Move Unmarshaler interface to Config instead of Factory

component/component.go

@@ -17,8 +17,6 @@ package component
 import (
 	"context"
 
-	"github.com/spf13/viper"
-
 	"go.opentelemetry.io/collector/config"
 )
 
@@ -78,22 +76,3 @@ type Factory interface {
 	// Type gets the type of the component created by this factory.
 	Type() config.Type
 }
-
-// ConfigUnmarshaler interface is an optional interface that if implemented by a Factory,
-// the configuration loading system will use to unmarshal the config.
-type ConfigUnmarshaler interface {
-	// Unmarshal is a function that un-marshals a viper data into a config struct in a custom way.
-	// componentViperSection *viper.Viper
-	//   The config for this specific component. May be nil or empty if no config available.
-	// intoCfg interface{}
-	//   An empty interface wrapping a pointer to the config struct to unmarshal into.
-	Unmarshal(componentViperSection *viper.Viper, intoCfg interface{}) error
-}
-
-// CustomUnmarshaler is a function that un-marshals a viper data into a config struct
-// in a custom way.
-// componentViperSection *viper.Viper
-//   The config for this specific component. May be nil or empty if no config available.
-// intoCfg interface{}
-//   An empty interface wrapping a pointer to the config struct to unmarshal into.
-type CustomUnmarshaler func(componentViperSection *viper.Viper, intoCfg interface{}) error

config/config.go

@@ -32,6 +32,8 @@ package config
 import (
 	"errors"
 	"fmt"
+
+	"github.com/spf13/viper"
 )
 
 var (
@@ -168,6 +170,14 @@ type validatable interface {
 	Validate() error
 }
 
+// Unmarshable defines the interface for the configuration unmarshaling.
+type Unmarshable interface {
+	// Unmarshal is a function that un-marshals a viper data into the Unmarshable struct in a custom way.
+	// componentViperSection *viper.Viper
+	//   The config for this specific component. May be nil or empty if no config available.
+	Unmarshal(componentViperSection *viper.Viper) error
+}
+
 // DataType is the data type that is supported for collection. We currently support
 // collecting metrics, traces and logs, this can expand in the future.
 type DataType string

config/configparser/config.go

@@ -245,8 +245,7 @@ func loadExtensions(exts map[string]interface{}, factories map[config.Type]compo
 
 		// Now that the default config struct is created we can Unmarshal into it
 		// and it will apply user-defined config on top of the default.
-		unm := unmarshaler(factory)
-		if err := unm(componentConfig, extensionCfg); err != nil {
+		if err := unmarshal(componentConfig, extensionCfg); err != nil {
 			return nil, errorUnmarshalError(extensionsKeyName, fullName, err)
 		}
 
@@ -281,8 +280,7 @@ func LoadReceiver(componentConfig *config.Parser, fullName string, factory compo
 
 	// Now that the default config struct is created we can Unmarshal into it
 	// and it will apply user-defined config on top of the default.
-	unm := unmarshaler(factory)
-	if err := unm(componentConfig, receiverCfg); err != nil {
+	if err := unmarshal(componentConfig, receiverCfg); err != nil {
 		return nil, errorUnmarshalError(receiversKeyName, fullName, err)
 	}
 
@@ -354,8 +352,7 @@ func loadExporters(exps map[string]interface{}, factories map[config.Type]compon
 
 		// Now that the default config struct is created we can Unmarshal into it
 		// and it will apply user-defined config on top of the default.
-		unm := unmarshaler(factory)
-		if err := unm(componentConfig, exporterCfg); err != nil {
+		if err := unmarshal(componentConfig, exporterCfg); err != nil {
 			return nil, errorUnmarshalError(exportersKeyName, fullName, err)
 		}
 
@@ -397,8 +394,7 @@ func loadProcessors(procs map[string]interface{}, factories map[config.Type]comp
 
 		// Now that the default config struct is created we can Unmarshal into it
 		// and it will apply user-defined config on top of the default.
-		unm := unmarshaler(factory)
-		if err := unm(componentConfig, processorCfg); err != nil {
+		if err := unmarshal(componentConfig, processorCfg); err != nil {
 			return nil, errorUnmarshalError(processorsKeyName, fullName, err)
 		}
 
@@ -533,15 +529,10 @@ func expandEnv(s string) string {
 	})
 }
 
-func unmarshaler(factory component.Factory) func(componentViperSection *config.Parser, intoCfg interface{}) error {
-	if fu, ok := factory.(component.ConfigUnmarshaler); ok {
-		return func(componentParser *config.Parser, intoCfg interface{}) error {
-			return fu.Unmarshal(componentParser.Viper(), intoCfg)
-		}
+func unmarshal(componentSection *config.Parser, intoCfg interface{}) error {
+	if cu, ok := intoCfg.(config.Unmarshable); ok {
+		return cu.Unmarshal(componentSection.Viper())
 	}
-	return defaultUnmarshaler
-}
 
