feat(logs): update 'uc logs' command to support filtering by service/container

cmd/uncloud/internal/logs/formatter.go

@@ -3,6 +3,7 @@ package logs
 import (
 	"errors"
 	"fmt"
+	"image/color"
 	"os"
 	"slices"
 	"strings"
@@ -75,7 +76,7 @@ func (f *Formatter) formatMachine(name string) string {
 			i = len(f.machineNames) - 1
 		}
 
-		style = style.Foreground(Palette[i%len(Palette)])
+		style = style.Foreground(palette[i%len(palette)])
 	}
 
 	return style.Render(name)
@@ -93,7 +94,7 @@ func (f *Formatter) formatService(serviceName, containerID string) string {
 			i = len(f.serviceNames) - 1
 		}
 
-		styleService = styleService.Foreground(Palette[i%len(Palette)])
+		styleService = styleService.Foreground(palette[i%len(palette)])
 	}
 
 	// Journal logs are unit-scoped and have no container ID.
@@ -165,3 +166,17 @@ func (f *Formatter) PrintError(entry api.ServiceLogEntry) {
 	style := lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("11")) // Bold bright yellow.
 	fmt.Fprintln(os.Stderr, style.Render(msg))
 }
+
+// palette is available colors for machine/service differentiation.
+var palette = []color.Color{
+	lipgloss.BrightGreen,
+	lipgloss.BrightYellow,
+	lipgloss.BrightBlue,
+	lipgloss.BrightMagenta,
+	lipgloss.BrightCyan,
+	lipgloss.Green,
+	lipgloss.Yellow,
+	lipgloss.Blue,
+	lipgloss.Magenta,
+	lipgloss.Cyan,
+}

cmd/uncloud/internal/logs/logs.go

@@ -2,10 +2,9 @@ package logs
 
 import (
 	"fmt"
-	"image/color"
 	"strconv"
+	"strings"
 
-	"charm.land/lipgloss/v2"
 	"github.com/spf13/pflag"
 )
 
@@ -59,16 +58,59 @@ func Tail(tail string) (int, error) {
 	return tailInt, nil
 }
 
-// Available colors for machine/service differentiation.
-var Palette = []color.Color{
-	lipgloss.BrightGreen,
-	lipgloss.BrightYellow,
-	lipgloss.BrightBlue,
-	lipgloss.BrightMagenta,
-	lipgloss.BrightCyan,
-	lipgloss.Green,
-	lipgloss.Yellow,
-	lipgloss.Blue,
-	lipgloss.Magenta,
-	lipgloss.Cyan,
+// ServiceArg pairs a service name with the list of container filters parsed from `uc service logs` arguments.
+// An empty Containers slice means "stream logs from all containers of this service".
+type ServiceArg struct {
+	Service    string
+	Containers []string
+}
+
+// ParseServiceArgs groups raw `uc service logs` positional arguments into per-service entries,
+// preserving first-seen order. Each argument is either a service name (e.g. "web") or a
+// service/container reference (e.g. "web/61d57fd3428f").
+// Arguments for the same service are merged: if any argument for a service lacks a container suffix, all containers
+// of that service are streamed regardless of any other service/container arguments for it.
+func ParseServiceArgs(args []string) ([]ServiceArg, error) {
+	indexByService := make(map[string]int, len(args))
+	allContainers := make(map[string]bool, len(args))
+	result := make([]ServiceArg, 0, len(args))
+
+	for _, arg := range args {
+		arg = strings.TrimSpace(arg)
+		if arg == "" {
+			return nil, fmt.Errorf("empty service argument")
+		}
+
+		service, container, hasSlash := strings.Cut(arg, "/")
+		if service == "" {
+			return nil, fmt.Errorf("invalid service argument '%s': service name is empty", arg)
+		}
+		if hasSlash && container == "" {
+			return nil, fmt.Errorf("invalid service argument '%s': container name or ID is empty", arg)
+		}
+
+		idx, seen := indexByService[service]
+		if !seen {
+			entry := ServiceArg{Service: service}
+			if hasSlash {
+				entry.Containers = []string{container}
+			} else {
+				allContainers[service] = true
+			}
+			result = append(result, entry)
+			indexByService[service] = len(result) - 1
+			continue
+		}
+
+		if !hasSlash {
+			result[idx].Containers = nil
+			allContainers[service] = true
+			continue
+		}
+		if !allContainers[service] {
+			result[idx].Containers = append(result[idx].Containers, container)
+		}
+	}
+
+	return result, nil
 }

