Add extension factory helper similar with other components

exporter/exporterhelper/factory.go

@@ -39,7 +39,6 @@ type CreateMetricsExporter func(context.Context, component.ExporterCreateParams,
 // CreateMetricsExporter is the equivalent of component.ExporterFactory.CreateLogsExporter()
 type CreateLogsExporter func(context.Context, component.ExporterCreateParams, configmodels.Exporter) (component.LogsExporter, error)
 
-// factory is the factory for Jaeger gRPC exporter.
 type factory struct {
 	cfgType               configmodels.Type
 	customUnmarshaler     component.CustomUnmarshaler
@@ -72,14 +71,14 @@ func WithLogs(createLogsExporter CreateLogsExporter) FactoryOption {
 	}
 }
 
-// WithCustomUnmarshaler overrides the default "not available" CustomUnmarshaler.
+// WithCustomUnmarshaler implements component.ConfigUnmarshaler.
 func WithCustomUnmarshaler(customUnmarshaler component.CustomUnmarshaler) FactoryOption {
 	return func(o *factory) {
 		o.customUnmarshaler = customUnmarshaler
 	}
 }
 
-// NewFactory returns a component.ExporterFactory that only supports all types.
+// NewFactory returns a component.ExporterFactory.
 func NewFactory(
 	cfgType configmodels.Type,
 	createDefaultConfig CreateDefaultConfig,
@@ -150,8 +149,7 @@ type factoryWithUnmarshaler struct {
 	*factory
 }
 
-// CustomUnmarshaler returns a custom unmarshaler for the configuration or nil if
-// there is no need for custom unmarshaling.
+// 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.go

@@ -0,0 +1,99 @@
+// Copyright  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 extensionhelper
+
+import (
+	"context"
+
+	"github.com/spf13/viper"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/config/configmodels"
+)
+
+// FactoryOption apply changes to ExporterOptions.
+type FactoryOption func(o *factory)
+
+// CreateDefaultConfig is the equivalent of component.ExtensionFactory.CreateDefaultConfig()
+type CreateDefaultConfig func() configmodels.Extension
+
+// CreateTraceExtension is the equivalent of component.ExtensionFactory.CreateTraceExtension()
+type CreateServiceExtension func(context.Context, component.ExtensionCreateParams, configmodels.Extension) (component.ServiceExtension, error)
+
+type factory struct {
+	cfgType                configmodels.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 configmodels.Type,
+	createDefaultConfig CreateDefaultConfig,
+	createServiceExtension CreateServiceExtension,
+	options ...FactoryOption) component.ExtensionFactory {
+	f := &factory{
+		cfgType:                cfgType,
+		createDefaultConfig:    createDefaultConfig,
+		createServiceExtension: createServiceExtension,
+	}
+	for _, opt := range options {
+		opt(f)
+	}
+	var ret component.ExtensionFactory
+	if f.customUnmarshaler != nil {
+		ret = &factoryWithUnmarshaler{f}
+	} else {
+		ret = f
+	}
+	return ret
+}
+
+// Type gets the type of the Extension config created by this factory.
+func (f *factory) Type() configmodels.Type {
+	return f.cfgType
+}
+
+// CreateDefaultConfig creates the default configuration for processor.
+func (f *factory) CreateDefaultConfig() configmodels.Extension {
+	return f.createDefaultConfig()
+}
+
+// CreateExtension creates a component.TraceExtension based on this config.
+func (f *factory) CreateExtension(
+	ctx context.Context,
+	params component.ExtensionCreateParams,
+	cfg configmodels.Extension) (component.ServiceExtension, 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

@@ -0,0 +1,91 @@
+// Copyright  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 extensionhelper
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/assert"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/config/configmodels"
+)
+
+const typeStr = "test"
+
+var (
+	defaultCfg = &configmodels.ExtensionSettings{
+		TypeVal: typeStr,
+		NameVal: typeStr,
+	}
+	nopExtensionInstance = new(nopExtension)
+)
+
+func TestNewFactory(t *testing.T) {
+	factory := NewFactory(
+		typeStr,
+		defaultConfig,
+		createExtension)
+	assert.EqualValues(t, typeStr, factory.Type())
+	assert.EqualValues(t, defaultCfg, factory.CreateDefaultConfig())
+	ext, err := factory.CreateExtension(context.Background(), component.ExtensionCreateParams{}, defaultCfg)
+	assert.NoError(t, err)
+	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() configmodels.Extension {
+	return defaultCfg
+}
+
+func createExtension(context.Context, component.ExtensionCreateParams, configmodels.Extension) (component.ServiceExtension, error) {
+	return nopExtensionInstance, nil
+}
+
+func customUnmarshaler(*viper.Viper, interface{}) error {
+	return errors.New("my error")
+}
+
+type nopExtension struct {
+}
+
+func (ne *nopExtension) Start(context.Context, component.Host) error {
+	return nil
+}
+
+// Shutdown stops the exporter and is invoked during shutdown.
+func (ne *nopExtension) Shutdown(context.Context) error {
+	return nil
+}

extension/fluentbitextension/config_test.go

@@ -30,7 +30,7 @@ func TestLoadConfig(t *testing.T) {
 	factories, err := componenttest.ExampleComponents()
 	assert.NoError(t, err)
 
