refactor(logs): update log formatting for systemd services and handle merging in the client

cmd/uncloud/machine/logs.go

@@ -16,35 +16,39 @@ func NewLogsCommand() *cobra.Command {
 	var options logs.Options
 
 	cmd := &cobra.Command{
-		Use:     "logs [UNIT...]",
+		Use:     "logs [SERVICE...]",
 		Aliases: []string{"log"},
 		Short:   "View systemd service logs.",
-		Long: `View logs from all replicas of the specified units(s) (uncloud, docker or uncloud-corrosion) across all machines in the cluster.
+		Long: `View logs from the specified systemd service(s) across all machines in the cluster.
+Use -m to restrict to specific machines.
 
-If no units are specified, streams logs from the uncloud unit.`,
-		Example: `  # View recent logs for a system service.
-  uc logs uncloud
+Supported services:
+  uncloud            the Uncloud daemon
+  docker             the Docker daemon
+  uncloud-corrosion  the Corrosion distributed state store
+
+If no services are specified, streams logs from the uncloud service.`,
+		Example: `  # View recent logs for the uncloud service.
+  uc machine logs
+  uc machine logs uncloud
 
   # Stream logs in real-time (follow mode).
-  uc logs -f uncloud
+  uc machine logs -f uncloud
 
   # View logs from multiple services.
-  uc logs web uncloud docker
+  uc machine logs uncloud docker uncloud-corrosion
 
-  # View logs from uncloud
-  uc logs
-
-  # Show last 20 lines per replica (default is 100).
-  uc logs -n 20 docker
+  # Show last 20 lines per machine (default is 100).
+  uc machine logs -n 20 docker
 
   # Show all logs without line limit.
-  uc logs -n all docker
+  uc machine logs -n all docker
 
   # View logs from a specific time range.
-  uc logs --since 3h --until 1h30m docker
+  uc machine logs --since 3h --until 1h30m docker
 
-  # View logs only from replicas running on specific machines.
-  uc logs -m machine1,machine2 docker corrosion`,
+  # View logs only from specific machines.
+  uc machine logs -m machine1,machine2 uncloud uncloud-corrosion`,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			uncli := cmd.Context().Value("cli").(*cli.CLI)
 			return runLogs(cmd.Context(), uncli, args, options)
@@ -62,7 +66,7 @@ func runLogs(ctx context.Context, uncli *cli.CLI, units []string, opts logs.Opti
 
 	for _, unit := range units {
 		if !journal.ValidUnit(unit) {
-			return fmt.Errorf("invalid unit '%s'", unit)
+			return fmt.Errorf("invalid systemd service '%s'", unit)
 		}
 	}
 
@@ -85,8 +89,10 @@ func runLogs(ctx context.Context, uncli *cli.CLI, units []string, opts logs.Opti
 		Machines: cli.ExpandCommaSeparatedValues(opts.Machines),
 	}
 
-	// Fetch machine names for all machines we want the unit logs from.
-	machines, err := c.ListMachines(ctx, &api.MachineFilter{NamesOrIDs: opts.Machines})
+	// Resolve machine records for the formatter's column width computation.
+	machines, err := c.ListMachines(ctx, &api.MachineFilter{
+		NamesOrIDs: logsOpts.Machines,
+	})
 	if err != nil {
 		return fmt.Errorf("list machines: %w", err)
 	}
@@ -95,23 +101,22 @@ func runLogs(ctx context.Context, uncli *cli.CLI, units []string, opts logs.Opti
 		machineNames = append(machineNames, m.Machine.Name)
 	}
 
-	// Collect log streams from the units on the machine machines.
-	unitStreams := make([]<-chan api.ServiceLogEntry, 0, len(units)+len(machines))
-
-	for _, machine := range machineNames {
-		for _, unit := range units {
-			ch, err := c.MachineLogs(ctx, machine, unit, logsOpts)
-			if err != nil {
-				return fmt.Errorf("stream logs for systemd service '%s': %w", unit, err)
-			}
-			unitStreams = append(unitStreams, ch)
+	// Collect one log stream per unit. MachineLogs merges across machines internally.
+	unitStreams := make([]<-chan api.ServiceLogEntry, 0, len(units))
+	for _, unit := range units {
+		ch, err := c.MachineLogs(ctx, unit, logsOpts)
+		if err != nil {
+			return fmt.Errorf("stream logs for systemd service '%s': %w", unit, err)
 		}
+		unitStreams = append(unitStreams, ch)
 	}
 
 	var stream <-chan api.ServiceLogEntry
-	if len(units) == 1 {
+	if len(unitStreams) == 1 {
 		stream = unitStreams[0]
 	} else {
+		// Each MachineLogs stream already runs its own inner merger with stall detection,
+		// so the outer merger across units skips it to avoid duplicate warnings.
 		merger := client.NewLogMerger(unitStreams, client.LogMergerOptions{})
 		stream = merger.Stream()
 	}