cmd/uncloud/service/logs.go

@@ -20,11 +20,14 @@ func NewLogsCommand(groupID string) *cobra.Command {
 	var options logs.Options
 
 	cmd := &cobra.Command{
-		Use:     "logs [SERVICE...]",
+		Use:     "logs [SERVICE[/CONTAINER]...]",
 		Aliases: []string{"log"},
 		Short:   "View service logs.",
 		Long: `View logs from all replicas of the specified service(s) across all machines in the cluster.
 
+To view logs from specific replicas (containers) within a service, use the SERVICE/CONTAINER form,
+where CONTAINER is a container name, full ID, or unique ID prefix.
+
 If no services are specified, streams logs from all services defined in the Compose file
 (compose.yaml by default or the file(s) specified with --file).`,
 		Example: `  # View recent logs for a service.
@@ -48,6 +51,9 @@ If no services are specified, streams logs from all services defined in the Comp
   # View logs from a specific time range.
   uc logs --since 3h --until 1h30m web
 
+  # View logs only from specific replicas (containers).
+  uc logs web/61d57fd3428f api/2f60
+
   # View logs only from replicas running on specific machines.
   uc logs -m machine1,machine2 web api`,
 		RunE: func(cmd *cobra.Command, args []string) error {
@@ -64,10 +70,15 @@ If no services are specified, streams logs from all services defined in the Comp
 	return cmd
 }
 
-func runLogs(ctx context.Context, uncli *cli.CLI, serviceNames []string, opts logs.Options) error {
+func runLogs(ctx context.Context, uncli *cli.CLI, args []string, opts logs.Options) error {
+	serviceArgs, err := logs.ParseServiceArgs(args)
+	if err != nil {
+		return err
+	}
+
 	// If no services specified, try to load them from the Compose file(s).
 	fromCompose := false
-	if len(serviceNames) == 0 {
+	if len(serviceArgs) == 0 {
 		fromCompose = true
 		project, err := compose.LoadProject(ctx, opts.Files)
 		if err != nil {
@@ -77,10 +88,15 @@ func runLogs(ctx context.Context, uncli *cli.CLI, serviceNames []string, opts lo
 		uncli.SetClusterContextIfUnset(compose.ClusterContext(project))
 
 		// View logs for all services, including disabled by inactive profiles.
-		serviceNames = append(project.ServiceNames(), project.DisabledServiceNames()...)
-		if len(serviceNames) == 0 {
+		composeServices := append(project.ServiceNames(), project.DisabledServiceNames()...)
+		if len(composeServices) == 0 {
 			return errors.New("no services found in Compose file(s)")
 		}
+
+		serviceArgs = make([]logs.ServiceArg, len(composeServices))
+		for i, name := range composeServices {
+			serviceArgs[i] = logs.ServiceArg{Service: name}
+		}
 	}
 
 	// Parse tail option.
@@ -95,7 +111,7 @@ func runLogs(ctx context.Context, uncli *cli.CLI, serviceNames []string, opts lo
 	}
 	defer c.Close()
 