-func defaultUnmarshaler(componentParser *config.Parser, intoCfg interface{}) error {
-	return componentParser.UnmarshalExact(intoCfg)
+	return componentSection.UnmarshalExact(intoCfg)
 }

exporter/exporterhelper/factory.go

@@ -17,8 +17,6 @@ package exporterhelper
 import (
 	"context"
 
-	"github.com/spf13/viper"
-
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/config"
 	"go.opentelemetry.io/collector/config/configerror"
@@ -41,7 +39,6 @@ type CreateLogsExporter func(context.Context, component.ExporterCreateParams, co
 
 type factory struct {
 	cfgType               config.Type
-	customUnmarshaler     component.CustomUnmarshaler
 	createDefaultConfig   CreateDefaultConfig
 	createTracesExporter  CreateTracesExporter
 	createMetricsExporter CreateMetricsExporter
@@ -69,13 +66,6 @@ func WithLogs(createLogsExporter CreateLogsExporter) FactoryOption {
 	}
 }
 
-// WithCustomUnmarshaler implements component.ConfigUnmarshaler.
-func WithCustomUnmarshaler(customUnmarshaler component.CustomUnmarshaler) FactoryOption {
-	return func(o *factory) {
-		o.customUnmarshaler = customUnmarshaler
-	}
-}
-
 // NewFactory returns a component.ExporterFactory.
 func NewFactory(
 	cfgType config.Type,
@@ -88,13 +78,7 @@ func NewFactory(
 	for _, opt := range options {
 		opt(f)
 	}
-	var ret component.ExporterFactory
-	if f.customUnmarshaler != nil {
-		ret = &factoryWithUnmarshaler{f}
-	} else {
-		ret = f
-	}
-	return ret
+	return f
 }
 
 // Type gets the type of the Exporter config created by this factory.
@@ -140,14 +124,3 @@ func (f *factory) CreateLogsExporter(
 	}
 	return nil, configerror.ErrDataTypeIsNotSupported
 }
-
-var _ component.ConfigUnmarshaler = (*factoryWithUnmarshaler)(nil)
-
-type factoryWithUnmarshaler struct {
-	*factory
-}
-
-// Unmarshal un-marshals the config using the provided custom unmarshaler.
-func (f *factoryWithUnmarshaler) Unmarshal(componentViperSection *viper.Viper, intoCfg interface{}) error {
-	return f.customUnmarshaler(componentViperSection, intoCfg)
-}

exporter/exporterhelper/factory_test.go

@@ -16,10 +16,8 @@ package exporterhelper
 
 import (
 	"context"
-	"errors"
 	"testing"
 
-	"github.com/spf13/viper"
 	"github.com/stretchr/testify/assert"
 	"go.uber.org/zap"
 
@@ -53,8 +51,6 @@ func TestNewFactory(t *testing.T) {
 		defaultConfig)
 	assert.EqualValues(t, typeStr, factory.Type())
 	assert.EqualValues(t, defaultCfg, factory.CreateDefaultConfig())
-	_, ok := factory.(component.ConfigUnmarshaler)
-	assert.False(t, ok)
 	_, err := factory.CreateTracesExporter(context.Background(), component.ExporterCreateParams{Logger: zap.NewNop()}, defaultCfg)
 	assert.Equal(t, configerror.ErrDataTypeIsNotSupported, err)
 	_, err = factory.CreateMetricsExporter(context.Background(), component.ExporterCreateParams{Logger: zap.NewNop()}, defaultCfg)
@@ -69,15 +65,10 @@ func TestNewFactory_WithConstructors(t *testing.T) {
 		defaultConfig,
 		WithTraces(createTraceExporter),
 		WithMetrics(createMetricsExporter),
-		WithLogs(createLogsExporter),
-		WithCustomUnmarshaler(customUnmarshaler))
+		WithLogs(createLogsExporter))
 	assert.EqualValues(t, typeStr, factory.Type())
 	assert.EqualValues(t, defaultCfg, factory.CreateDefaultConfig())
 
-	fu, ok := factory.(component.ConfigUnmarshaler)
-	assert.True(t, ok)
-	assert.Equal(t, errors.New("my error"), fu.Unmarshal(nil, nil))
-
 	te, err := factory.CreateTracesExporter(context.Background(), component.ExporterCreateParams{Logger: zap.NewNop()}, defaultCfg)
 	assert.NoError(t, err)
 	assert.Same(t, nopTracesExporter, te)
@@ -106,7 +97,3 @@ func createMetricsExporter(context.Context, component.ExporterCreateParams, conf
 func createLogsExporter(context.Context, component.ExporterCreateParams, config.Exporter) (component.LogsExporter, error) {
 	return nopLogsExporter, nil
 }
-
-func customUnmarshaler(*viper.Viper, interface{}) error {
-	return errors.New("my error")
-}

extension/extensionhelper/factory.go

@@ -17,8 +17,6 @@ package extensionhelper
 import (
 	"context"
 
