config: T5443: add config merge_defaults method

Drop low-level merge_defaults function in favor of Config method for
a middle-grained level of control when merging defaults.

3 files changed, 110 insertions, 100 deletions

diff --git a/python/vyos/config.py b/python/vyos/config.py
index 179f60c43..6fececd76 100644
--- a/python/vyos/config.py
+++ b/python/vyos/config.py
@@ -66,17 +66,31 @@ In operational mode, all functions return values from the running config.
 import re
 import json
 from copy import deepcopy
+from typing import Union
 
 import vyos.configtree
-from vyos.xml_ref import multi_to_list, from_source
-from vyos.xml_ref import merge_defaults, relative_defaults
-from vyos.utils.dict import get_sub_dict, mangle_dict_keys
-from vyos.configsource import ConfigSource, ConfigSourceSession
+from vyos.xml_ref import multi_to_list
+from vyos.xml_ref import from_source
+from vyos.xml_ref import ext_dict_merge
+from vyos.xml_ref import relative_defaults
+from vyos.utils.dict import get_sub_dict
+from vyos.utils.dict import mangle_dict_keys
+from vyos.configsource import ConfigSource
+from vyos.configsource import ConfigSourceSession
 
 class ConfigDict(dict):
     _from_defaults = {}
-    def from_defaults(self, path: list[str]):
+    _dict_kwargs = {}
+    def from_defaults(self, path: list[str]) -> bool:
         return from_source(self._from_defaults, path)
+    @property
+    def kwargs(self) -> dict:
+        return self._dict_kwargs
+
+def config_dict_merge(src: dict, dest: Union[dict, ConfigDict]) -> ConfigDict:
+    if not isinstance(dest, ConfigDict):
+        dest = ConfigDict(dest)
+    return ext_dict_merge(src, dest)
 
 class Config(object):
     """
@@ -229,6 +243,13 @@ class Config(object):
 
         return config_dict
 
+    def verify_mangling(self, key_mangling):
+        if not (isinstance(key_mangling, tuple) and \
+                (len(key_mangling) == 2) and \
+                isinstance(key_mangling[0], str) and \
+                isinstance(key_mangling[1], str)):
+            raise ValueError("key_mangling must be a tuple of two strings")
+
     def get_config_dict(self, path=[], effective=False, key_mangling=None,
                         get_first_key=False, no_multi_convert=False,
                         no_tag_node_value_mangle=False,
@@ -243,44 +264,37 @@ class Config(object):
 
         Returns: a dict representation of the config under path
         """
+        kwargs = locals().copy()
+        del kwargs['self']
+        del kwargs['no_multi_convert']
+        del kwargs['with_defaults']
+        del kwargs['with_recursive_defaults']
+
         lpath = self._make_path(path)
         root_dict = self.get_cached_root_dict(effective)
         conf_dict = get_sub_dict(root_dict, lpath, get_first_key=get_first_key)
 
-        if key_mangling is None and no_multi_convert and not (with_defaults or with_recursive_defaults):
-            return deepcopy(conf_dict)
-
         rpath = lpath if get_first_key else lpath[:-1]
 
         if not no_multi_convert:
             conf_dict = multi_to_list(rpath, conf_dict)
 
+        if key_mangling is not None:
+            self.verify_mangling(key_mangling)
+            conf_dict = mangle_dict_keys(conf_dict,
+                                         key_mangling[0], key_mangling[1],
+                                         abs_path=rpath,
+                                         no_tag_node_value_mangle=no_tag_node_value_mangle)
+
         if with_defaults or with_recursive_defaults:
+            defaults = self.get_config_defaults(**kwargs,
+                                                recursive=with_recursive_defaults)
+            conf_dict = config_dict_merge(defaults, conf_dict)
+        else:
             conf_dict = ConfigDict(conf_dict)
-            conf_dict = merge_defaults(lpath, conf_dict,
-                                       get_first_key=get_first_key,
-                                       recursive=with_recursive_defaults)
 
