refactor(input/file): resolve file paths once

Signed-off-by: Dominik Rosiek <[email protected]>

operator/builtin/input/file/file.go

@@ -289,7 +289,7 @@ func (f *InputOperator) newReader(file *os.File, fp *Fingerprint, firstCheck boo
 		if err != nil {
 			return nil, err
 		}
-		newReader.Path = file.Name()
+		newReader.SetPath(file.Name())
 		return newReader, nil
 	}
 

operator/builtin/input/file/reader.go

@@ -26,19 +26,47 @@ import (
 	"golang.org/x/text/encoding"
 	"golang.org/x/text/transform"
 
-	"github.com/open-telemetry/opentelemetry-log-collection/entry"
 	"github.com/open-telemetry/opentelemetry-log-collection/errors"
 )
 
+// File attributes contains information about file paths
+type fileAttributes struct {
+	Name         string
+	Path         string
+	ResolvedName string
+	ResolvedPath string
+}
+
+// resolveFileAttributes resolves file attributes
+// and sets it to empty string in case of error
+func resolveFileAttributes(path string) *fileAttributes {
+	resolved, err := filepath.EvalSymlinks(path)
+	if err != nil {
+		resolved = ""
+	}
+
+	abs, err := filepath.Abs(resolved)
+	if err != nil {
+		abs = ""
+	}
+
+	return &fileAttributes{
+		Path:         path,
+		Name:         filepath.Base(path),
+		ResolvedPath: abs,
+		ResolvedName: filepath.Base(abs),
+	}
+}
+
 // Reader manages a single file
 type Reader struct {
 	Fingerprint *Fingerprint
 	Offset      int64
-	Path        string
 
-	generation int
-	fileInput  *InputOperator
-	file       *os.File
+	generation     int
+	fileInput      *InputOperator
+	file           *os.File
+	fileAttributes *fileAttributes
 
 	decoder      *encoding.Decoder
 	decodeBuffer []byte
@@ -49,20 +77,25 @@ type Reader struct {
 // NewReader creates a new file reader
 func (f *InputOperator) NewReader(path string, file *os.File, fp *Fingerprint) (*Reader, error) {
 	r := &Reader{
-		Fingerprint:   fp,
-		file:          file,
-		Path:          path,
-		fileInput:     f,
-		SugaredLogger: f.SugaredLogger.With("path", path),
-		decoder:       f.encoding.Encoding.NewDecoder(),
-		decodeBuffer:  make([]byte, 1<<12),
+		Fingerprint:    fp,
+		file:           file,
+		fileInput:      f,
+		SugaredLogger:  f.SugaredLogger.With("path", path),
+		decoder:        f.encoding.Encoding.NewDecoder(),
+		decodeBuffer:   make([]byte, 1<<12),
+		fileAttributes: resolveFileAttributes(path),
 	}
 	return r, nil
 }
 
+// SetPath sets fileAttributes based on new path
+func (r *Reader) SetPath(path string) {
+	r.fileAttributes = resolveFileAttributes(path)
+}
+
 // Copy creates a deep copy of a Reader
 func (f *Reader) Copy(file *os.File) (*Reader, error) {
-	reader, err := f.fileInput.NewReader(f.Path, file, f.Fingerprint.Copy())
+	reader, err := f.fileInput.NewReader(f.fileAttributes.Path, file, f.Fingerprint.Copy())
 	if err != nil {
 		return nil, err
 	}
@@ -145,40 +178,22 @@ func (f *Reader) emit(ctx context.Context, msgBuf []byte) error {
 		return fmt.Errorf("create entry: %s", err)
 	}
 
-	if err := e.Set(f.fileInput.FilePathField, f.Path); err != nil {
-		return err
-	}
-	if err := e.Set(f.fileInput.FileNameField, filepath.Base(f.Path)); err != nil {
-		return err
-	}
-	if err := f.resolvePath(e); err != nil {
-		return err
-	}
-
-	f.fileInput.Write(ctx, e)
-	return nil
-}
-
-// resolvePath resolves path to real and absolute form and add them into entry
-func (f *Reader) resolvePath(e *entry.Entry) error {
-	resolved, err := filepath.EvalSymlinks(f.Path)
-	if err != nil {
+	if err := e.Set(f.fileInput.FilePathField, f.fileAttributes.Path); err != nil {
 		return err
 	}
-
-	abs, err := filepath.Abs(resolved)
-	if err != nil {
+	if err := e.Set(f.fileInput.FileNameField, f.fileAttributes.Name); err != nil {
 		return err
 	}
 
-	if err := e.Set(f.fileInput.FilePathResolvedField, abs); err != nil {
+	if err := e.Set(f.fileInput.FilePathResolvedField, f.fileAttributes.ResolvedPath); err != nil {
 		return err
 	}
 
-	if err := e.Set(f.fileInput.FileNameResolvedField, filepath.Base(abs)); err != nil {
+	if err := e.Set(f.fileInput.FileNameResolvedField, f.fileAttributes.ResolvedName); err != nil {
 		return err
 	}
 
+	f.fileInput.Write(ctx, e)
 	return nil
 }