fix(file): scanner dynamic buffer (#2959)

Signed-off-by: Jiyong Huang <huangjy@emqx.io>

internal/io/file/reader/csv.go

@@ -60,7 +60,7 @@ func (r *CsvReader) Provision(ctx api.StreamContext, props map[string]any) error
 	return nil
 }
 
-func (r *CsvReader) Bind(ctx api.StreamContext, fileStream io.Reader) error {
+func (r *CsvReader) Bind(ctx api.StreamContext, fileStream io.Reader, _ int) error {
 	cr := csv.NewReader(fileStream)
 	cr.Comma = rune(r.config.Delimiter[0])
 	cr.TrimLeadingSpace = true

internal/io/file/reader/lines.go

@@ -1,3 +1,17 @@
+// Copyright 2024 EMQ Technologies Co., Ltd.
+//
+// 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 reader
 
 import (
@@ -22,8 +36,14 @@ func (r *LinesReader) Provision(ctx api.StreamContext, props map[string]any) err
 	return nil
 }
 
-func (r *LinesReader) Bind(ctx api.StreamContext, fileStream io.Reader) error {
+func (r *LinesReader) Bind(ctx api.StreamContext, fileStream io.Reader, maxSize int) error {
+	if maxSize <= 0 {
+		ctx.GetLogger().Errorf("maxSize must be > 0, defaul to 1MB")
+		// default to 1MB
+		maxSize = 1 << 20
+	}
 	scanner := bufio.NewScanner(fileStream)
+	scanner.Buffer(nil, maxSize)
 	scanner.Split(bufio.ScanLines)
 	r.scanner = scanner
 	return nil
@@ -34,7 +54,10 @@ func (r *LinesReader) Read(ctx api.StreamContext) (any, error) {
 	if !succ {
 		return nil, io.EOF
 	}
-	return r.scanner.Bytes(), nil
+	b := r.scanner.Bytes()
+	d := make([]byte, len(b))
+	copy(d, b)
+	return d, nil
 }
 
 func (r *LinesReader) IsBytesReader() bool {

internal/io/file/source.go

@@ -214,11 +214,20 @@ func (fs *Source) parseFile(ctx api.StreamContext, file string, ingest api.Tuple
 		err error
 		r   io.Reader
 	)
-	r, err = os.Open(file)
+	f, err := os.Open(file)
 	if err != nil {
 		ctx.GetLogger().Debugf("prepare file %s error: %v", file, err)
 		ingestError(ctx, err)
 	}
+	r = f
+	// This is the buffer size, 1MB by default
+	maxSize := 1 << 20
+	info, err := f.Stat()
+	if err != nil {
+		ctx.GetLogger().Debugf("get file info for %s error: %v", file, err)
+	} else {
+		maxSize = int(info.Size())
+	}
 	if fs.config.IgnoreStartLines > 0 || fs.config.IgnoreEndLines > 0 {
 		r = ignoreLines(ctx, r, fs.config.IgnoreStartLines, fs.config.IgnoreEndLines)
 	}
@@ -231,14 +240,17 @@ func (fs *Source) parseFile(ctx api.StreamContext, file string, ingest api.Tuple
 	meta := map[string]any{"file": file}
 	// Read line or read all
 	if fs.reader != nil {
-		err = fs.reader.Bind(ctx, r)
+		err = fs.reader.Bind(ctx, r, maxSize)
 		if err != nil {
 			ingestError(ctx, err)
 			return
 		}
 		for {
 			line, err := fs.reader.Read(ctx)
 			if err != nil {
+				if err != io.EOF {
+					ctx.GetLogger().Errorf("read file %s error: %v", file, err)
+				}
 				break
 			}
 			rcvTime := timex.GetNow()

internal/io/file/source_test.go

@@ -184,7 +184,7 @@ func TestSourceProvision(t *testing.T) {
 			},
 		},
 		{
-			name: "no decompression for stream typs",
+			name: "no decompression for stream types",
 			props: map[string]any{
 				"datasource":    name,
 				"path":          path,

pkg/modules/file.go

@@ -47,7 +47,7 @@ type FileStreamReader interface {
 	// Provision Set up the static properties
 	Provision(ctx api.StreamContext, props map[string]any) error
 	// Bind set the file stream. Make sure the previous read has done
-	Bind(ctx api.StreamContext, fileStream io.Reader) error
+	Bind(ctx api.StreamContext, fileStream io.Reader, maxSize int) error
 	// Read the next record. Returns EOF when the input has reached its end.
 	Read(ctx api.StreamContext) (any, error)
 	// IsBytesReader If is bytes reader, Read must return []byte, otherwise return map or []map