-	"github.com/spf13/viper"
-
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/config"
 )
@@ -34,18 +32,10 @@ type CreateServiceExtension func(context.Context, component.ExtensionCreateParam
 
 type factory struct {
 	cfgType                config.Type
-	customUnmarshaler      component.CustomUnmarshaler
 	createDefaultConfig    CreateDefaultConfig
 	createServiceExtension CreateServiceExtension
 }
 
-// WithCustomUnmarshaler implements component.ConfigUnmarshaler.
-func WithCustomUnmarshaler(customUnmarshaler component.CustomUnmarshaler) FactoryOption {
-	return func(o *factory) {
-		o.customUnmarshaler = customUnmarshaler
-	}
-}
-
 // NewFactory returns a component.ExtensionFactory.
 func NewFactory(
 	cfgType config.Type,
@@ -60,13 +50,7 @@ func NewFactory(
 	for _, opt := range options {
 		opt(f)
 	}
-	var ret component.ExtensionFactory
-	if f.customUnmarshaler != nil {
-		ret = &factoryWithUnmarshaler{f}
-	} else {
-		ret = f
-	}
-	return ret
+	return f
 }
 
 // Type gets the type of the Extension config created by this factory.
@@ -86,14 +70,3 @@ func (f *factory) CreateExtension(
 	cfg config.Extension) (component.Extension, error) {
 	return f.createServiceExtension(ctx, params, cfg)
 }
-
-var _ component.ConfigUnmarshaler = (*factoryWithUnmarshaler)(nil)
-
-type factoryWithUnmarshaler struct {
-	*factory
-}
-
-// Unmarshal un-marshals the config using the provided custom unmarshaler.
-func (f *factoryWithUnmarshaler) Unmarshal(componentViperSection *viper.Viper, intoCfg interface{}) error {
-	return f.customUnmarshaler(componentViperSection, intoCfg)
-}

extension/extensionhelper/factory_test.go

@@ -16,10 +16,8 @@ package extensionhelper
 
 import (
 	"context"
-	"errors"
 	"testing"
 
-	"github.com/spf13/viper"
 	"github.com/stretchr/testify/assert"
 
 	"go.opentelemetry.io/collector/component"
@@ -48,24 +46,6 @@ func TestNewFactory(t *testing.T) {
 	assert.Same(t, nopExtensionInstance, ext)
 }
 
-func TestNewFactory_WithConstructors(t *testing.T) {
-	factory := NewFactory(
-		typeStr,
-		defaultConfig,
-		createExtension,
-		WithCustomUnmarshaler(customUnmarshaler))
-	assert.EqualValues(t, typeStr, factory.Type())
-	assert.EqualValues(t, defaultCfg, factory.CreateDefaultConfig())
-
-	fu, ok := factory.(component.ConfigUnmarshaler)
-	assert.True(t, ok)
-	assert.Equal(t, errors.New("my error"), fu.Unmarshal(nil, nil))
-
-	ext, err := factory.CreateExtension(context.Background(), component.ExtensionCreateParams{}, defaultCfg)
-	assert.NoError(t, err)
-	assert.Same(t, nopExtensionInstance, ext)
-}
-
 func defaultConfig() config.Extension {
 	return defaultCfg
 }
@@ -74,10 +54,6 @@ func createExtension(context.Context, component.ExtensionCreateParams, config.Ex
 	return nopExtensionInstance, nil
 }
 
-func customUnmarshaler(*viper.Viper, interface{}) error {
-	return errors.New("my error")
-}
-
 type nopExtension struct {
 }
 

internal/testcomponents/example_exporter.go

@@ -25,6 +25,8 @@ import (
 	"go.opentelemetry.io/collector/exporter/exporterhelper"
 )
 
+var _ config.Unmarshable = (*ExampleExporter)(nil)
+
 // ExampleExporter is for testing purposes. We are defining an example config and factory
 // for "exampleexporter" exporter type.
 type ExampleExporter struct {
@@ -35,13 +37,17 @@ type ExampleExporter struct {
 	ExtraListSetting        []string                 `mapstructure:"extra_list"`
 }
 
+// Unmarshal a viper data into the config struct
+func (cfg *ExampleExporter) Unmarshal(componentViperSection *viper.Viper) error {
+	return componentViperSection.UnmarshalExact(cfg)
+}
+
 const expType = "exampleexporter"
 
 // ExampleExporterFactory is factory for ExampleExporter.
 var ExampleExporterFactory = exporterhelper.NewFactory(
 	expType,
 	createExporterDefaultConfig,
-	exporterhelper.WithCustomUnmarshaler(customUnmarshal),
 	exporterhelper.WithTraces(createTracesExporter),
 	exporterhelper.WithMetrics(createMetricsExporter),
 	exporterhelper.WithLogs(createLogsExporter))
@@ -59,10 +65,6 @@ func createExporterDefaultConfig() config.Exporter {
 	}
 }
 
-func customUnmarshal(componentViperSection *viper.Viper, intoCfg interface{}) error {
-	return componentViperSection.UnmarshalExact(intoCfg)
-}
-
 func createTracesExporter(
 	_ context.Context,
 	_ component.ExporterCreateParams,