[chore][fileconsumer] Cleanup file handle when closed by reader (#26030)

Reboot of #25912

pkg/stanza/fileconsumer/file.go

@@ -157,10 +157,7 @@ func (m *Manager) consume(ctx context.Context, paths []string) {
 			r.ReadToEnd(ctx)
 			// Delete a file if deleteAfterRead is enabled and we reached the end of the file
 			if m.deleteAfterRead && r.eof {
-				r.Close()
-				if err := os.Remove(r.file.Name()); err != nil {
-					m.Errorf("could not delete %s", r.file.Name())
-				}
+				r.Delete()
 			}
 		}(r)
 	}

pkg/stanza/fileconsumer/file_test.go

@@ -4,6 +4,7 @@
 package fileconsumer
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 	"os"
@@ -1476,6 +1477,7 @@ func TestDeleteAfterRead_SkipPartials(t *testing.T) {
 	shortFileLine := tokenWithLength(bytesPerLine - 1)
 	longFileLines := 100000
 	longFileSize := longFileLines * bytesPerLine
+	longFileFirstLine := "first line of long file\n"
 
 	require.NoError(t, featuregate.GlobalRegistry().Set(allowFileDeletion.ID(), true))
 	defer func() {
@@ -1496,6 +1498,8 @@ func TestDeleteAfterRead_SkipPartials(t *testing.T) {
 	require.NoError(t, shortFile.Close())
 
 	longFile := openTemp(t, tempDir)
+	_, err = longFile.WriteString(longFileFirstLine)
+	require.NoError(t, err)
 	for line := 0; line < longFileLines; line++ {
 		_, err := longFile.WriteString(string(tokenWithLength(bytesPerLine-1)) + "\n")
 		require.NoError(t, err)
@@ -1538,8 +1542,7 @@ func TestDeleteAfterRead_SkipPartials(t *testing.T) {
 	// Verify that only long file is remembered and that (0 < offset < fileSize)
 	require.Equal(t, 1, len(operator.knownFiles))
 	reader := operator.knownFiles[0]
-	require.Equal(t, longFile.Name(), reader.file.Name())
-	require.Greater(t, reader.Offset, int64(0))
+	require.True(t, bytes.HasPrefix(reader.Fingerprint.FirstBytes, []byte(longFileFirstLine)))
 	require.Less(t, reader.Offset, int64(longFileSize))
 }
 

pkg/stanza/fileconsumer/reader.go

@@ -124,12 +124,25 @@ func (r *reader) finalizeHeader() {
 	r.HeaderFinalized = true
 }
 
+// Delete will close and delete the file
+func (r *reader) Delete() {
+	if r.file == nil {
+		return
+	}
+	f := r.file
+	r.Close()
+	if err := os.Remove(f.Name()); err != nil {
+		r.Errorf("could not delete %s", f.Name())
+	}
+}
+
 // Close will close the file
 func (r *reader) Close() {
 	if r.file != nil {
 		if err := r.file.Close(); err != nil {
 			r.Debugw("Problem closing reader", zap.Error(err))
 		}
+		r.file = nil
 	}
 
 	if r.headerReader != nil {