Phase 2 hardening: binary secret handling, tool checks, input validation, verbose flag, diff scroll

internal/kubeexec/kubeexec.go

@@ -19,13 +19,16 @@ import (
 )
 
 func runOutput(name string, args ...string) (string, error) {
+	logCmd(name, args...)
 	cmd := exec.Command(name, args...)
 	var stdout, stderr strings.Builder
 	cmd.Stdout = &stdout
 	cmd.Stderr = &stderr
 	err := cmd.Run()
 	if err != nil {
-		msg := fmt.Sprintf("%s %s failed: %v", name, strings.Join(args, " "), err)
+		logErr(name, err)
+		prefix := fmt.Sprintf("%s %s failed: %v", name, strings.Join(args, " "), err)
+		msg := prefix
 		if s := strings.TrimSpace(stderr.String()); s != "" {
 			msg += "\n" + s
 		}
@@ -34,7 +37,9 @@ func runOutput(name string, args ...string) (string, error) {
 		}
 		return "", fmt.Errorf("%s", msg)
 	}
-	return strings.TrimSpace(stdout.String()), nil
+	out := strings.TrimSpace(stdout.String())
+	logOutput(name, out)
+	return out, nil
 }
 
 // kubectlArgs prepends a --context flag when context is non-empty.
@@ -172,3 +177,13 @@ func RunAWSLogin(loginCommand string) *exec.Cmd {
 	}
 	return exec.Command(parts[0], parts[1:]...)
 }
+
+// CheckTool verifies that a named executable is available in PATH.
+// Returns nil if found, or a descriptive error if not.
+func CheckTool(name string) error {
+	_, err := exec.LookPath(name)
+	if err != nil {
+		return fmt.Errorf("%q not found in PATH — please install it first", name)
+	}
+	return nil
+}

internal/kubeexec/log.go

@@ -0,0 +1,56 @@
+package kubeexec
+
+import (
+	"fmt"
+	"io"
+	"strings"
+	"sync"
+)
+
+var (
+	verbose bool
+	logOut  io.Writer = io.Discard
+	mu      sync.Mutex
+)
+
+// SetVerbose enables or disables debug logging of executed commands.
+// When enabled, commands and their outputs are written to the provided
+// writer (typically os.Stderr). When disabled (the default), all logging
+// is discarded.
+func SetVerbose(enabled bool, w io.Writer) {
+	mu.Lock()
+	defer mu.Unlock()
+	verbose = enabled
+	if w != nil {
+		logOut = w
+	}
+}
+
+func logCmd(name string, args ...string) {
+	mu.Lock()
+	defer mu.Unlock()
+	if !verbose {
+		return
+	}
+	fmt.Fprintf(logOut, "[cmd] %s %s\n", name, strings.Join(args, " "))
+}
+
+func logOutput(name string, output string) {
+	mu.Lock()
+	defer mu.Unlock()
+	if !verbose {
+		return
+	}
+	if output != "" {
+		fmt.Fprintf(logOut, "[out] %s: %s\n", name, output)
+	}
+}
+
+func logErr(name string, err error) {
+	mu.Lock()
+	defer mu.Unlock()
+	if !verbose {
+		return
+	}
+	fmt.Fprintf(logOut, "[err] %s: %v\n", name, err)
+}