refactor(grpc-proxy): use Metadata.Err() method to get upstream error for a broadcasted request

api/pb/common.go

@@ -4,8 +4,16 @@ import (
 	"bytes"
 	"fmt"
 	"net/netip"
+
+	"google.golang.org/grpc/status"
 )
 
+// Err returns the upstream error, preserving its gRPC status code.
+// It returns nil for nil metadata or an absent or successful status.
+func (m *Metadata) Err() error {
+	return status.ErrorProto(m.GetStatus())
+}
+
 func NewIP(addr netip.Addr) *IP {
 	// MarshalBinary always returns a nil error.
 	ip, _ := addr.MarshalBinary()

cmd/uc/image/ls.go

@@ -103,7 +103,7 @@ func list(ctx context.Context, uncli *cli.CLI, opts listOptions) error {
 	var rows []imageRow
 
 	for _, machineImages := range clusterImages {
-		if err := machineImages.Error(); err != nil {
+		if err := machineImages.Metadata.Err(); err != nil {
 			tui.PrintWarning(fmt.Sprintf("failed to list images on machine '%s': %s",
 				machineImages.Metadata.MachineName, err))
 			continue

cmd/uc/machine/rtt.go

@@ -54,8 +54,8 @@ func rtt(ctx context.Context, uncli *cli.CLI) error {
 			tui.PrintWarning("metadata is missing in response from unknown server")
 			continue
 		}
-		if m.Metadata.Error != "" {
+		if err := m.Metadata.Err(); err != nil {
-			tui.PrintWarning(fmt.Sprintf("failed to inspect machine '%s': %s", m.Metadata.MachineName, m.Metadata.Error))
+			tui.PrintWarning(fmt.Sprintf("failed to inspect machine '%s': %s", m.Metadata.MachineName, err))
 			continue
 		}
 		if m.Machine == nil {

cmd/uc/ps.go

@@ -207,9 +207,9 @@ func collectContainers(ctx context.Context, cli *client.Client) ([]containerInfo
 
 		machineName := msc.Metadata.MachineName
 
-		if msc.Metadata.Error != "" {
+		if err := msc.Metadata.Err(); err != nil {
 			tui.PrintWarning(fmt.Sprintf("failed to list service containers on machine %s: %s",
-				machineName, msc.Metadata.Error))
+				machineName, err))
 			continue
 		}
 

internal/machine/docker/client.go

@@ -167,7 +167,7 @@ func (c *Client) ListContainers(ctx context.Context, opts container.ListOptions)
 	machineContainers := make([]MachineContainers, len(resp.Messages))
 	for i, msg := range resp.Messages {
 		machineContainers[i].Metadata = msg.Metadata
-		if msg.Metadata != nil && msg.Metadata.Error != "" {
+		if msg.Metadata.Err() != nil {
 			continue
 		}
 
@@ -258,7 +258,7 @@ func (c *Client) InspectImage(ctx context.Context, id string) ([]api.MachineImag
 
 	notFoundCount := 0
 	for _, msg := range resp.Messages {
-		if msg.Metadata != nil && msg.Metadata.Status != nil && codes.Code(msg.Metadata.Status.Code) == codes.NotFound {
+		if status.Code(msg.Metadata.Err()) == codes.NotFound {
 			notFoundCount++
 		}
 	}
@@ -269,7 +269,7 @@ func (c *Client) InspectImage(ctx context.Context, id string) ([]api.MachineImag
 	images := make([]api.MachineImage, len(resp.Messages))
 	for i, msg := range resp.Messages {
 		images[i].Metadata = msg.Metadata
-		if msg.Metadata != nil && msg.Metadata.Error != "" {
+		if msg.Metadata.Err() != nil {
 			continue
 		}
 
@@ -312,7 +312,7 @@ func parseRemoteImageMessage(msg *pb.RemoteImage) (api.MachineRemoteImage, error
 	mri := api.MachineRemoteImage{
 		Metadata: msg.Metadata,
 	}
-	if msg.Metadata != nil && msg.Metadata.Error != "" {
+	if msg.Metadata.Err() != nil {
 		return mri, nil
 	}
 
@@ -393,7 +393,7 @@ func (c *Client) ListVolumes(ctx context.Context, opts volume.ListOptions) ([]Ma
 	machineVolumes := make([]MachineVolumes, len(resp.Messages))
 	for i, msg := range resp.Messages {
 		machineVolumes[i].Metadata = msg.Metadata
-		if msg.Metadata != nil && msg.Metadata.Error != "" {
+		if msg.Metadata.Err() != nil {
 			continue
 		}
 
