wtfutil/wtf · warning

could not get disk usage: %w

Error message

could not get disk usage: %w

What it means

getSystemInfo calls cli.DiskUsage(ctx, types.DiskUsageOptions{}); a failure is stringified into the widget buffer as "could not get disk usage". The Docker /system/df call failed even though Info may have succeeded, so the daemon connection works but the disk-usage API call does not.

Source

Thrown at modules/docker/client.go:22

	"context"
	"fmt"
	"sort"
	"strings"

	"github.com/docker/docker/api/types"
	"github.com/docker/docker/api/types/container"
	"github.com/dustin/go-humanize"
)

func (widget *Widget) getSystemInfo() string {
	info, err := widget.cli.Info(context.Background())
	if err != nil {
		return fmt.Errorf("could not get docker system info: %w", err).Error()
	}

	diskUsage, err := widget.cli.DiskUsage(context.Background(), types.DiskUsageOptions{})
	if err != nil {
		return fmt.Errorf("could not get disk usage: %w", err).Error()
	}

	var duContainer int64
	for _, c := range diskUsage.Containers {
		duContainer += c.SizeRw
	}
	var duImg int64
	for _, im := range diskUsage.Images {
		duImg += im.Size
	}
	var duVol int64
	for _, v := range diskUsage.Volumes {
		duVol += v.UsageData.Size
	}

	sysInfo := []struct {
		name  string
		value string

View on GitHub (pinned to bb838c1ccb)

Solutions

1. Run docker system df manually to confirm the daemon supports and completes the call.
2. Let the client negotiate the API version (remove explicit version pinning in client.NewClientWithOpts).
3. Retry the call; transient daemon load can cause one-off failures.
4. Update the docker/docker client library to match your Engine version.

Example fix

// before
diskUsage, err := widget.cli.DiskUsage(context.Background(), types.DiskUsageOptions{})
if err != nil {
	return fmt.Errorf("could not get disk usage: %w", err).Error()
}
// after
diskUsage, err := widget.cli.DiskUsage(context.Background(), types.DiskUsageOptions{})
if err != nil {
	return fmt.Errorf("could not get disk usage: %w", err).Error() // fallback: show container stats only
}

// Verify daemon supports disk usage before calling
out, err := exec.Command("docker", "system", "df", "--format", "json").Output()
if err != nil {
	// skip DiskUsage section of the widget
}

func isDiskUsageError(err error) bool {
	return err != nil && strings.Contains(err.Error(), "disk usage")
}

diskUsage, err := widget.cli.DiskUsage(ctx, types.DiskUsageOptions{})
if err != nil {
	widget.displayBuffer = "disk usage unavailable: " + err.Error()
	return // fall back to container-only display
}

When it happens

Trigger: cli.DiskUsage fails: daemon version older than the DiskUsageOptions API expects, connection dropped between calls, daemon busy/OOM, or API version negotiation mismatch between the docker client library and the daemon.

Common situations: Docker Engine upgraded/downgraded while the app pins a specific API version, very large daemon making /system/df time out, or permission-restricted endpoints on remote daemons.

Related errors

• could not get docker system info: %w
• could not get container list: %w
• could not create client: %w
• invalid app index selected
• cannot expand user-specific home dir

AI-assisted analysis of wtfutil/wtf@bb838c1ccb (2026-09-03). Data as JSON: /api/errors/4002675a55742c3e. Report an issue: GitHub.