utils: T5239: add low-level read from config.boot

(cherry picked from commit 56d3f75de487c1dcfd075cf7b65cb16b6501d0ca)

1 files changed, 34 insertions, 0 deletions

diff --git a/python/vyos/utils/config.py b/python/vyos/utils/config.py
new file mode 100644
index 000000000..bd363ce46
--- /dev/null
+++ b/python/vyos/utils/config.py
@@ -0,0 +1,34 @@
+# Copyright 2023 VyOS maintainers and contributors <maintainers@vyos.io>
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+from vyos.defaults import directories
+
+config_file = os.path.join(directories['config'], 'config.boot')
+
+def read_saved_value(path: list):
+    if not isinstance(path, list) or not path:
+        return ''
+    from vyos.configtree import ConfigTree
+    try:
+        with open(config_file) as f:
+            config_string = f.read()
+        ct = ConfigTree(config_string)
+    except Exception:
+        return ''
+    if not ct.exists(path):
+        return ''
+    res = ct.return_values(path)
+    return res[0] if len(res) == 1 else res