-        if key_mangling is None:
-            return conf_dict
-
-        if not (isinstance(key_mangling, tuple) and \
-                (len(key_mangling) == 2) and \
-                isinstance(key_mangling[0], str) and \
-                isinstance(key_mangling[1], str)):
-            raise ValueError("key_mangling must be a tuple of two strings")
-
-        def mangle(obj):
-            return mangle_dict_keys(obj, key_mangling[0], key_mangling[1],
-                                    abs_path=rpath,
-                                    no_tag_node_value_mangle=no_tag_node_value_mangle)
-
-        if isinstance(conf_dict, ConfigDict):
-            from_defaults = mangle(conf_dict._from_defaults)
-            conf_dict = mangle(conf_dict)
-            conf_dict._from_defaults = from_defaults
-        else:
-            conf_dict = mangle(conf_dict)
+        # save optional args for a call to get_config_defaults
+        setattr(conf_dict, '_dict_kwargs', kwargs)
 
         return conf_dict
 
@@ -294,21 +308,29 @@ class Config(object):
         defaults = relative_defaults(lpath, conf_dict,
                                      get_first_key=get_first_key,
                                      recursive=recursive)
-        if key_mangling is None:
-            return defaults
 
         rpath = lpath if get_first_key else lpath[:-1]
 
-        if not (isinstance(key_mangling, tuple) and \
-                (len(key_mangling) == 2) and \
-                isinstance(key_mangling[0], str) and \
-                isinstance(key_mangling[1], str)):
-            raise ValueError("key_mangling must be a tuple of two strings")
-
-        defaults = mangle_dict_keys(defaults, key_mangling[0], key_mangling[1], abs_path=rpath, no_tag_node_value_mangle=no_tag_node_value_mangle)
+        if key_mangling is not None:
+            self.verify_mangling(key_mangling)
+            defaults = mangle_dict_keys(defaults,
+                                        key_mangling[0], key_mangling[1],
+                                        abs_path=rpath,
+                                        no_tag_node_value_mangle=no_tag_node_value_mangle)
 
         return defaults
 
+    def merge_defaults(self, config_dict: ConfigDict, recursive=False):
+        if not isinstance(config_dict, ConfigDict):
+            raise TypeError('argument is not of type ConfigDict')
+        if not config_dict.kwargs:
+            raise ValueError('argument missing metadata')
+
+        args = config_dict.kwargs
+        d = self.get_config_defaults(**args, recursive=recursive)
+        config_dict = config_dict_merge(d, config_dict)
+        return config_dict
+
     def is_multi(self, path):
         """
         Args:
diff --git a/python/vyos/xml_ref/__init__.py b/python/vyos/xml_ref/__init__.py
index 9f7a31e2c..02bbaffd8 100644
--- a/python/vyos/xml_ref/__init__.py
+++ b/python/vyos/xml_ref/__init__.py
@@ -13,9 +13,12 @@
 # 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/>.
 
-from typing import Optional, Union
+from typing import Optional, Union, TYPE_CHECKING
 from vyos.xml_ref import definition
 
+if TYPE_CHECKING:
+    from vyos.config import ConfigDict
+
 def load_reference(cache=[]):
     if cache:
         return cache[0]
@@ -49,9 +52,6 @@ def is_leaf(path: list) -> bool:
 def cli_defined(path: list, node: str, non_local=False) -> bool:
     return load_reference().cli_defined(path, node, non_local=non_local)
 
-def from_source(d: dict, path: list) -> bool:
-    return load_reference().from_source(d, path)
-
 def component_version() -> dict:
     return load_reference().component_version()
 
@@ -72,8 +72,8 @@ def relative_defaults(rpath: list, conf: dict, get_first_key=False,
                                               get_first_key=get_first_key,
                                               recursive=recursive)
 
