Add a new scraper package to replace scraperhelper

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>

scraper/Makefile

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+include ../Makefile.Common

scraper/README.md

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+# General Information
+
+A scraper defines how to connect and scrape telemetry data from an external source.
+
+<!-- status autogenerated section -->
+| Status        |           |
+| ------------- |-----------|
+| Stability     | [development]: metrics   |
+| Issues        | [![Open issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector?query=is%3Aissue%20is%3Aopen%20label%3Apkg%2F%20&label=open&color=orange&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector/issues?q=is%3Aopen+is%3Aissue+label%3Apkg%2F) [![Closed issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector?query=is%3Aissue%20is%3Aclosed%20label%3Apkg%2F%20&label=closed&color=blue&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector/issues?q=is%3Aclosed+is%3Aissue+label%3Apkg%2F) |
+
+[development]: https://github.com/open-telemetry/opentelemetry-collector/blob/main/docs/component-stability.md#development
+<!-- end autogenerated section -->

scraper/doc.go

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+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+//go:generate mdatagen metadata.yaml
+
+// Package scraper allows to define pull based receivers that can be configured using the scraperreceiver.
+package scraper // import "go.opentelemetry.io/collector/scraper"

scraper/factory.go

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+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package scraper // import "go.opentelemetry.io/collector/scraper"
+
+import (
+	"context"
+	"fmt"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/pipeline"
+)
+
+// Settings configures scraper creators.
+type Settings struct {
+	// ID returns the ID of the component that will be created.
+	ID component.ID
+
+	component.TelemetrySettings
+
+	// BuildInfo can be used by components for informational purposes.
+	BuildInfo component.BuildInfo
+}
+
+// Factory is factory interface for scrapers.
+//
+// This interface cannot be directly implemented. Implementations must
+// use the NewFactory to implement it.
+type Factory interface {
+	component.Factory
+
+	// CreateMetrics creates a Metrics scraper based on this config.
+	// If the scraper type does not support metrics,
+	// this function returns the error [pipeline.ErrSignalNotSupported].
+	// Implementers can assume `next` is never nil.
+	CreateMetrics(ctx context.Context, set Settings, cfg component.Config) (Metrics, error)
+
+	// MetricsStability gets the stability level of the Metrics scraper.
+	MetricsStability() component.StabilityLevel
+
+	unexportedFactoryFunc()
+}
+
+// FactoryOption apply changes to Options.
+type FactoryOption interface {
+	// applyOption applies the option.
+	applyOption(o *factory)
+}
+
+var _ FactoryOption = (*factoryOptionFunc)(nil)
+
+// factoryOptionFunc is a FactoryOption created through a function.
+type factoryOptionFunc func(*factory)
+
+func (f factoryOptionFunc) applyOption(o *factory) {
+	f(o)
+}
+
+type factory struct {
+	cfgType component.Type
+	component.CreateDefaultConfigFunc
+	CreateMetricsFunc
+	metricsStabilityLevel component.StabilityLevel
+}
+
+func (f *factory) Type() component.Type {
+	return f.cfgType
+}
+
+func (f *factory) unexportedFactoryFunc() {}
+
+func (f *factory) MetricsStability() component.StabilityLevel {
+	return f.metricsStabilityLevel
+}
+
+// CreateMetricsFunc is the equivalent of Factory.CreateMetrics().
+type CreateMetricsFunc func(context.Context, Settings, component.Config) (Metrics, error)
+
+// CreateMetrics implements Factory.CreateMetrics.
+func (f CreateMetricsFunc) CreateMetrics(ctx context.Context, set Settings, cfg component.Config) (Metrics, error) {
+	if f == nil {
+		return nil, pipeline.ErrSignalNotSupported
+	}
+	return f(ctx, set, cfg)
+}
+
+// WithMetrics overrides the default "error not supported" implementation for CreateMetrics and the default "undefined" stability level.
+func WithMetrics(createMetrics CreateMetricsFunc, sl component.StabilityLevel) FactoryOption {
+	return factoryOptionFunc(func(o *factory) {
+		o.metricsStabilityLevel = sl
+		o.CreateMetricsFunc = createMetrics
+	})
+}
+
+// NewFactory returns a Factory.
+func NewFactory(cfgType component.Type, createDefaultConfig component.CreateDefaultConfigFunc, options ...FactoryOption) Factory {
+	f := &factory{
+		cfgType:                 cfgType,
+		CreateDefaultConfigFunc: createDefaultConfig,
+	}
+	for _, opt := range options {
+		opt.applyOption(f)
+	}
+	return f
+}
+
+// MakeFactoryMap takes a list of receiver factories and returns a map with factory type as keys.
+// It returns a non-nil error when there are factories with duplicate type.
+func MakeFactoryMap(factories ...Factory) (map[component.Type]Factory, error) {
+	fMap := map[component.Type]Factory{}
+	for _, f := range factories {
+		if _, ok := fMap[f.Type()]; ok {
+			return fMap, fmt.Errorf("duplicate scraper factory %q", f.Type())
+		}
+		fMap[f.Type()] = f
+	}
+	return fMap, nil
+}

