Module management system: Initial impl finished

2 files changed, 117 insertions, 20 deletions

diff --git a/doc/roadmap.rst b/doc/roadmap.rst
index 0a752ed..19a1b2f 100644
--- a/doc/roadmap.rst
+++ b/doc/roadmap.rst
@@ -6,7 +6,7 @@
 1.0 (2020 Q3)
 =============
 
-[/] Module management system
+[X] Module management system
 ----------------------------
 
 * [X] Track name/revision/namespace, and register with NSMAP
@@ -14,9 +14,9 @@
   * Namespace includes prefix, since this is standardised.  i.e.
     ns "urn:ietf:params:xml:ns:yang:ietf-interfaces" -> prefix "if:".
 
-* [ ] Track features implemented
+* [X] Track features implemented
 
-* [ ] Handle import-only modules
+* [X] Handle import-only modules
 
 * [ ] Submodule support?  (possibly post-1.0)
 
diff --git a/ncserver/base/modman.py b/ncserver/base/modman.py
index 551c1cd..1423be1 100644
--- a/ncserver/base/modman.py
+++ b/ncserver/base/modman.py
@@ -24,6 +24,75 @@ MODULE_SET_CHANGE_SIGNAL = Signal(('base/ModuleManager', 'module_set_changed'))
 yang-library-change notification should be fired, when this is supported."""
 
 
+def _import_compatible(existing, improps):
+    """Determine if an imported module is compatible with the existing
+    module that has the same name/revision.
+
+    :param existing:
+    The dictionary of properties for the existing module.
+
+    :param improps:
+    The dictionary of properties for the candidate module.
+
+    :returns bool:
+    True if compatible, False otherwise.
+    """
+    return (improps.keys() == existing.keys() and
+            all([existing[key] == improps[key] for key in existing.keys()]))
+
+
+def _gen_modnode(parent, module):
+    """Generate a yanglib:module node.
+
+    The generated node is in the NMDA format.  With some massaging, it
+    could be used for the deprecated non-NMDA format.
+
+    :param parent:
+    The parent XML node.
+
+    :param module:
+    The module.
+
+    :returns:
+    The generated module node.
+    """
+    modnode = util.subelm(parent, 'yanglib:module')
+    modnode.append(util.leaf_elm('yanglib:name', module.M_NAME))
+    modnode.append(util.leaf_elm('yanglib:revision', module.M_REVISION))
+    modnode.append(util.leaf_elm('yanglib:namespace', module.M_NS))
+    if getattr(module, 'M_FEATURES', None) is not None:
+        for feature in module.M_FEATURES:
+            modnode.append(util.leaf_elm('yanglib:feature', feature))
+    return modnode
+
+
+def _gen_modnode_import(parent, nodename, imname, improps):
+    """Generate a node for an import-only module.
+
+    :param parent:
+    The parent XML node.
+
+    :param nodename:
+    The name of the XML node to create.  For NMDA library contents, use
+    'yanglib:import-only-module'; otherwise, use 'yanglib:module'.
+
+    :param imname:
+    The name of the imported module in M_IMPORTS syntax.
+
+    :param improps:
+    The M_IMPORTS property dictionary for this imported module.
+
+    :returns:
+    The generated module node.
+    """
+    imn_name, imn_rev = imname.split('@')
+    modnode = util.subelm(parent, nodename)
+    modnode.append(util.leaf_elm('yanglib:name', imn_name))
+    modnode.append(util.leaf_elm('yanglib:revision', imn_rev))
+    modnode.append(util.leaf_elm('yanglib:namespace', improps['ns']))
+    return modnode
+
+
 class ModuleManager:
     """Manages the modules for the NETCONF for APK Distributions server.
 
