1 files changed, 63 insertions, 0 deletions
diff --git a/python/vyos/systemversions.py b/python/vyos/systemversions.py
new file mode 100644
index 000000000..5c4deca29
--- /dev/null
+++ b/python/vyos/systemversions.py
@@ -0,0 +1,63 @@
+# Copyright 2019 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
+import re
+import sys
+import json
+
+import vyos.defaults
+
+def get_system_versions():
+    """
+    Get component versions from running system: read vyatta directory
+    structure for versions, then read vyos JSON file. It is a critical
+    error if either migration directory or JSON file is unreadable.
+    """
+    system_versions = {}
+
+    try:
+        version_info = os.listdir(vyos.defaults.directories['current'])
+    except OSError as err:
+        print("OS error: {}".format(err))
+        sys.exit(1)
+
+    for info in version_info:
+        if re.match(r'[\w,-]+@\d+', info):
+            pair = info.split('@')
+            system_versions[pair[0]] = int(pair[1])
+
+    version_dict = {}
+    path = vyos.defaults.version_file
+
+    if os.path.isfile(path):
+        with open(path, 'r') as f:
+            try:
+                version_dict = json.load(f)
+            except ValueError as err:
+                print(f"\nValue error in {path}: {err}")
+                sys.exit(1)
+
+        for k, v in version_dict.items():
+            if not isinstance(v, int):
+                print(f"\nType error in {path}; expecting Dict[str, int]")
+                sys.exit(1)
+            existing = system_versions.get(k)
+            if existing is None:
+                system_versions[k] = v
+            elif v > existing:
+                system_versions[k] = v
+
+    return system_versions