scraper/factory_test.go

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+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package scraper
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/component/componenttest"
+	"go.opentelemetry.io/collector/pipeline"
+)
+
+var testType = component.MustNewType("test")
+
+func nopSettings() Settings {
+	return Settings{
+		ID:                component.NewID(testType),
+		TelemetrySettings: componenttest.NewNopTelemetrySettings()}
+}
+
+func TestNewFactory(t *testing.T) {
+	defaultCfg := struct{}{}
+	f := NewFactory(
+		testType,
+		func() component.Config { return &defaultCfg })
+	assert.EqualValues(t, testType, f.Type())
+	assert.EqualValues(t, &defaultCfg, f.CreateDefaultConfig())
+	_, err := f.CreateMetrics(context.Background(), nopSettings(), &defaultCfg)
+	require.ErrorIs(t, err, pipeline.ErrSignalNotSupported)
+}
+
+func TestNewFactoryWithOptions(t *testing.T) {
+	var testType = component.MustNewType("test")
+	defaultCfg := struct{}{}
+	f := NewFactory(
+		testType,
+		func() component.Config { return &defaultCfg },
+		WithMetrics(createMetrics, component.StabilityLevelAlpha))
+	assert.EqualValues(t, testType, f.Type())
+	assert.EqualValues(t, &defaultCfg, f.CreateDefaultConfig())
+
+	assert.Equal(t, component.StabilityLevelAlpha, f.MetricsStability())
+	_, err := f.CreateMetrics(context.Background(), Settings{}, &defaultCfg)
+	require.NoError(t, err)
+}
+
+func TestMakeFactoryMap(t *testing.T) {
+	type testCase struct {
+		name string
+		in   []Factory
+		out  map[component.Type]Factory
+	}
+
+	p1 := NewFactory(component.MustNewType("p1"), nil)
+	p2 := NewFactory(component.MustNewType("p2"), nil)
+	testCases := []testCase{
+		{
+			name: "different names",
+			in:   []Factory{p1, p2},
+			out: map[component.Type]Factory{
+				p1.Type(): p1,
+				p2.Type(): p2,
+			},
+		},
+		{
+			name: "same name",
+			in:   []Factory{p1, p2, NewFactory(component.MustNewType("p1"), nil)},
+		},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.name, func(t *testing.T) {
+			out, err := MakeFactoryMap(tt.in...)
+			if tt.out == nil {
+				assert.Error(t, err)
+				return
+			}
+			require.NoError(t, err)
+			assert.Equal(t, tt.out, out)
+		})
+	}
+}
+
+func createMetrics(context.Context, Settings, component.Config) (Metrics, error) {
+	return NewMetrics(context.Background(), nopSettings(), newTestScrapeMetricsFunc(nil))
+}

scraper/go.mod

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+module go.opentelemetry.io/collector/scraper
+
+go 1.22.0
+
+require (
+	github.com/stretchr/testify v1.9.0
+	go.opentelemetry.io/collector/component v0.113.0
+	go.opentelemetry.io/collector/pdata v1.19.0
+	go.opentelemetry.io/collector/pipeline v0.113.0
+	go.uber.org/goleak v1.3.0
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/go-logr/logr v1.4.2 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/google/uuid v1.6.0 // indirect
+	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
+	github.com/modern-go/reflect2 v1.0.2 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	go.opentelemetry.io/collector/config/configtelemetry v0.113.0 // indirect
+	go.opentelemetry.io/otel v1.31.0 // indirect
+	go.opentelemetry.io/otel/metric v1.31.0 // indirect
+	go.opentelemetry.io/otel/sdk v1.31.0 // indirect
+	go.opentelemetry.io/otel/sdk/metric v1.31.0 // indirect
+	go.opentelemetry.io/otel/trace v1.31.0 // indirect
+	go.uber.org/multierr v1.11.0 // indirect
+	go.uber.org/zap v1.27.0 // indirect
+	golang.org/x/net v0.28.0 // indirect
+	golang.org/x/sys v0.26.0 // indirect
+	golang.org/x/text v0.17.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20240814211410-ddb44dafa142 // indirect
+	google.golang.org/grpc v1.67.1 // indirect
+	google.golang.org/protobuf v1.35.1 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)