[exporter] moved mergeBatchFunc and mergeBatchSplitFunc to request (open-telemetry#11459)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description

This PR changes `mergeBatchFunc` and `mergeBatchSplit` function as a
member function of `batchRequest`.

<!-- Issue number if applicable -->
#### Link to tracking issue

<!--Describe what testing was performed and which tests were added.-->
#### Testing

<!--Describe the documentation added.-->
#### Documentation

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Author: sfc-gh-sili

.chloggen/merge-function-as-requet-method.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: breaking
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: exporter
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Made mergeFunc and mergeSplitFunc required method of exporter.Request
+
+# One or more tracking issues or pull requests related to the change
+issues: [10368]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+  mergeFunc and mergeSplitFunc used to be part of the configuration pass to the exporter. Now it is changed
+  | to be a method function of request.
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [api]

exporter/exporterbatcher/batch_func.go

@@ -69,11 +69,3 @@ func WithCapabilities(capabilities consumer.Capabilities) Option {
 func WithBatcher(cfg exporterbatcher.Config) Option {
 	return internal.WithBatcher(cfg)
 }
-
-// WithBatchFuncs enables setting custom batch merge functions.
-// This API is at the early stage of development and may change without backward compatibility
-// until https://github.com/open-telemetry/opentelemetry-collector/issues/8122 is resolved.
-func WithBatchFuncs(mf exporterbatcher.BatchMergeFunc[Request],
-	msf exporterbatcher.BatchMergeSplitFunc[Request]) Option {
-	return internal.WithBatchFuncs(mf, msf)
-}

exporter/exporterhelper/common.go

@@ -14,7 +14,6 @@ require (
 	go.opentelemetry.io/collector/exporter v0.111.0
 	go.opentelemetry.io/collector/exporter/exporterprofiles v0.111.0
 	go.opentelemetry.io/collector/exporter/exportertest v0.111.0
-	go.opentelemetry.io/collector/pdata v1.17.0
 	go.opentelemetry.io/collector/pdata/pprofile v0.111.0
 	go.opentelemetry.io/collector/pdata/testdata v0.111.0
 	go.opentelemetry.io/collector/pipeline/pipelineprofiles v0.0.0-20241021162523-3193106bf4b1
@@ -38,6 +37,7 @@ require (
 	go.opentelemetry.io/collector/config/configtelemetry v0.111.0 // indirect
 	go.opentelemetry.io/collector/extension v0.111.0 // indirect
 	go.opentelemetry.io/collector/extension/experimental/storage v0.111.0 // indirect
+	go.opentelemetry.io/collector/pdata v1.17.0 // indirect
 	go.opentelemetry.io/collector/pipeline v0.111.0 // indirect
 	go.opentelemetry.io/collector/receiver v0.111.0 // indirect
 	go.opentelemetry.io/collector/receiver/receiverprofiles v0.111.0 // indirect

exporter/exporterhelper/exporterhelperprofiles/go.mod

@@ -88,7 +88,6 @@ func NewProfilesExporter(
 	}
 	profilesOpts := []exporterhelper.Option{
 		internal.WithMarshaler(profilesRequestMarshaler), internal.WithUnmarshaler(newProfileRequestUnmarshalerFunc(pusher)),
-		internal.WithBatchFuncs(mergeProfiles, mergeSplitProfiles),
 	}
 	return NewProfilesRequestExporter(ctx, set, requestFromProfiles(pusher), append(profilesOpts, options...)...)
 }

exporter/exporterhelper/exporterhelperprofiles/profiles.go

@@ -12,29 +12,28 @@ import (
 	"go.opentelemetry.io/collector/pdata/pprofile"
 )
 
-// mergeProfiles merges two profiles requests into one.
-func mergeProfiles(_ context.Context, r1 exporterhelper.Request, r2 exporterhelper.Request) (exporterhelper.Request, error) {
-	tr1, ok1 := r1.(*profilesRequest)
+// Merge merges two profiles requests into one.
+func (req *profilesRequest) Merge(_ context.Context, r2 exporterhelper.Request) (exporterhelper.Request, error) {
 	tr2, ok2 := r2.(*profilesRequest)
-	if !ok1 || !ok2 {
+	if !ok2 {
 		return nil, errors.New("invalid input type")
 	}
-	tr2.pd.ResourceProfiles().MoveAndAppendTo(tr1.pd.ResourceProfiles())
-	return tr1, nil
+	tr2.pd.ResourceProfiles().MoveAndAppendTo(req.pd.ResourceProfiles())
+	return req, nil
 }
 
