Remove BaseProcessorFactory, force using helper (open-telemetry#4175)

* Add internalinterface package

This adds a general InternalInterface to make an interface impossible
to implement.

* Use internalinterface.InternalInterface for Processor as a test

* Add Changelog note

* need to use -> must use

* Add small unit test

Co-authored-by: Bogdan Drutu <[email protected]>

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ## 🛑 Breaking changes 🛑
 
+- Remove `component.BaseProcessorFactory`, use `processorhelper.NewFactory` instead (#4175)
 - Move `service/parserprovider` package to `config/configmapprovider` (#4206)
 
 ## v0.38.0 Beta

component/componenttest/nop_processor.go

@@ -22,6 +22,7 @@ import (
 	"go.opentelemetry.io/collector/config"
 	"go.opentelemetry.io/collector/consumer"
 	"go.opentelemetry.io/collector/consumer/consumertest"
+	"go.opentelemetry.io/collector/internal/internalinterface"
 )
 
 // NewNopProcessorCreateSettings returns a new nop settings for Create*Processor functions.
@@ -38,7 +39,7 @@ type nopProcessorConfig struct {
 
 // nopProcessorFactory is factory for nopProcessor.
 type nopProcessorFactory struct {
-	component.BaseProcessorFactory
+	internalinterface.BaseInternal
 }
 
 var nopProcessorFactoryInstance = &nopProcessorFactory{}

component/processor.go

@@ -17,9 +17,9 @@ package component // import "go.opentelemetry.io/collector/component"
 import (
 	"context"
 
-	"go.opentelemetry.io/collector/component/componenterror"
 	"go.opentelemetry.io/collector/config"
 	"go.opentelemetry.io/collector/consumer"
+	"go.opentelemetry.io/collector/internal/internalinterface"
 )
 
 // Processor defines the common functions that must be implemented by TracesProcessor
@@ -57,9 +57,10 @@ type ProcessorCreateSettings struct {
 // ProcessorFactory is factory interface for processors. This is the
 // new factory type that can create new style processors.
 //
-// This interface cannot be directly implemented. Implementations need to embed
-// the BaseProcessorFactory or use the processorhelper.NewFactory to implement it.
+// This interface cannot be directly implemented. Implementations must
+// use the processorhelper.NewFactory to implement it.
 type ProcessorFactory interface {
+	internalinterface.InternalInterface
 	Factory
 
 	// CreateDefaultConfig creates the default configuration for the Processor.
@@ -100,39 +101,4 @@ type ProcessorFactory interface {
 		cfg config.Processor,
 		nextConsumer consumer.Logs,
 	) (LogsProcessor, error)
-
-	// unexportedProcessor is a dummy method to force this interface to not be implemented.
-	unexportedProcessor()
-}
-
-// BaseProcessorFactory is the interface that must be embedded by all ProcessorFactory implementations.
-type BaseProcessorFactory struct{}
-
-var _ ProcessorFactory = (*BaseProcessorFactory)(nil)
-
-// Type must be overridden.
-func (b BaseProcessorFactory) Type() config.Type {
-	panic("implement me")
-}
-
-// CreateDefaultConfig must be overridden.
-func (b BaseProcessorFactory) CreateDefaultConfig() config.Processor {
-	panic("implement me")
 }
-
-// CreateTracesProcessor default implemented as not supported data type.
-func (b BaseProcessorFactory) CreateTracesProcessor(context.Context, ProcessorCreateSettings, config.Processor, consumer.Traces) (TracesProcessor, error) {
-	return nil, componenterror.ErrDataTypeIsNotSupported
-}
-
-// CreateMetricsProcessor default implemented as not supported data type.
-func (b BaseProcessorFactory) CreateMetricsProcessor(context.Context, ProcessorCreateSettings, config.Processor, consumer.Metrics) (MetricsProcessor, error) {
-	return nil, componenterror.ErrDataTypeIsNotSupported
-}
-
-// CreateLogsProcessor default implemented as not supported data type.
-func (b BaseProcessorFactory) CreateLogsProcessor(context.Context, ProcessorCreateSettings, config.Processor, consumer.Logs) (LogsProcessor, error) {
-	return nil, componenterror.ErrDataTypeIsNotSupported
-}
-
-func (b BaseProcessorFactory) unexportedProcessor() {}

component/processor_test.go

@@ -22,11 +22,14 @@ import (
 
 	"go.opentelemetry.io/collector/component/componenterror"
 	"go.opentelemetry.io/collector/config"
-	"go.opentelemetry.io/collector/consumer/consumertest"
+	"go.opentelemetry.io/collector/consumer"
+	"go.opentelemetry.io/collector/internal/internalinterface"
 )
 
+var _ ProcessorFactory = (*TestProcessorFactory)(nil)
+
 type TestProcessorFactory struct {
-	BaseProcessorFactory
+	internalinterface.BaseInternal
 	name string
 }
 
@@ -40,6 +43,21 @@ func (f *TestProcessorFactory) CreateDefaultConfig() config.Processor {
 	return nil
 }
 
