Add the admin.GetPanic() method.

pkg/admin/cli.go

@@ -612,3 +612,27 @@ func (adm *Admin) ActiveVCL() (VCLData, error) {
 	}
 	return vcl, nil
 }
+
+// GetPanic encapsulates the "panic.show" command. error is non-nil
+// when the response was neither of OK or Cant (Cant is the status
+// when there was no panic to show). In that case, the error is an
+// UnexpectedResponse, which wraps the response from Varnish.
+//
+// When error is nil, the most recent panic string is returned, or the
+// empty string if there has been no panic since Varnish started or
+// since the panic was cleared.
+func (adm *Admin) GetPanic() (string, error) {
+	resp, err := adm.Command("panic.show")
+	if err != nil {
+		return "", err
+	}
+	if resp.Code == Cant {
+		// Don't panic!
+		return "", nil
+	}
+	if resp.Code != OK {
+		badResp := UnexpectedResponse{Response: resp}
+		return "", badResp
+	}
+	return resp.Msg, nil
+}