-	logsOpts := api.ServiceLogsOptions{
+	baseOpts := api.ServiceLogsOptions{
 		Follow:   opts.Follow,
 		Tail:     tail,
 		Since:    opts.Since,
@@ -106,20 +122,23 @@ func runLogs(ctx context.Context, uncli *cli.CLI, serviceNames []string, opts lo
 	// Collect log streams from all services. When service names come from a Compose file,
 	// skip the ones that are not found in the cluster (they may have been removed or not deployed yet).
 	machineIDsSet := mapset.NewSet[string]()
-	svcStreams := make([]<-chan api.ServiceLogEntry, 0, len(serviceNames))
+	svcStreams := make([]<-chan api.ServiceLogEntry, 0, len(serviceArgs))
 	var foundServices, notFoundServices []string
 
-	for _, serviceName := range serviceNames {
-		svc, ch, err := c.ServiceLogs(ctx, serviceName, logsOpts)
+	for _, sa := range serviceArgs {
+		svcOpts := baseOpts
+		svcOpts.Containers = sa.Containers
+
+		svc, ch, err := c.ServiceLogs(ctx, sa.Service, svcOpts)
 		if err != nil {
 			if errors.Is(err, api.ErrNotFound) && fromCompose {
-				notFoundServices = append(notFoundServices, serviceName)
+				notFoundServices = append(notFoundServices, sa.Service)
 				continue
 			}
-			return fmt.Errorf("stream logs for service '%s': %w", serviceName, err)
+			return fmt.Errorf("stream logs for service '%s': %w", sa.Service, err)
 		}
 		svcStreams = append(svcStreams, ch)
-		foundServices = append(foundServices, serviceName)
+		foundServices = append(foundServices, sa.Service)
 
 		machineIDs := svc.MachineIDs()
 		machineIDsSet.Append(machineIDs...)
@@ -130,7 +149,6 @@ func runLogs(ctx context.Context, uncli *cli.CLI, serviceNames []string, opts lo
 			return fmt.Errorf("stream logs for services defined in %s: no services found in the cluster",
 				strings.Join(opts.Files, ", "))
 		}
-		serviceNames = foundServices
 
 		for _, name := range notFoundServices {
 			tui.PrintWarning(fmt.Sprintf("service '%s' not found in the cluster, skipping", name))
@@ -138,7 +156,7 @@ func runLogs(ctx context.Context, uncli *cli.CLI, serviceNames []string, opts lo
 	}
 
 	var stream <-chan api.ServiceLogEntry
-	if len(serviceNames) == 1 {
+	if len(svcStreams) == 1 {
 		stream = svcStreams[0]
 	} else {
 		// Merge all service streams into a single sorted stream without stall detection as its handled per-service.
@@ -147,6 +165,8 @@ func runLogs(ctx context.Context, uncli *cli.CLI, serviceNames []string, opts lo
 	}
 
 	// Fetch machine names for all machines (machineIDsSet) service containers are running on.
+	// Note: this is the full set per service, not narrowed by --machine or per-container filters,
+	// so the formatter may pad columns wider than strictly needed when filters are active.
 	machines, err := c.ListMachines(ctx, &api.MachineFilter{NamesOrIDs: machineIDsSet.ToSlice()})
 	if err != nil {
 		return fmt.Errorf("list machines: %w", err)
@@ -156,7 +176,7 @@ func runLogs(ctx context.Context, uncli *cli.CLI, serviceNames []string, opts lo
 		machineNames = append(machineNames, m.Machine.Name)
 	}
 
-	formatter := logs.NewFormatter(machineNames, serviceNames, opts.UTC)
+	formatter := logs.NewFormatter(machineNames, foundServices, opts.UTC)
 
 	// Print merged logs.
 	for entry := range stream {

pkg/api/logs.go

@@ -46,12 +46,16 @@ func LogStreamTypeToProto(s LogStreamType) pb.LogEntry_StreamType {
 	}
 }
 
