Add pre-flight checks for e2e binary dependencies

Author: SamNet-dev

cmd/chain.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"os/exec"
 	"strconv"
 	"strings"
 	"time"
@@ -173,6 +174,26 @@ func runChain(cmd *cobra.Command, args []string) error {
 		configs = append(configs, cfg)
 	}
 
+	// Pre-flight: check required binaries for e2e steps
+	for _, cfg := range configs {
+		switch cfg.name {
+		case "e2e/dnstt", "doh/e2e":
+			if _, err := exec.LookPath("dnstt-client"); err != nil {
+				return fmt.Errorf("step %q requires dnstt-client in PATH (not found)", cfg.name)
+			}
+			if _, err := exec.LookPath("curl"); err != nil {
+				return fmt.Errorf("step %q requires curl in PATH (not found)", cfg.name)
+			}
+		case "e2e/slipstream":
+			if _, err := exec.LookPath("slipstream-client"); err != nil {
+				return fmt.Errorf("step %q requires slipstream-client in PATH (not found)", cfg.name)
+			}
+			if _, err := exec.LookPath("curl"); err != nil {
+				return fmt.Errorf("step %q requires curl in PATH (not found)", cfg.name)
+			}
+		}
+	}
+
 	// Shared port pool for e2e steps
 	ports := scanner.PortPool(portBase, workers)
 

cmd/scan.go

@@ -3,6 +3,7 @@ package main
 import (
 	"fmt"
 	"os"
+	"os/exec"
 	"sort"
 	"strings"
 	"time"
@@ -70,6 +71,23 @@ func runScan(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
+	// Pre-flight: verify required binaries before wasting time scanning
+	if pubkey != "" {
+		if _, err := exec.LookPath("dnstt-client"); err != nil {
+			return fmt.Errorf("--pubkey requires dnstt-client in PATH (not found)")
+		}
+	}
+	if certPath != "" {
+		if _, err := exec.LookPath("slipstream-client"); err != nil {
+			return fmt.Errorf("--cert requires slipstream-client in PATH (not found)")
+		}
+	}
+	if (pubkey != "" || certPath != "") {
+		if _, err := exec.LookPath("curl"); err != nil {
+			return fmt.Errorf("e2e tests require curl in PATH (not found)")
+		}
+	}
+
 	dur := time.Duration(timeout) * time.Second
 	needE2E := pubkey != "" || certPath != ""
 	var ports chan int