1 files changed, 95 insertions, 0 deletions
diff --git a/python/vyos/configdep.py b/python/vyos/configdep.py
new file mode 100644
index 000000000..d4b2cc78f
--- /dev/null
+++ b/python/vyos/configdep.py
@@ -0,0 +1,95 @@
+# Copyright 2022 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 json
+import typing
+from inspect import stack
+
+from vyos.util import load_as_module
+from vyos.defaults import directories
+from vyos.configsource import VyOSError
+from vyos import ConfigError
+
+# https://peps.python.org/pep-0484/#forward-references
+# for type 'Config'
+if typing.TYPE_CHECKING:
+    from vyos.config import Config
+
+dependent_func: dict[str, list[typing.Callable]] = {}
+
+def canon_name(name: str) -> str:
+    return os.path.splitext(name)[0].replace('-', '_')
+
+def canon_name_of_path(path: str) -> str:
+    script = os.path.basename(path)
+    return canon_name(script)
+
+def caller_name() -> str:
+    return stack()[-1].filename
+
+def read_dependency_dict() -> dict:
+    path = os.path.join(directories['data'],
+                        'config-mode-dependencies.json')
+    with open(path) as f:
+        d = json.load(f)
+    return d
+
+def get_dependency_dict(config: 'Config') -> dict:
+    if hasattr(config, 'cached_dependency_dict'):
+        d = getattr(config, 'cached_dependency_dict')
+    else:
+        d = read_dependency_dict()
+        setattr(config, 'cached_dependency_dict', d)
+    return d
+
+def run_config_mode_script(script: str, config: 'Config'):
+    path = os.path.join(directories['conf_mode'], script)
+    name = canon_name(script)
+    mod = load_as_module(name, path)
+
+    config.set_level([])
+    try:
+        c = mod.get_config(config)
+        mod.verify(c)
+        mod.generate(c)
+        mod.apply(c)
+    except (VyOSError, ConfigError) as e:
+        raise ConfigError(repr(e))
+
+def def_closure(target: str, config: 'Config',
+                tagnode: typing.Optional[str] = None) -> typing.Callable:
+    script = target + '.py'
+    def func_impl():
+        if tagnode:
+            os.environ['VYOS_TAGNODE_VALUE'] = tagnode
+        run_config_mode_script(script, config)
+    return func_impl
+
+def set_dependents(case: str, config: 'Config',
+                   tagnode: typing.Optional[str] = None):
+    d = get_dependency_dict(config)
+    k = canon_name_of_path(caller_name())
+    l = dependent_func.setdefault(k, [])
+    for target in d[k][case]:
+        func = def_closure(target, config, tagnode)
+        l.append(func)
+
+def call_dependents():
+    k = canon_name_of_path(caller_name())
+    l = dependent_func.get(k, [])
+    while l:
+        f = l.pop(0)
+        f()