GoogleContainerTools/skaffold · error

opening %s: %w

Error message

opening %s: %w

What it means

In the v2 event package, after directory creation succeeds, SaveEventsToFile opens the file with O_APPEND|O_WRONLY|O_CREATE (mode 0600). Failures are wrapped as 'opening %s'. The directory exists at this point, so the problem is with the file itself.

Source

Thrown at pkg/skaffold/event/v2/event.go:322

			}
			ev.state.DebuggingContainers = ev.state.DebuggingContainers[:n]
		}
		ev.stateLock.Unlock()
	}
	ev.logEvent(event)
}

// SaveEventsToFile saves the current event log to the filepath provided
func SaveEventsToFile(fp string) error {
	handler.logLock.Lock()
	// Ensure that the filepath provided has the directories available when attemping to save the file.
	dir := filepath.Dir(fp)
	if err := os.MkdirAll(dir, 0700); err != nil {
		return fmt.Errorf("unable to create directory %q: %w", dir, err)
	}
	f, err := os.OpenFile(fp, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0600)
	if err != nil {
		return fmt.Errorf("opening %s: %w", fp, err)
	}
	defer f.Close()
	marshaller := jsonpb.Marshaler{}
	for _, ev := range handler.eventLog {
		contents := bytes.NewBuffer([]byte{})
		if err := marshaller.Marshal(contents, ev); err != nil {
			return fmt.Errorf("marshalling event: %w", err)
		}
		if _, err := f.WriteString(contents.String() + "\n"); err != nil {
			return fmt.Errorf("writing string: %w", err)
		}
	}
	handler.logLock.Unlock()
	return nil
}

// SaveLastLog writes the output from the previous run to the specified filepath
func SaveLastLog(fp string) error {

View on GitHub (pinned to a1189de023)

Solutions

1. Append a filename if the destination is a directory path
2. Check that the filesystem is not read-only (mount | grep <path>) and pick a writable location
3. Verify write permission on the directory for the current user (ls -ld)
4. Inspect the wrapped syscall error for the precise errno

Example fix

// before
v2event.SaveEventsToFile("/mnt/ro-volume/logs/")
// after
v2event.SaveEventsToFile("/mnt/rw-volume/logs/events.json")

if info, err := os.Stat(fp); err == nil && info.IsDir() {
    return fmt.Errorf("v2 event log path %q is a directory", fp)
}

if err := v2event.SaveEventsToFile(fp); err != nil {
    if strings.Contains(err.Error(), "opening ") {
        fallback := filepath.Join(os.TempDir(), "skaffold-v2-events.json")
        log.Warnf("falling back to %s: %v", fallback, err)
        return v2event.SaveEventsToFile(fallback)
    }
    return err
}

When it happens

Trigger: The target path resolves to an existing directory (EISDIR); the parent is unwritable despite existing (EACCES); path exceeds NAME_MAX; the target is on a read-only filesystem where MkdirAll succeeded because the directory already existed but creating a new file inside fails (EROFS).

Common situations: Passing a directory path without a filename; on read-only filesystems where the directory already exists so MkdirAll succeeds but opening a new file fails; SELinux/AppArmor policies blocking creation.

Understand the failure class

Background: Permission denied / not authorized / 403 Forbidden: access-control rejections when the caller lacks the required role, grant, or ownership — this error's family across 18 libraries.

Related errors

• opening %s: %w
• unable to create directory %q: %w
• unable to create directory %q: %w
• writing string: %w
• writing string: %w

AI-assisted analysis of GoogleContainerTools/skaffold@a1189de023 (2026-09-05). Data as JSON: /api/errors/06487bdebe5b51d8. Report an issue: GitHub.