sic v2 client WP5: verbFor — runtime type + name -> the runtime verb (incus/docker/pct)

cmd/sic/addr.go

@@ -1,5 +1,7 @@
 package main
 
+import "fmt"
+
 func parseTarget(s string) (host string, hops []string) {
 	for i := 0; i < len(s); i++ {
 		if s[i] == '/' {
@@ -28,3 +30,16 @@ func splitHops(s string) []string {
 	hops = append(hops, s[start:])
 	return hops
 }
+
+func verbFor(runtime, name string) (string, error) {
+	switch runtime {
+	case "incus":
+		return "incus exec " + name + " --", nil
+	case "docker":
+		return "docker exec " + name, nil
+	case "pct":
+		return "pct exec " + name + " --", nil
+	default:
+		return "", fmt.Errorf("unknown runtime: %s", runtime)
+	}
+}

cmd/sic/verbfor_test.go

@@ -0,0 +1,29 @@
+package main
+
+import "testing"
+
+// WP5: verbFor maps a hop's runtime TYPE + container name to the runtime verb that enters it.
+// The inner-hop command is this verb with " sicd" appended (wrapHop does the append), so the
+// verb must end right where "sicd" should follow: incus/pct need the "--" argv separator,
+// docker exec does not. Unknown runtime is a hard error (fail-loud, never guess a verb).
+func TestVerbFor(t *testing.T) {
+	cases := []struct {
+		runtime, name, want string
+	}{
+		{"incus", "memory", "incus exec memory --"},
+		{"docker", "stash-stash-1", "docker exec stash-stash-1"},
+		{"pct", "107", "pct exec 107 --"},
+	}
+	for _, tc := range cases {
+		got, err := verbFor(tc.runtime, tc.name)
+		if err != nil {
+			t.Fatalf("verbFor(%q,%q) unexpected err: %v", tc.runtime, tc.name, err)
+		}
+		if got != tc.want {
+			t.Fatalf("verbFor(%q,%q) = %q, want %q", tc.runtime, tc.name, got, tc.want)
+		}
+	}
+	if _, err := verbFor("bogus", "x"); err == nil {
+		t.Fatal("verbFor with an unknown runtime must return an error, not guess a verb")
+	}
+}