fix(cmd/gpud): clean up "gpud down" logs (#41)

Signed-off-by: Gyuho Lee <[email protected]>

cmd/gpud/command/down.go

@@ -4,9 +4,10 @@ import (
 	"fmt"
 	"os"
 
-	"github.com/urfave/cli"
-
+	"github.com/leptonai/gpud/pkg/systemd"
 	pkgupdate "github.com/leptonai/gpud/pkg/update"
+
+	"github.com/urfave/cli"
 )
 
 func cmdDown(cliContext *cli.Context) error {
@@ -16,16 +17,26 @@ func cmdDown(cliContext *cli.Context) error {
 	}
 	if err := pkgupdate.RequireRoot(); err != nil {
 		fmt.Printf("%s %q requires root to stop gpud (if not run by systemd, manually kill the process with 'pidof gpud')\n", warningSign, bin)
-		return err
+		os.Exit(1)
 	}
 	if err := pkgupdate.SystemctlExists(); err != nil {
 		fmt.Printf("%s requires systemd: %v (if not run by systemd, manually kill the process with 'pidof gpud')\n", warningSign, err)
-		return err
+		os.Exit(1)
+	}
+
+	active, err := systemd.IsActive("gpud.service")
+	if err != nil {
+		fmt.Printf("%s failed to check if gpud is running: %v\n", warningSign, err)
+		os.Exit(1)
+	}
+	if !active {
+		fmt.Printf("%s gpud is not running (no-op)\n", checkMark)
+		os.Exit(0)
 	}
 
 	if err := pkgupdate.StopSystemdUnit(); err != nil {
 		fmt.Printf("%s failed to stop systemd unit 'gpud.service': %v\n", warningSign, err)
-		return err
+		os.Exit(1)
 	}
 
 	fmt.Printf("%s successfully stopped gpud\n", checkMark)