-// ServiceLogsOptions specifies parameters for ServiceLogs.
+// ServiceLogsOptions specifies parameters for ServiceLogs and MachineLogs.
 type ServiceLogsOptions struct {
 	Follow bool
 	Tail   int
 	Since  string
 	Until  string
+	// Containers filters logs to only include the specified service containers (names, full IDs,
+	// or unique ID prefixes). If empty, logs from all containers in the service are included.
+	// Ignored by MachineLogs.
+	Containers []string
 	// Machines filters logs to only include containers running on the specified machines (names or IDs).
 	// If empty, logs from all machines are included.
 	Machines []string

pkg/api/service.go

@@ -519,6 +519,29 @@ type MachineServiceContainer struct {
 	Container ServiceContainer
 }
 
+// FindContainer returns the service container by exact name, ID, or unique ID prefix.
+// Returns ErrNotFound if no container matches, or an error if an ID prefix matches more than one container.
+func (s *Service) FindContainer(nameOrID string) (MachineServiceContainer, error) {
+	var prefixMatches []MachineServiceContainer
+	for _, c := range append(s.Containers, s.HookContainers...) {
+		if c.Container.ID == nameOrID || c.Container.Name == nameOrID {
+			return c, nil
+		}
+		if strings.HasPrefix(c.Container.ID, nameOrID) {
+			prefixMatches = append(prefixMatches, c)
+		}
+	}
+
+	if len(prefixMatches) == 1 {
+		return prefixMatches[0], nil
+	}
+	if len(prefixMatches) > 1 {
+		return MachineServiceContainer{}, fmt.Errorf("multiple containers found with ID prefix '%s'", nameOrID)
+	}
+
+	return MachineServiceContainer{}, ErrNotFound
+}
+
 // MachineIDs returns a list of unique machine IDs where the service containers are running.
 func (s *Service) MachineIDs() []string {
 	ids := mapset.NewSet[string]()

pkg/client/container.go

@@ -256,26 +256,7 @@ func (cli *Client) InspectContainer(
 		return api.MachineServiceContainer{}, fmt.Errorf("inspect service: %w", err)
 	}
 
-	prefixMatchCandidates := []api.MachineServiceContainer{}
-	for _, c := range append(svc.Containers, svc.HookContainers...) {
-		if c.Container.ID == containerNameOrID ||
-			c.Container.Name == containerNameOrID {
-			return c, nil
-		}
-
-		if strings.HasPrefix(c.Container.ID, containerNameOrID) {
-			prefixMatchCandidates = append(prefixMatchCandidates, c)
-		}
-	}
-
-	if len(prefixMatchCandidates) == 1 {
-		return prefixMatchCandidates[0], nil
-	} else if len(prefixMatchCandidates) > 1 {
-		return api.MachineServiceContainer{}, fmt.Errorf(
-			"multiple containers found with ID prefix '%s'", containerNameOrID)
-	}
-
-	return api.MachineServiceContainer{}, api.ErrNotFound
+	return svc.FindContainer(containerNameOrID)
 }
 
 // StartContainer starts the specified container within the service.

pkg/client/logs.go

@@ -5,6 +5,8 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"maps"
+	"slices"
 
 	"github.com/docker/docker/pkg/stringid"
 	"github.com/psviderski/uncloud/internal/machine/api/pb"
@@ -24,11 +26,25 @@ func (cli *Client) ServiceLogs(
 		return svc, nil, fmt.Errorf("inspect service: %w", err)
 	}
 
-	allContainers := append(svc.Containers, svc.HookContainers...)
-	if len(allContainers) == 0 {
+	containers := append(svc.Containers, svc.HookContainers...)
+	if len(containers) == 0 {
 		return svc, nil, fmt.Errorf("no containers found for service: %s", serviceNameOrID)
 	}
 
