feat: support symlink file detect

Author: luohoufu

lib/reader/harvester/harvester.go

@@ -8,7 +8,6 @@ import (
 	"fmt"
 	"io"
 	"os"
-	"strings"
 
 	"infini.sh/agent/lib/reader"
 	"infini.sh/agent/lib/reader/linenumber"
@@ -30,7 +29,7 @@ type Harvester struct {
 
 func NewHarvester(path string, offset int64) (*Harvester, error) {
 	f, err := readOpen(path)
-	if err != nil {
+	if f == nil || err != nil {
 		return nil, err
 	}
 	_, err = f.Seek(offset, io.SeekStart)
@@ -48,6 +47,9 @@ func NewHarvester(path string, offset int64) (*Harvester, error) {
 	}
 	h.encodingFactory = encodingFactory
 	h.encoding, err = h.encodingFactory(f)
+	if err != nil {
+		return nil, err
+	}
 	return h, nil
 }
 
@@ -60,6 +62,9 @@ func readOpen(path string) (*os.File, error) {
 func (h *Harvester) NewJsonFileReader(pattern string, showLineNumber bool) (reader.Reader, error) {
 	var r reader.Reader
 	var err error
+	if h.file == nil {
+		return nil, fmt.Errorf("file is nil")
+	}
 
 	encReaderMaxBytes := h.config.MaxBytes * 4
 	r, err = readfile.NewEncodeReader(h.file, readfile.Config{
@@ -97,6 +102,9 @@ func (h *Harvester) NewLogFileReader(pattern string, showLineNumber bool) (reade
 	var r reader.Reader
 	var err error
 
+	if h.file == nil {
+		return nil, fmt.Errorf("file is nil")
+	}
 	encReaderMaxBytes := h.config.MaxBytes * 4
 	r, err = readfile.NewEncodeReader(h.file, readfile.Config{
 		Codec:      h.encoding,
@@ -125,16 +133,6 @@ func (h *Harvester) NewLogFileReader(pattern string, showLineNumber bool) (reade
 	return h.reader, nil
 }
 
-// NewPlainTextRead
-// 返回一行内容，即使一条日志包含多行(如错误堆栈)，也只返回一行。
-func (h *Harvester) NewPlainTextRead(showLineNumber bool) (reader.Reader, error) {
-	if strings.HasSuffix(h.file.Name(), ".json") {
-		return h.NewJsonFileReader("", showLineNumber)
-	} else {
-		return h.NewLogFileReader("", showLineNumber)
-	}
-}
-
 func (h *Harvester) Close() error {
 	err := h.reader.Close()
 	if err != nil {

lib/util/file.go

@@ -1,3 +1,38 @@
+// CountFileRows counts the number of rows in the specified file.
+// It takes a file path as an argument and returns the row count and an error if any.
+// If the file cannot be opened, it returns an error.
+//
+// Parameters:
+//   - filePath: The path to the file to be read.
+//
+// Returns:
+//   - int64: The number of rows in the file.
+//   - error: An error if the file cannot be opened or read.
+//
+// Example usage:
+//   count, err := CountFileRows("/path/to/file")
+//   if err != nil {
+//       log.Fatal(err)
+//   }
+//   fmt.Println("Number of rows:", count)
+
+// ResolveSymlink resolves the target file path of a symbolic link.
+// It takes a symbolic link path as an argument and returns the absolute path of the target file and an error if any.
+// If the symbolic link cannot be resolved, it returns an error.
+//
+// Parameters:
+//   - link: The path to the symbolic link.
+//
+// Returns:
+//   - string: The absolute path of the target file.
+//   - error: An error if the symbolic link cannot be resolved.
+//
+// Example usage:
+//   realPath, err := ResolveSymlink("/path/to/symlink")
+//   if err != nil {
+//       log.Fatal(err)
+//   }
+//   fmt.Println("Resolved path:", realPath)
 /* Copyright © INFINI Ltd. All rights reserved.
  * Web: https://infinilabs.com
  * Email: hello#infini.ltd */
@@ -7,9 +42,10 @@ package util
 import (
 	"bufio"
 	"os"
+	"path/filepath"
 )
 
-func CountFileRows(filePath string) (int64, error){
+func CountFileRows(filePath string) (int64, error) {
 	file, err := os.Open(filePath)
 	if err != nil {
 		return 0, err
@@ -23,3 +59,16 @@ func CountFileRows(filePath string) (int64, error){
 	}
 	return count, nil
 }
+
+// ResolveSymlink Parse the target file path of the soft link
+func ResolveSymlink(link string) (string, error) {
+	realPath, err := filepath.EvalSymlinks(link)
+	if err != nil {
+		return "", err
+	}
+	absPath, err := filepath.Abs(realPath)
+	if err != nil {
+		return "", err
+	}
+	return absPath, nil
+}

plugin/logs/file_detect.go

@@ -10,6 +10,7 @@ import (
 	"path/filepath"
 
 	log "github.com/cihub/seelog"
+	"infini.sh/agent/lib/util"
 )
 
 type Operation uint8
@@ -79,6 +80,19 @@ func (w *FileDetector) Detect(ctx context.Context) {
 }
 
 func (w *FileDetector) judgeEvent(ctx context.Context, path string, info os.FileInfo, pattern *Pattern) {
+	if info.Mode()&os.ModeSymlink != 0 {
+		realPath, err := util.ResolveSymlink(path)
+		if err != nil {
+			log.Error(err)
+			return
+		}
+		info, err = os.Lstat(realPath)
+		if err != nil {
+			log.Error(err)
+			return
+		}
+		path = realPath
+	}
 	preState, err := GetFileState(path)
 	isSameFile := w.IsSameFile(preState, info, path)
 	if err != nil || preState == (FileState{}) || !isSameFile {