-	factory := &Factory{}
+	factory := NewFactory()
 	factories.Extensions[typeStr] = factory
 	cfg, err := configtest.LoadConfigFile(t, path.Join(".", "testdata", "config.yaml"), factories)
 

extension/fluentbitextension/factory.go

@@ -19,24 +19,23 @@ import (
 
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/config/configmodels"
+	"go.opentelemetry.io/collector/extension/extensionhelper"
 )
 
 const (
 	// The value of extension "type" in configuration.
 	typeStr = "fluentbit"
 )
 
-// ExtensionFactory is the factory for the extension.
-type Factory struct {
+// NewFactory creates a factory for FluentBit extension.
+func NewFactory() component.ExtensionFactory {
+	return extensionhelper.NewFactory(
+		typeStr,
+		createDefaultConfig,
+		createExtension)
 }
 
-// Type gets the type of the config created by this factory.
-func (f *Factory) Type() configmodels.Type {
-	return typeStr
-}
-
-// CreateDefaultConfig creates the default configuration for the extension.
-func (f *Factory) CreateDefaultConfig() configmodels.Extension {
+func createDefaultConfig() configmodels.Extension {
 	return &Config{
 		ExtensionSettings: configmodels.ExtensionSettings{
 			TypeVal: typeStr,
@@ -45,9 +44,7 @@ func (f *Factory) CreateDefaultConfig() configmodels.Extension {
 	}
 }
 
-// CreateExtension creates the extension based on this config.
-func (f *Factory) CreateExtension(_ context.Context, params component.ExtensionCreateParams, cfg configmodels.Extension) (component.ServiceExtension, error) {
+func createExtension(_ context.Context, params component.ExtensionCreateParams, cfg configmodels.Extension) (component.ServiceExtension, error) {
 	config := cfg.(*Config)
-
 	return newProcessManager(config, params.Logger), nil
 }

extension/fluentbitextension/factory_test.go

@@ -27,14 +27,8 @@ import (
 	"go.opentelemetry.io/collector/config/configmodels"
 )
 
-func TestFactory_Type(t *testing.T) {
-	factory := Factory{}
-	require.Equal(t, configmodels.Type(typeStr), factory.Type())
-}
-
 func TestFactory_CreateDefaultConfig(t *testing.T) {
-	factory := Factory{}
-	cfg := factory.CreateDefaultConfig()
+	cfg := createDefaultConfig()
 	assert.Equal(t, &Config{
 		ExtensionSettings: configmodels.ExtensionSettings{
 			NameVal: typeStr,
@@ -44,16 +38,14 @@ func TestFactory_CreateDefaultConfig(t *testing.T) {
 		cfg)
 
 	assert.NoError(t, configcheck.ValidateConfig(cfg))
-	ext, err := factory.CreateExtension(context.Background(), component.ExtensionCreateParams{Logger: zap.NewNop()}, cfg)
+	ext, err := createExtension(context.Background(), component.ExtensionCreateParams{Logger: zap.NewNop()}, cfg)
 	require.NoError(t, err)
 	require.NotNil(t, ext)
 }
 
 func TestFactory_CreateExtension(t *testing.T) {
-	factory := Factory{}
-	cfg := factory.CreateDefaultConfig().(*Config)
-
-	ext, err := factory.CreateExtension(context.Background(), component.ExtensionCreateParams{Logger: zap.NewNop()}, cfg)
+	cfg := createDefaultConfig().(*Config)
+	ext, err := createExtension(context.Background(), component.ExtensionCreateParams{Logger: zap.NewNop()}, cfg)
 	require.NoError(t, err)
 	require.NotNil(t, ext)
 }

extension/healthcheckextension/config_test.go

@@ -30,7 +30,7 @@ func TestLoadConfig(t *testing.T) {
 	factories, err := componenttest.ExampleComponents()
 	assert.NoError(t, err)
 
-	factory := &Factory{}
+	factory := NewFactory()
 	factories.Extensions[typeStr] = factory
 	cfg, err := configtest.LoadConfigFile(t, path.Join(".", "testdata", "config.yaml"), factories)
 

extension/healthcheckextension/factory.go

@@ -21,24 +21,23 @@ import (
 
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/config/configmodels"
+	"go.opentelemetry.io/collector/extension/extensionhelper"
 )
 
 const (
 	// The value of extension "type" in configuration.
 	typeStr = "health_check"
 )
 
-// ExtensionFactory is the factory for the extension.
-type Factory struct {
+// NewFactory creates a factory for HealthCheck extension.
+func NewFactory() component.ExtensionFactory {
+	return extensionhelper.NewFactory(
+		typeStr,
+		createDefaultConfig,
+		createExtension)
 }
 
-// Type gets the type of the config created by this factory.
-func (f *Factory) Type() configmodels.Type {
-	return typeStr
-}
-
-// CreateDefaultConfig creates the default configuration for the extension.
-func (f *Factory) CreateDefaultConfig() configmodels.Extension {
+func createDefaultConfig() configmodels.Extension {
 	return &Config{
 		ExtensionSettings: configmodels.ExtensionSettings{
 			TypeVal: typeStr,
@@ -48,8 +47,7 @@ func (f *Factory) CreateDefaultConfig() configmodels.Extension {
 	}
 }
 
-// CreateExtension creates the extension based on this config.
-func (f *Factory) CreateExtension(_ context.Context, params component.ExtensionCreateParams, cfg configmodels.Extension) (component.ServiceExtension, error) {
+func createExtension(_ context.Context, params component.ExtensionCreateParams, cfg configmodels.Extension) (component.ServiceExtension, error) {
 	config := cfg.(*Config)
 
 	// The runtime settings are global to the application, so while in principle it