -163,7 +94,7 @@ func (f *ExampleProcessorFactory) CreateTraceProcessor(
 	nextConsumer consumer.TraceConsumer,
 	cfg models.Processor,
 ) (processor.TraceProcessor, error) {
-	return nil, ErrDataTypeIsNotSupported
+	return nil, models.ErrDataTypeIsNotSupported
 }
 
 // CreateMetricsProcessor creates a metrics processor based on this config.
@@ -172,7 +103,7 @@ func (f *ExampleProcessorFactory) CreateMetricsProcessor(
 	nextConsumer consumer.MetricsConsumer,
 	cfg models.Processor,
 ) (processor.MetricsProcessor, error) {
-	return nil, ErrDataTypeIsNotSupported
+	return nil, models.ErrDataTypeIsNotSupported
 }
 
 func TestRegisterProcessorFactory(t *testing.T) {

internal/collector/processor/nodebatcher/factory.go

@@ -101,5 +101,5 @@ func (f *processorFactory) CreateMetricsProcessor(
 	nextConsumer consumer.MetricsConsumer,
 	cfg models.Processor,
 ) (processor.MetricsProcessor, error) {
-	return nil, factories.ErrDataTypeIsNotSupported
+	return nil, models.ErrDataTypeIsNotSupported
 }

internal/collector/processor/queued/factory.go

@@ -75,5 +75,5 @@ func (f *processorFactory) CreateMetricsProcessor(
 	nextConsumer consumer.MetricsConsumer,
 	cfg models.Processor,
 ) (processor.MetricsProcessor, error) {
-	return nil, factories.ErrDataTypeIsNotSupported
+	return nil, models.ErrDataTypeIsNotSupported
 }