+	if len(opts.Containers) > 0 {
+		selected := make(map[string]api.MachineServiceContainer, len(opts.Containers))
+		for _, nameOrID := range opts.Containers {
+			ctr, err := svc.FindContainer(nameOrID)
+			if err != nil {
+				return svc, nil, fmt.Errorf("find container '%s' in service '%s': %w",
+					nameOrID, serviceNameOrID, err)
+			}
+			selected[ctr.Container.ID] = ctr
+		}
+
+		containers = slices.Collect(maps.Values(selected))
+	}
+
 	machines, err := cli.ListMachines(ctx, &api.MachineFilter{
 		NamesOrIDs: opts.Machines,
 	})
@@ -36,8 +52,8 @@ func (cli *Client) ServiceLogs(
 		return svc, nil, fmt.Errorf("list machines: %w", err)
 	}
 
-	ctrStreams := make([]<-chan api.ServiceLogEntry, 0, len(allContainers))
-	for _, ctr := range allContainers {
+	ctrStreams := make([]<-chan api.ServiceLogEntry, 0, len(containers))
+	for _, ctr := range containers {
 		// Skip containers not running on the specified machines.
 		m := machines.FindByNameOrID(ctr.MachineID)
 		if len(opts.Machines) > 0 && m == nil {

test/e2e/service_test.go

@@ -2026,6 +2026,52 @@ func TestServiceLifecycle(t *testing.T) {
 		})
 		require.Error(t, err)
 		assert.Contains(t, err.Error(), "machines not found")
+
+		// Test filter logs by container.
+		targetCtr := svc.Containers[0].Container
+		expectedStdout := fmt.Sprintf("Hello from %s\n", targetCtr.Name)
+		expectedStderr := fmt.Sprintf("Hello stderr from %s\n", targetCtr.Name)
+
+		// Filter by full container ID.
+		_, ctrStream, err := cli.ServiceLogs(ctx, name, api.ServiceLogsOptions{
+			Containers: []string{targetCtr.ID},
+		})
+		require.NoError(t, err)
+		assert.Equal(t, []string{expectedStdout, expectedStderr}, collectLogs(ctrStream))
+
+		// Filter by container name.
+		_, ctrStream, err = cli.ServiceLogs(ctx, name, api.ServiceLogsOptions{
+			Containers: []string{targetCtr.Name},
+		})
+		require.NoError(t, err)
+		assert.Equal(t, []string{expectedStdout, expectedStderr}, collectLogs(ctrStream))
+
+		// Filter by short ID prefix (12 chars is Docker's standard short ID length).
+		_, ctrStream, err = cli.ServiceLogs(ctx, name, api.ServiceLogsOptions{
+			Containers: []string{targetCtr.ID[:12]},
+		})
+		require.NoError(t, err)
+		assert.Equal(t, []string{expectedStdout, expectedStderr}, collectLogs(ctrStream))
+
+		// Filter by multiple containers in the same service.
+		secondCtr := svc.Containers[1].Container
+		_, ctrStream, err = cli.ServiceLogs(ctx, name, api.ServiceLogsOptions{
+			Containers: []string{targetCtr.ID, secondCtr.ID},
+		})
+		require.NoError(t, err)
+		multiLogs := collectLogs(ctrStream)
+		require.Len(t, multiLogs, 4, "should have 4 log entries from 2 containers")
+		assert.Contains(t, multiLogs, expectedStdout)
+		assert.Contains(t, multiLogs, expectedStderr)
+		assert.Contains(t, multiLogs, fmt.Sprintf("Hello from %s\n", secondCtr.Name))
+		assert.Contains(t, multiLogs, fmt.Sprintf("Hello stderr from %s\n", secondCtr.Name))
+
+		// Test non-existent container filter returns error.
+		_, _, err = cli.ServiceLogs(ctx, name, api.ServiceLogsOptions{
+			Containers: []string{"non-existent-container"},
+		})
+		require.Error(t, err)
+		assert.ErrorContains(t, err, "container 'non-existent-container' in service 'test-service-logs': not found")
 	})
 
 	t.Run("internal DNS", func(t *testing.T) {