Feature: task executor migration to go (#16549)

### Summary

Feature: Integrate parser

internal/parser/parser/factory.go

@@ -0,0 +1,86 @@
+//
+// Copyright 2026 The InfiniFlow Authors. All Rights Reserved.
+//
+// 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 parser
+
+import "fmt"
+
+// stubParser is a placeholder for parsers whose real implementation lives
+// in the DeepDoc inference service. The stub exists only to satisfy the
+// factory dispatch contract.
+type stubParser struct{ name string }
+
+func (p *stubParser) ParseWithResult(filename string, data []byte) ParseResult {
+	return ParseResult{Err: fmt.Errorf("%s: remote deepdoc dispatch not yet wired", p.name)}
+}
+
+// GetParserByID returns a parser for the given parser_id (matches Python FACTORY dispatch).
+// Most parser_ids handle PDF files with different strategies; the strategy is encoded
+// in the returned parser implementation. Stub implementations are replaced as
+// colleagues deliver real parsers.
+func GetParserByID(parserID string) (ParseResultProducer, error) {
+	switch parserID {
+	case "naive", "general":
+		return NewNaivePDFParser(), nil
+	case "paper":
+		return NewPaperPDFParser(), nil
+	case "book":
+		return NewBookPDFParser(), nil
+	case "presentation":
+		return NewPresentationParser(), nil
+	case "manual":
+		return NewManualPDFParser(), nil
+	case "laws":
+		return NewLawsPDFParser(), nil
+	case "qa":
+		return NewQAPDFParser(), nil
+	case "table":
+		return NewTableParser(), nil
+	case "resume":
+		return NewResumePDFParser(), nil
+	case "picture":
+		return NewPicturePDFParser(), nil
+	case "one":
+		return NewOnePDFParser(), nil
+	case "audio":
+		return NewAudioParser(), nil
+	case "email":
+		return NewEmailParser(), nil
+	case "tag":
+		return NewTagPDFParser(), nil
+	case "knowledge_graph":
+		return NewKGPDFParser(), nil
+	default:
+		return nil, fmt.Errorf("unknown parser_id: %s", parserID)
+	}
+}
+
+// Stub constructors for each parser type.
+func NewNaivePDFParser() *stubParser    { return &stubParser{name: "naive"} }
+func NewPaperPDFParser() *stubParser    { return &stubParser{name: "paper"} }
+func NewBookPDFParser() *stubParser     { return &stubParser{name: "book"} }
+func NewPresentationParser() *stubParser  { return &stubParser{name: "presentation"} }
+func NewManualPDFParser() *stubParser   { return &stubParser{name: "manual"} }
+func NewLawsPDFParser() *stubParser     { return &stubParser{name: "laws"} }
+func NewQAPDFParser() *stubParser       { return &stubParser{name: "qa"} }
+func NewTableParser() *stubParser       { return &stubParser{name: "table"} }
+func NewResumePDFParser() *stubParser   { return &stubParser{name: "resume"} }
+func NewPicturePDFParser() *stubParser  { return &stubParser{name: "picture"} }
+func NewOnePDFParser() *stubParser      { return &stubParser{name: "one"} }
+func NewAudioParser() *stubParser       { return &stubParser{name: "audio"} }
+func NewEmailParser() *stubParser       { return &stubParser{name: "email"} }
+func NewTagPDFParser() *stubParser      { return &stubParser{name: "tag"} }
+func NewKGPDFParser() *stubParser       { return &stubParser{name: "knowledge_graph"} }

internal/parser/parser/factory_test.go

@@ -0,0 +1,81 @@
+//
+//  Copyright 2026 The InfiniFlow Authors. All Rights Reserved.
+//
+//  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 parser
+
+import (
+	"testing"
+
+	"ragflow/internal/entity"
+)
+
+func TestGetParserByID_AllKnownIDs(t *testing.T) {
+	tests := []struct {
+		parserID string
+		wantNil  bool
+	}{
+		// PDF-based parsers
+		{string(entity.ParserTypeNaive), false},
+		{string(entity.ParserTypePaper), false},
+		{string(entity.ParserTypeBook), false},
+		{string(entity.ParserTypeManual), false},
+		{string(entity.ParserTypeLaws), false},
+		{string(entity.ParserTypeQA), false},
+		{string(entity.ParserTypeResume), false},
+		{string(entity.ParserTypePicture), false},
+		{string(entity.ParserTypeOne), false},
+		{string(entity.ParserTypeKG), false},
+		{string(entity.ParserTypeTag), false},
+		// Office parsers
+		{string(entity.ParserTypePresentation), false},
+		{string(entity.ParserTypeTable), false},
+		// Special parsers
+		{string(entity.ParserTypeAudio), false},
+		{string(entity.ParserTypeEmail), false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.parserID, func(t *testing.T) {
+			got, err := GetParserByID(tt.parserID)
+			if tt.wantNil {
+				if got != nil {
+					t.Errorf("GetParserByID(%q) = non-nil, want nil", tt.parserID)
+				}
+			} else {
+				if err != nil {
+					t.Errorf("GetParserByID(%q): %v", tt.parserID, err)
+				}
+				if got == nil {
+					t.Errorf("GetParserByID(%q) = nil, want non-nil", tt.parserID)
+				}
+			}
+		})
+	}
+}
+
+func TestGetParserByID_InvalidID(t *testing.T) {
+	_, err := GetParserByID("nonexistent")
+	if err == nil {
+		t.Fatal("expected error for invalid parser_id")
+	}
+}
+
+func TestGetParserByID_EmptyID(t *testing.T) {
+	_, err := GetParserByID("")
+	if err == nil {
+		t.Fatal("expected error for empty parser_id")
+	}
+}