1 files changed, 113 insertions, 0 deletions
diff --git a/src/helpers/config_dependency.py b/src/helpers/config_dependency.py
new file mode 100644
index 0000000..817bcc6
--- /dev/null
+++ b/src/helpers/config_dependency.py
@@ -0,0 +1,113 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2023 VyOS maintainers and contributors
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 or later as
+# published by the Free Software Foundation.
+#
+# This program 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+#
+
+import os
+import sys
+import json
+from argparse import ArgumentParser
+from argparse import ArgumentTypeError
+from graphlib import TopologicalSorter, CycleError
+
+# addon packages will need to specify the dependency directory
+data_dir = '/usr/share/vyos/'
+dependency_dir = os.path.join(data_dir, 'config-mode-dependencies')
+
+def dict_merge(source, destination):
+    from copy import deepcopy
+    tmp = deepcopy(destination)
+
+    for key, value in source.items():
+        if key not in tmp:
+            tmp[key] = value
+        elif isinstance(source[key], dict):
+            tmp[key] = dict_merge(source[key], tmp[key])
+
+    return tmp
+
+def read_dependency_dict(dependency_dir: str = dependency_dir) -> dict:
+    res = {}
+    for dep_file in os.listdir(dependency_dir):
+        if not dep_file.endswith('.json'):
+            continue
+        path = os.path.join(dependency_dir, dep_file)
+        with open(path) as f:
+            d = json.load(f)
+        if dep_file == 'vyos-1x.json':
+            res = dict_merge(res, d)
+        else:
+            res = dict_merge(d, res)
+
+    return res
+
+def graph_from_dependency_dict(d: dict) -> dict:
+    g = {}
+    for k in list(d):
+        g[k] = set()
+        # add the dependencies for every sub-case; should there be cases
+        # that are mutally exclusive in the future, the graphs will be
+        # distinguished
+        for el in list(d[k]):
+            g[k] |= set(d[k][el])
+
+    return g
+
+def is_acyclic(d: dict) -> bool:
+    g = graph_from_dependency_dict(d)
+    ts = TopologicalSorter(g)
+    try:
+        # get node iterator
+        order = ts.static_order()
+        # try iteration
+        _ = [*order]
+    except CycleError:
+        return False
+
+    return True
+
+def check_dependency_graph(dependency_dir: str = dependency_dir,
+                           supplement: str = None) -> bool:
+    d = read_dependency_dict(dependency_dir=dependency_dir)
+    if supplement is not None:
+        with open(supplement) as f:
+            d = dict_merge(json.load(f), d)
+
+    return is_acyclic(d)
+
+def path_exists(s):
+    if not os.path.exists(s):
+        raise ArgumentTypeError("Must specify a valid vyos-1x dependency directory")
+    return s
+
+def main():
+    parser = ArgumentParser(description='generate and save dict from xml defintions')
+    parser.add_argument('--dependency-dir', type=path_exists,
+                        default=dependency_dir,
+                        help='location of vyos-1x dependency directory')
+    parser.add_argument('--supplement', type=str,
+                        help='supplemental dependency file')
+    args = vars(parser.parse_args())
+
+    if not check_dependency_graph(**args):
+        print("dependency error: cycle exists")
+        sys.exit(1)
+
+    print("dependency graph acyclic")
+    sys.exit(0)
+
+if __name__ == '__main__':
+    main()