feat: support symlink file detect (#5)

* feat: support symlink file detect
* fix: add point nil check
* fix: remove no use func
* fix: use setting error

Author: luohoufu

lib/reader/harvester/harvester.go

@@ -8,14 +8,14 @@ import (
 	"fmt"
 	"io"
 	"os"
-	"strings"
 
 	"infini.sh/agent/lib/reader"
 	"infini.sh/agent/lib/reader/linenumber"
 	"infini.sh/agent/lib/reader/multiline"
 	"infini.sh/agent/lib/reader/readfile"
 	"infini.sh/agent/lib/reader/readfile/encoding"
 	"infini.sh/agent/lib/reader/readjson"
+	"infini.sh/framework/core/errors"
 )
 
 type Harvester struct {
@@ -30,8 +30,8 @@ type Harvester struct {
 
 func NewHarvester(path string, offset int64) (*Harvester, error) {
 	f, err := readOpen(path)
-	if err != nil {
-		return nil, err
+	if f == nil || err != nil {
+		return nil, errors.Errorf("failed to open file(%s),%v", path, err)
 	}
 	_, err = f.Seek(offset, io.SeekStart)
 	if err != nil {
@@ -48,6 +48,9 @@ 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 +63,9 @@ 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 == nil || 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 +103,9 @@ func (h *Harvester) NewLogFileReader(pattern string, showLineNumber bool) (reade
 	var r reader.Reader
 	var err error
 
+	if h == nil || 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 +134,6 @@ 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

@@ -7,9 +7,10 @@ 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 +24,16 @@ 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 {