Remove *os.File hack

Use file.AtomicOpener directly when writing the keepalived config file.
This was the only hack that relied on using *os.File directly.

Signed-off-by: Tom Wieczorek <twieczorek@mirantis.com>

internal/pkg/file/atomic.go

@@ -323,10 +323,7 @@ func remove(fd *os.File) error {
 // https://github.com/golang/go/issues/22397#issuecomment-498856679
 func WriteAtomically(fileName string, perm os.FileMode, write func(file io.Writer) error) (err error) {
 	return AtomicWithTarget(fileName).WithPermissions(perm).Do(func(unbuffered AtomicWriter) error {
-		// Pass the real file to the callback, so that callers that are cheating
-		// and relied on this implementation detail won't break.
-		fd := unbuffered.(*Atomic).fd
-		return write(fd)
+		return write(unbuffered)
 	})
 }
 

internal/pkg/file/atomic_test.go

@@ -134,9 +134,9 @@ func TestWriteAtomically(t *testing.T) {
 		file := filepath.Join(dir, "file")
 
 		errs := flatten(WriteAtomically(file, 0644, func(file io.Writer) error {
-			c, ok := file.(io.Closer)
-			require.True(t, ok, "Not closeable: %T", file)
-			require.NoError(t, c.Close())
+			a, ok := file.(*Atomic)
+			require.True(t, ok, "Not an Atomic: %T", file)
+			require.NoError(t, a.fd.Close())
 			return nil
 		}))
 
@@ -169,9 +169,9 @@ func TestWriteAtomically(t *testing.T) {
 
 		var tempPath string
 		err := WriteAtomically(file, 0644, func(file io.Writer) error {
-			n, ok := file.(interface{ Name() string })
-			require.True(t, ok, "Doesn't have a name: %T", file)
-			tempPath = n.Name()
+			a, ok := file.(*Atomic)
+			require.True(t, ok, "Not an Atomic: %T", file)
+			tempPath = a.fd.Name()
 			require.Equal(t, dir, filepath.Dir(tempPath))
 			if runtime.GOOS == "windows" {
 				t.Skip("Cannot remove a file which is still opened on Windows")
@@ -245,9 +245,9 @@ func TestWriteAtomically(t *testing.T) {
 
 		var tempPath string
 		errs := flatten(WriteAtomically(file, 0755, func(file io.Writer) error {
-			n, ok := file.(interface{ Name() string })
-			require.True(t, ok, "Doesn't have a name: %T", file)
-			tempPath = n.Name()
+			a, ok := file.(*Atomic)
+			require.True(t, ok, "Not an Atomic: %T", file)
+			tempPath = a.fd.Name()
 			require.Equal(t, dir, filepath.Dir(tempPath))
 
 			if runtime.GOOS == "windows" {

pkg/component/controller/cplb_unix.go

@@ -23,9 +23,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"io"
 	"net"
-	"os"
 	"path/filepath"
 	"slices"
 	"text/template"
@@ -273,17 +271,16 @@ func (k *Keepalived) generateKeepalivedTemplate() error {
 		VRRPInstances: k.Config.VRRPInstances,
 	}
 
-	if err := file.WriteAtomically(k.configFilePath, 0400, func(file io.Writer) error {
-		if err := file.(*os.File).Chown(k.uid, -1); err != nil {
-			return err
-		}
-
-		w := bufio.NewWriter(file)
-		if err := template.Execute(w, kc); err != nil {
-			return err
-		}
-		return w.Flush()
-	}); err != nil {
+	if err := file.AtomicWithTarget(k.configFilePath).
+		WithPermissions(0400).
+		WithOwner(k.uid).
+		Do(func(unbuffered file.AtomicWriter) error {
+			w := bufio.NewWriter(unbuffered)
+			if err := template.Execute(w, kc); err != nil {
+				return err
+			}
+			return w.Flush()
+		}); err != nil {
 		return fmt.Errorf("failed to write keepalived config file: %w", err)
 	}