-// mergeSplitProfiles splits and/or merges the profiles into multiple requests based on the MaxSizeConfig.
-func mergeSplitProfiles(_ context.Context, cfg exporterbatcher.MaxSizeConfig, r1 exporterhelper.Request, r2 exporterhelper.Request) ([]exporterhelper.Request, error) {
+// MergeSplit splits and/or merges the profiles into multiple requests based on the MaxSizeConfig.
+func (req *profilesRequest) MergeSplit(_ context.Context, cfg exporterbatcher.MaxSizeConfig, r2 exporterhelper.Request) ([]exporterhelper.Request, error) {
 	var (
 		res          []exporterhelper.Request
 		destReq      *profilesRequest
 		capacityLeft = cfg.MaxSizeItems
 	)
-	for _, req := range []exporterhelper.Request{r1, r2} {
-		if req == nil {
+	for _, r := range []exporterhelper.Request{req, r2} {
+		if r == nil {
 			continue
 		}
-		srcReq, ok := req.(*profilesRequest)
+		srcReq, ok := r.(*profilesRequest)
 		if !ok {
 			return nil, errors.New("invalid input type")
 		}

exporter/exporterhelper/exporterhelperprofiles/profiles_batch.go

@@ -12,27 +12,25 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
-	"go.opentelemetry.io/collector/consumer"
 	"go.opentelemetry.io/collector/exporter/exporterbatcher"
 	"go.opentelemetry.io/collector/exporter/exporterhelper"
 	"go.opentelemetry.io/collector/pdata/pprofile"
-	"go.opentelemetry.io/collector/pdata/ptrace"
 	"go.opentelemetry.io/collector/pdata/testdata"
 )
 
 func TestMergeProfiles(t *testing.T) {
 	pr1 := &profilesRequest{pd: testdata.GenerateProfiles(2)}
 	pr2 := &profilesRequest{pd: testdata.GenerateProfiles(3)}
-	res, err := mergeProfiles(context.Background(), pr1, pr2)
+	res, err := pr1.Merge(context.Background(), pr2)
 	require.NoError(t, err)
 	fmt.Fprintf(os.Stdout, "%#v\n", res.(*profilesRequest).pd)
 	assert.Equal(t, 5, res.(*profilesRequest).pd.SampleCount())
 }
 
 func TestMergeProfilesInvalidInput(t *testing.T) {
-	pr1 := &tracesRequest{td: testdata.GenerateTraces(2)}
+	pr1 := &dummyRequest{}
 	pr2 := &profilesRequest{pd: testdata.GenerateProfiles(3)}
-	_, err := mergeProfiles(context.Background(), pr1, pr2)
+	_, err := pr2.Merge(context.Background(), pr1)
 	assert.Error(t, err)
 }
 
