Fix/ping rover ip mdns

roverctl/src/commands/prechecks/prechecks.go

@@ -2,8 +2,10 @@ package command_prechecks
 
 import (
 	"fmt"
+	"strings"
 
 	"github.com/VU-ASE/rover/roverctl/src/configuration"
+	"github.com/VU-ASE/rover/roverctl/src/utils"
 	view_incompatible "github.com/VU-ASE/rover/roverctl/src/views/incompatible"
 
 	"github.com/spf13/cobra"
@@ -28,6 +30,12 @@ func Perform(cmd *cobra.Command, args []string, roverIndex int, roverdHost strin
 		// Pad number to two digits and use mDNS to resolve the rover's hostname
 		host = fmt.Sprintf("rover%02d.local", roverIndex)
 		// host = fmt.Sprintf("192.168.0.%d", roverIndex+100)
+
+		if strings.HasSuffix(host, ".local") {
+			if ip, err := utils.ResolveHostWithPing(host); err == nil {
+				host = ip
+			}
+		}
 	}
 
 	// Create connection

roverctl/src/utils/mdns.go

@@ -0,0 +1,60 @@
+package utils
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"os/exec"
+	"regexp"
+	"time"
+	"runtime"
+)
+
+// A regular expression to match IPv4 addresses in ping output
+var theIPv4Regex = regexp.MustCompile(`\((\d+\.\d+\.\d+\.\d+)\)`)
+
+func ResolveHostWithPing(host string) (string, error) {
+	// We use a context with timeout to avoid hanging indefinitely on the ping command
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancel()
+
+	// We prepare the ping command based on what OS is currently running roverctl
+	args := pingArgs(host)
+	cmd := exec.CommandContext(ctx, "ping", args...)
+
+	// Capture the output
+	var out bytes.Buffer
+	cmd.Stdout = &out
+	cmd.Stderr = &out
+
+	// Run the ping command, but do not return an error yet
+	// Since ping might fail even if mDNS resolution worked
+	// We will check the output for an IP address, and if we cannot find one, we return an error
+	if err := cmd.Run(); err != nil {
+		_ = err
+	}
+
+	// Search the output for an IPv4 address
+	matches := theIPv4Regex.FindStringSubmatch(out.String())
+	if len(matches) >= 2 {
+		return matches[1], nil
+	}
+
+	// If we reach here, we could not find an IP address in the ping output
+	return "", fmt.Errorf("could not resolve host %s via ping, output: %s", host, out.String())
+}
+
+func pingArgs(host string) []string {
+	// Different OSes have different arguments for ping
+	switch runtime.GOOS {
+		// MacOS
+		case "darwin":
+			return []string{"-c", "1", "-W", "1000", host}
+		// Linux
+		default:
+			return []string{"-c", "1", "-w", "1", host}
+	}
+}
+
+
+