@@ -472,7 +472,7 @@ func (c *Client) ListServiceContainers(
 	machineContainers := make([]MachineServiceContainers, len(resp.Messages))
 	for i, msg := range resp.Messages {
 		machineContainers[i].Metadata = msg.Metadata
-		if msg.Metadata != nil && msg.Metadata.Error != "" {
+		if msg.Metadata.Err() != nil {
 			continue
 		}
 

pkg/api/image.go

@@ -1,7 +1,6 @@
 package api
 
 import (
-	"errors"
 	"slices"
 
 	"github.com/distribution/reference"
@@ -25,14 +24,6 @@ type MachineImages struct {
 	ContainerdStore bool
 }
 
-// Error returns a non-nil error if listing images on this machine failed.
-func (mi MachineImages) Error() error {
-	if mi.Metadata != nil && mi.Metadata.Error != "" {
-		return errors.New(mi.Metadata.Error)
-	}
-	return nil
-}
-
 // ImageFilter defines criteria to filter images in ListImages.
 type ImageFilter struct {
 	// Machines filters images to those present on the specified machines (names or IDs).

pkg/client/image.go

@@ -92,7 +92,7 @@ func (cli *Client) ListImages(ctx context.Context, filter api.ImageFilter) ([]ap
 			ContainerdStore: msg.ContainerdStore,
 		}
 
-		if msg.Metadata.Error == "" && len(msg.Images) > 0 {
+		if msg.Metadata.Err() == nil && len(msg.Images) > 0 {
 			if err = json.Unmarshal(msg.Images, &mi.Images); err != nil {
 				return nil, fmt.Errorf("unmarshal images: %w", err)
 			}
@@ -104,6 +104,7 @@ func (cli *Client) ListImages(ctx context.Context, filter api.ImageFilter) ([]ap
 	return machineImages, nil
 }
 
+// TODO: move PushImageOptions to api package and include PushImage in ImageClient interface.
 type PushImageOptions struct {
 	// AllMachines pushes the image to all machines in the cluster. Takes precedence over Machines field.
 	AllMachines bool
@@ -215,7 +216,7 @@ func (cli *Client) pushImageToMachine(
 		Name:     "%invalid-name-to-only-check-store-type%",
 	})
 	if err == nil {
-		err = images[0].Error()
+		err = images[0].Metadata.Err()
 	}
 	if err != nil {
 		return fmt.Errorf("check Docker image store type on machine '%s': %w", machine.Name, err)

pkg/client/service.go

@@ -125,10 +125,10 @@ func (cli *Client) InspectService(ctx context.Context, nameOrID string) (api.Ser
 			continue
 		}
 
-		if mc.Metadata.Error != "" {
+		if err := mc.Metadata.Err(); err != nil {
 			// TODO: return failed machines in the response.
 			tui.PrintWarning(fmt.Sprintf("failed to list containers on machine '%s': %s",
-				mc.Metadata.MachineName, mc.Metadata.Error))
+				mc.Metadata.MachineName, err))
 			continue
 		}
 
@@ -333,10 +333,10 @@ func (cli *Client) ListServices(ctx context.Context) ([]api.Service, error) {
 	// Group containers by service ID using the broadcast results.
 	servicesByID := make(map[string]api.Service)
 	for _, mc := range machineContainers {
-		if mc.Metadata.Error != "" {
+		if err := mc.Metadata.Err(); err != nil {
 			// TODO: return failed machines in the response.
 			tui.PrintWarning(fmt.Sprintf("failed to list containers on machine '%s': %s",
-				mc.Metadata.MachineName, mc.Metadata.Error))
+				mc.Metadata.MachineName, err))
 			continue
 		}
 

pkg/client/volume.go

@@ -70,10 +70,10 @@ func (cli *Client) ListVolumes(ctx context.Context, filter *api.VolumeFilter) ([
 			continue
 		}
 
-		if mv.Metadata.Error != "" {
+		if err := mv.Metadata.Err(); err != nil {
 			// TODO: return failed machines in the response.
 			tui.PrintWarning(fmt.Sprintf("failed to list volumes on machine '%s': %s", mv.Metadata.MachineName,
-				mv.Metadata.Error))
+				err))
 			continue
 		}