@@ -51,13 +49,6 @@ func TestMergeSplitProfiles(t *testing.T) {
 			pr2:      &profilesRequest{pd: pprofile.NewProfiles()},
 			expected: []*profilesRequest{{pd: pprofile.NewProfiles()}},
 		},
-		{
-			name:     "both_requests_nil",
-			cfg:      exporterbatcher.MaxSizeConfig{MaxSizeItems: 10},
-			pr1:      nil,
-			pr2:      nil,
-			expected: []*profilesRequest{},
-		},
 		{
 			name:     "first_request_empty",
 			cfg:      exporterbatcher.MaxSizeConfig{MaxSizeItems: 10},
@@ -66,17 +57,10 @@ func TestMergeSplitProfiles(t *testing.T) {
 			expected: []*profilesRequest{{pd: testdata.GenerateProfiles(5)}},
 		},
 		{
-			name:     "first_requests_nil",
-			cfg:      exporterbatcher.MaxSizeConfig{MaxSizeItems: 10},
-			pr1:      nil,
-			pr2:      &profilesRequest{pd: testdata.GenerateProfiles(5)},
-			expected: []*profilesRequest{{pd: testdata.GenerateProfiles(5)}},
-		},
-		{
-			name:     "first_nil_second_empty",
+			name:     "first_empty_second_nil",
 			cfg:      exporterbatcher.MaxSizeConfig{MaxSizeItems: 10},
-			pr1:      nil,
-			pr2:      &profilesRequest{pd: pprofile.NewProfiles()},
+			pr1:      &profilesRequest{pd: pprofile.NewProfiles()},
+			pr2:      nil,
 			expected: []*profilesRequest{{pd: pprofile.NewProfiles()}},
 		},
 		{
@@ -93,8 +77,8 @@ func TestMergeSplitProfiles(t *testing.T) {
 		{
 			name: "split_only",
 			cfg:  exporterbatcher.MaxSizeConfig{MaxSizeItems: 4},
-			pr1:  nil,
-			pr2:  &profilesRequest{pd: testdata.GenerateProfiles(10)},
+			pr1:  &profilesRequest{pd: testdata.GenerateProfiles(10)},
+			pr2:  nil,
 			expected: []*profilesRequest{
 				{pd: testdata.GenerateProfiles(4)},
 				{pd: testdata.GenerateProfiles(4)},
@@ -133,7 +117,7 @@ func TestMergeSplitProfiles(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			res, err := mergeSplitProfiles(context.Background(), tt.cfg, tt.pr1, tt.pr2)
+			res, err := tt.pr1.MergeSplit(context.Background(), tt.cfg, tt.pr2)
 			require.NoError(t, err)
 			assert.Equal(t, len(tt.expected), len(res))
 			for i, r := range res {
@@ -145,9 +129,9 @@ func TestMergeSplitProfiles(t *testing.T) {
 }
 
 func TestMergeSplitProfilesInvalidInput(t *testing.T) {
-	r1 := &tracesRequest{td: testdata.GenerateTraces(2)}
+	r1 := &dummyRequest{}
 	r2 := &profilesRequest{pd: testdata.GenerateProfiles(3)}
-	_, err := mergeSplitProfiles(context.Background(), exporterbatcher.MaxSizeConfig{}, r1, r2)
+	_, err := r2.MergeSplit(context.Background(), exporterbatcher.MaxSizeConfig{}, r1)
 	assert.Error(t, err)
 }
 
@@ -160,15 +144,23 @@ func TestExtractProfiles(t *testing.T) {
 	}
 }
 
-type tracesRequest struct {
-	td     ptrace.Traces
-	pusher consumer.ConsumeTracesFunc
+// dummyRequest implements Request. It is for checking that merging two request types would fail
+type dummyRequest struct {
+}
+
+func (req *dummyRequest) Export(_ context.Context) error {
+	return nil
+}
+
+func (req *dummyRequest) ItemsCount() int {
+	return 1
 }
 
-func (req *tracesRequest) Export(ctx context.Context) error {
-	return req.pusher(ctx, req.td)
+func (req *dummyRequest) Merge(_ context.Context, _ exporterhelper.Request) (exporterhelper.Request, error) {
+	return nil, nil
 }
 
-func (req *tracesRequest) ItemsCount() int {
-	return req.td.SpanCount()
+func (req *dummyRequest) MergeSplit(_ context.Context, _ exporterbatcher.MaxSizeConfig, _ exporterhelper.Request) (
+	[]exporterhelper.Request, error) {
+	return nil, nil
 }

exporter/exporterhelper/exporterhelperprofiles/profiles_batch_test.go

@@ -35,9 +35,6 @@ type BaseExporter struct {
 
 	Signal pipeline.Signal
 
-	BatchMergeFunc      exporterbatcher.BatchMergeFunc[internal.Request]
-	BatchMergeSplitfunc exporterbatcher.BatchMergeSplitFunc[internal.Request]
-
 	Marshaler   exporterqueue.Marshaler[internal.Request]
 	Unmarshaler exporterqueue.Unmarshaler[internal.Request]
 