+// CreateTracesProcessor default implemented as not supported data type.
+func (f *TestProcessorFactory) CreateTracesProcessor(context.Context, ProcessorCreateSettings, config.Processor, consumer.Traces) (TracesProcessor, error) {
+	return nil, componenterror.ErrDataTypeIsNotSupported
+}
+
+// CreateMetricsProcessor default implemented as not supported data type.
+func (f *TestProcessorFactory) CreateMetricsProcessor(context.Context, ProcessorCreateSettings, config.Processor, consumer.Metrics) (MetricsProcessor, error) {
+	return nil, componenterror.ErrDataTypeIsNotSupported
+}
+
+// CreateLogsProcessor default implemented as not supported data type.
+func (f *TestProcessorFactory) CreateLogsProcessor(context.Context, ProcessorCreateSettings, config.Processor, consumer.Logs) (LogsProcessor, error) {
+	return nil, componenterror.ErrDataTypeIsNotSupported
+}
+
 func TestMakeProcessorFactoryMap(t *testing.T) {
 	type testCase struct {
 		in  []ProcessorFactory
@@ -75,21 +93,3 @@ func TestMakeProcessorFactoryMap(t *testing.T) {
 		assert.Equal(t, c.out, out)
 	}
 }
-
-func TestBaseProcessorFactory(t *testing.T) {
-	bpf := BaseProcessorFactory{}
-	assert.Panics(t, func() {
-		bpf.Type()
-	})
-	assert.Panics(t, func() {
-		bpf.CreateDefaultConfig()
-	})
-	assert.NotPanics(t, bpf.unexportedProcessor)
-	defaultCfg := config.NewProcessorSettings(config.NewComponentID("nop"))
-	_, err := bpf.CreateTracesProcessor(context.Background(), ProcessorCreateSettings{}, &defaultCfg, consumertest.NewNop())
-	assert.ErrorIs(t, err, componenterror.ErrDataTypeIsNotSupported)
-	_, err = bpf.CreateMetricsProcessor(context.Background(), ProcessorCreateSettings{}, &defaultCfg, consumertest.NewNop())
-	assert.ErrorIs(t, err, componenterror.ErrDataTypeIsNotSupported)
-	_, err = bpf.CreateLogsProcessor(context.Background(), ProcessorCreateSettings{}, &defaultCfg, consumertest.NewNop())
-	assert.ErrorIs(t, err, componenterror.ErrDataTypeIsNotSupported)
-}

internal/internalinterface/internalinterface.go

@@ -0,0 +1,30 @@
+// 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 internalinterface // import "go.opentelemetry.io/collector/internal/internalinterface"
+
+// InternalInterface is an interface used to prevent library consumers
+// to implement a given interface.
+type InternalInterface interface {
+	// unexportedMethod is a dummy method to force this interface to not be implemented.
+	unexportedMethod()
+}
+
+var _ InternalInterface = (*BaseInternal)(nil)
+
+// BaseInternal must be embedded on structs implementing InternalInterface.
+type BaseInternal struct{}
+
+// unexportedMethod implements the internal interface.
+func (*BaseInternal) unexportedMethod() {}

internal/internalinterface/internalinterface_test.go

@@ -0,0 +1,26 @@
+// 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 internalinterface // import "go.opentelemetry.io/collector/internal/internalinterface"
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBaseInternal(t *testing.T) {
+	base := BaseInternal{}
+	assert.NotPanics(t, base.unexportedMethod)
+}

processor/processorhelper/factory.go

@@ -18,8 +18,10 @@ import (
 	"context"
 
 	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/component/componenterror"
 	"go.opentelemetry.io/collector/config"
 	"go.opentelemetry.io/collector/consumer"
+	"go.opentelemetry.io/collector/internal/internalinterface"
 )
 
 // FactoryOption apply changes to ProcessorOptions.
@@ -38,7 +40,7 @@ type CreateMetricsProcessor func(context.Context, component.ProcessorCreateSetti
 type CreateLogsProcessor func(context.Context, component.ProcessorCreateSettings, config.Processor, consumer.Logs) (component.LogsProcessor, error)
 
 type factory struct {
-	component.BaseProcessorFactory
+	internalinterface.BaseInternal
 	cfgType                config.Type
 	createDefaultConfig    CreateDefaultConfig
 	createTracesProcessor  CreateTracesProcessor
@@ -100,7 +102,7 @@ func (f *factory) CreateTracesProcessor(
 	nextConsumer consumer.Traces,
 ) (component.TracesProcessor, error) {
 	if f.createTracesProcessor == nil {
-		return f.BaseProcessorFactory.CreateTracesProcessor(ctx, set, cfg, nextConsumer)
+		return nil, componenterror.ErrDataTypeIsNotSupported
 	}
 	return f.createTracesProcessor(ctx, set, cfg, nextConsumer)
 }
@@ -113,7 +115,7 @@ func (f *factory) CreateMetricsProcessor(
 	nextConsumer consumer.Metrics,
 ) (component.MetricsProcessor, error) {
 	if f.createMetricsProcessor == nil {
-		return f.BaseProcessorFactory.CreateMetricsProcessor(ctx, set, cfg, nextConsumer)
+		return nil, componenterror.ErrDataTypeIsNotSupported
 	}
 	return f.createMetricsProcessor(ctx, set, cfg, nextConsumer)
 }
@@ -126,7 +128,7 @@ func (f *factory) CreateLogsProcessor(
 	nextConsumer consumer.Logs,
 ) (component.LogsProcessor, error) {
 	if f.createLogsProcessor == nil {
-		return f.BaseProcessorFactory.CreateLogsProcessor(ctx, set, cfg, nextConsumer)
+		return nil, componenterror.ErrDataTypeIsNotSupported
 	}
 	return f.createLogsProcessor(ctx, set, cfg, nextConsumer)
 }