-def merge_defaults(path: list, conf: dict, get_first_key=False,
-                   recursive=False) -> dict:
-    return load_reference().merge_defaults(path, conf,
-                                           get_first_key=get_first_key,
-                                           recursive=recursive)
+def from_source(d: dict, path: list) -> bool:
+    return definition.from_source(d, path)
+
+def ext_dict_merge(source: dict, destination: Union[dict, 'ConfigDict']):
+    return definition.ext_dict_merge(source, destination)
diff --git a/python/vyos/xml_ref/definition.py b/python/vyos/xml_ref/definition.py
index b0b8a2605..38e07f0a7 100644
--- a/python/vyos/xml_ref/definition.py
+++ b/python/vyos/xml_ref/definition.py
@@ -20,6 +20,45 @@ from typing import Optional, Union, Any, TYPE_CHECKING
 if TYPE_CHECKING:
     from vyos.config import ConfigDict
 
+def set_source_recursive(o: Union[dict, str, list], b: bool):
+    d = {}
+    if not isinstance(o, dict):
+        d = {'_source': b}
+    else:
+        for k, v in o.items():
+            d[k] = set_source_recursive(v, b)
+        d |= {'_source': b}
+    return d
+
+def source_dict_merge(src: dict, dest: dict):
+    from copy import deepcopy
+    dst = deepcopy(dest)
+    from_src = {}
+
+    for key, value in src.items():
+        if key not in dst:
+            dst[key] = value
+            from_src[key] = set_source_recursive(value, True)
+        elif isinstance(src[key], dict):
+            dst[key], f = source_dict_merge(src[key], dst[key])
+            f |= {'_source': False}
+            from_src[key] = f
+
+    return dst, from_src
+
+def ext_dict_merge(src: dict, dest: Union[dict, 'ConfigDict']):
+    d, f = source_dict_merge(src, dest)
+    if hasattr(d, '_from_defaults'):
+        setattr(d, '_from_defaults', f)
+    return d
+
+def from_source(d: dict, path: list) -> bool:
+    for key in path:
+        d  = d[key] if key in d else {}
+        if not d or not isinstance(d, dict):
+            return False
+    return d.get('_source', False)
+
 class Xml:
     def __init__(self):
         self.ref = {}
@@ -221,43 +260,6 @@ class Xml:
             return False
         return True
 
-    def _set_source_recursive(self, o: Union[dict, str, list], b: bool):
-        d = {}
-        if not isinstance(o, dict):
-            d = {'_source': b}
-        else:
-            for k, v in o.items():
-                d[k] = self._set_source_recursive(v, b)
-            d |= {'_source': b}
-        return d
-
-    # use local copy of function in module configdict, to avoid circular
-    # import
-    #
-    # extend dict_merge to keep track of keys only in source
-    def _dict_merge(self, source, destination):
-        from copy import deepcopy
-        dest = deepcopy(destination)
-        from_source = {}
-
-        for key, value in source.items():
-            if key not in dest:
-                dest[key] = value
-                from_source[key] = self._set_source_recursive(value, True)
-            elif isinstance(source[key], dict):
-                dest[key], f = self._dict_merge(source[key], dest[key])
-                f |= {'_source': False}
-                from_source[key] = f
-
-        return dest, from_source
-
-    def from_source(self, d: dict, path: list) -> bool:
-        for key in path:
-            d  = d[key] if key in d else {}
-            if not d or not isinstance(d, dict):
-                return False
-        return d.get('_source', False)
-
     def _relative_defaults(self, rpath: list, conf: dict, recursive=False) -> dict:
         res: dict = {}
         res = self.get_defaults(rpath, recursive=recursive,
@@ -298,17 +300,3 @@ class Xml:
                 res = {}
 
         return res
-
-    def merge_defaults(self, path: list, conf: Union[dict, 'ConfigDict'],
-                       get_first_key=False, recursive=False) -> dict:
-        """Return config dict with defaults non-destructively merged
-
-        This merges non-recursive defaults relative to the config dict.
-        """
-        d = self.relative_defaults(path, conf, get_first_key=get_first_key,
-                                   recursive=recursive)
-        d, f = self._dict_merge(d, conf)
-        d = type(conf)(d)
-        if hasattr(d, '_from_defaults'):
-            setattr(d, '_from_defaults', f)
-        return d