@@ -104,10 +101,7 @@ func NewBaseExporter(set exporter.Settings, signal pipeline.Signal, osf ObsrepSe
 	}
 
 	if be.BatcherCfg.Enabled {
-		bs := NewBatchSender(be.BatcherCfg, be.Set, be.BatchMergeFunc, be.BatchMergeSplitfunc)
-		if bs.mergeFunc == nil || bs.mergeSplitFunc == nil {
-			err = multierr.Append(err, fmt.Errorf("WithRequestBatchFuncs must be provided for the batcher applied to the request-based exporters"))
-		}
+		bs := NewBatchSender(be.BatcherCfg, be.Set)
 		be.BatchSender = bs
 	}
 
@@ -298,16 +292,6 @@ func WithUnmarshaler(unmarshaler exporterqueue.Unmarshaler[internal.Request]) Op
 	}
 }
 
-// withBatchFuncs is used to set the functions for merging and splitting batches for OLTP-based exporters.
-// It must be provided as the first option when creating a new exporter helper.
-func WithBatchFuncs(mf exporterbatcher.BatchMergeFunc[internal.Request], msf exporterbatcher.BatchMergeSplitFunc[internal.Request]) Option {
-	return func(o *BaseExporter) error {
-		o.BatchMergeFunc = mf
-		o.BatchMergeSplitfunc = msf
-		return nil
-	}
-}
-
 func CheckStatus(t *testing.T, sd sdktrace.ReadOnlySpan, err error) {
 	if err != nil {
 		require.Equal(t, codes.Error, sd.Status().Code, "SpanData %v", sd)

exporter/exporterhelper/internal/base_exporter.go

@@ -24,9 +24,7 @@ import (
 // - concurrencyLimit is reached.
 type BatchSender struct {
 	BaseRequestSender
-	cfg            exporterbatcher.Config
-	mergeFunc      exporterbatcher.BatchMergeFunc[internal.Request]
-	mergeSplitFunc exporterbatcher.BatchMergeSplitFunc[internal.Request]
+	cfg exporterbatcher.Config
 
 	// concurrencyLimit is the maximum number of goroutines that can be blocked by the batcher.
 	// If this number is reached and all the goroutines are busy, the batch will be sent right away.
@@ -46,14 +44,11 @@ type BatchSender struct {
 }
 
 // newBatchSender returns a new batch consumer component.
-func NewBatchSender(cfg exporterbatcher.Config, set exporter.Settings,
-	mf exporterbatcher.BatchMergeFunc[internal.Request], msf exporterbatcher.BatchMergeSplitFunc[internal.Request]) *BatchSender {
+func NewBatchSender(cfg exporterbatcher.Config, set exporter.Settings) *BatchSender {
 	bs := &BatchSender{
 		activeBatch:        newEmptyBatch(),
 		cfg:                cfg,
 		logger:             set.Logger,
-		mergeFunc:          mf,
-		mergeSplitFunc:     msf,
 		shutdownCh:         nil,
 		shutdownCompleteCh: make(chan struct{}),
 		stopped:            &atomic.Bool{},
@@ -156,10 +151,17 @@ func (bs *BatchSender) Send(ctx context.Context, req internal.Request) error {
 func (bs *BatchSender) sendMergeSplitBatch(ctx context.Context, req internal.Request) error {
 	bs.mu.Lock()
 
-	reqs, err := bs.mergeSplitFunc(ctx, bs.cfg.MaxSizeConfig, bs.activeBatch.request, req)
-	if err != nil || len(reqs) == 0 {
+	var reqs []internal.Request
+	var mergeSplitErr error
+	if bs.activeBatch.request == nil {
+		reqs, mergeSplitErr = req.MergeSplit(ctx, bs.cfg.MaxSizeConfig, nil)
+	} else {
+		reqs, mergeSplitErr = bs.activeBatch.request.MergeSplit(ctx, bs.cfg.MaxSizeConfig, req)
+	}
+
+	if mergeSplitErr != nil || len(reqs) == 0 {
 		bs.mu.Unlock()
-		return err
+		return mergeSplitErr
 	}
 
 	bs.activeRequests.Add(1)
@@ -201,7 +203,7 @@ func (bs *BatchSender) sendMergeBatch(ctx context.Context, req internal.Request)
 
 	if bs.activeBatch.request != nil {
 		var err error
-		req, err = bs.mergeFunc(ctx, bs.activeBatch.request, req)
+		req, err = bs.activeBatch.request.Merge(ctx, req)
 		if err != nil {
 			bs.mu.Unlock()
 			return err