@@ -39,9 +108,16 @@ class ModuleManager:
     M_NS = "urn:ietf:params:xml:ns:yang:ietf-yang-library"
     M_NAME = "ietf-yang-library"
     M_REVISION = "2019-01-04"
+    M_IMPORTS = {'ietf-yang-types@2013-07-15':
+                 {'ns': "urn:ietf:params:xml:ns:yang:ietf-yang-types",
+                  'prefix': "yang"},
+                 'ietf-inet-types@2013-07-16':
+                 {'ns': "urn:ietf:params:xml:ns:yang:ietf-inet-types",
+                  'prefix': "inet"}}
 
     def __init__(self):
         self.modules = {'ncserver.base.modman': self}
+        self.imports = dict(self.M_IMPORTS)
         self.library = {'ncserver.base.modman':
                         '{}@{}'.format(self.M_NAME, self.M_REVISION)}
         nsmap_add(self.M_PREFIX, self.M_NS)
@@ -80,34 +156,47 @@ class ModuleManager:
                               mod.M_ABI_VERSION)
             return None
 
+        if getattr(mod, 'M_IMPORTS', None) is not None:
+            for imname, improps in mod.M_IMPORTS:
+                if imname in self.imports:
+                    if not _import_compatible(self.imports[imname], improps):
+                        self.logger.error(_("Module '%s' has incompatible "
+                                            "imported module '%s'"), name,
+                                          imname)
+                        return None
+                else:
+                    self.imports[imname] = improps
+
         self.logger.info(_("Loading module '%s' with ABI %d for namespace %s"),
                          name, mod.M_ABI_VERSION, mod.M_NS)
 
         self.modules[name] = mod
         self.library[name] = '{}@{}'.format(mod.M_NAME, mod.M_REVISION)
         nsmap_add(mod.M_PREFIX, mod.M_NS)
+        MODULE_SET_CHANGE_SIGNAL.call(name, mod)
         return name
 
     def running(self, node):
         """Return running configuration information."""
         # ietf-yang-library is state-only.
 
-    def operational(self, node):
-        """Return configuration and device state information."""
-        module_set_id = hashlib.sha256(','.join(self.modules.keys()).encode())
-        content_id = module_set_id.hexdigest()
+    def _gen_yang_library(self, node, content_id):
+        """Generate yanglib:yang-library node.
 
-        # NDMA-enabled yang-library node.
+        :param node:
+        The XML node to append to.
+
+        :param content_id:
+        The unique Content ID for this library.
+        """
         lib = util.subelm(node, 'yanglib:yang-library')
         modset = util.subelm(lib, 'yanglib:module-set')
         modset.append(util.leaf_elm('yanglib:name', 'netconfapk'))
         for module in self.modules.values():
-            # XXX or import-only-module, if it's import-only
-            modnode = util.subelm(modset, 'yanglib:module')
-            modnode.append(util.leaf_elm('yanglib:name', module.M_NAME))
-            modnode.append(util.leaf_elm('yanglib:revision',
-                                         module.M_REVISION))
-            modnode.append(util.leaf_elm('yanglib:namespace', module.M_NS))
+            _gen_modnode(modset, module)
+        for imname, improps in self.imports.items():
+            _gen_modnode_import(modset, 'yanglib:import-only-module', imname,
+                                improps)
         schema = util.subelm(lib, 'yanglib:schema')
         schema.append(util.leaf_elm('yanglib:name', 'apkschema'))
         schema.append(util.leaf_elm('yanglib:module-set', 'netconfapk'))
@@ -118,19 +207,27 @@ class ModuleManager:
             dsnode.append(util.leaf_elm('schema', 'apkschema'))
 
         lib.append(util.leaf_elm('yanglib:content-id', content_id))
+        return lib
+
+    def operational(self, node):
+        """Return configuration and device state information."""
+        module_set_id = hashlib.sha256(','.join(self.modules.keys()).encode())
+        content_id = module_set_id.hexdigest()
+
+        # NDMA-enabled yang-library node.
+        self._gen_yang_library(node, content_id)
 
         # Deprecated modules-state node.
         modstate = util.subelm(node, 'yanglib:modules-state')
         modstate.append(util.leaf_elm('yanglib:module-set-id', content_id))
         for module in self.modules.values():
-            modnode = util.subelm(modstate, 'yanglib:module')
-            modnode.append(util.leaf_elm('yanglib:name', module.M_NAME))
-            modnode.append(util.leaf_elm('yanglib:revision',
-                                         module.M_REVISION))
-            modnode.append(util.leaf_elm('yanglib:namespace', module.M_NS))
-            # XXX import-only module support: use 'import'
+            modnode = _gen_modnode(modstate, module)
             modnode.append(util.leaf_elm('yanglib:conformance-type',
                                          'implement'))
+        for imname, improps in self.imports.items():
+            modnode = _gen_modnode_import(modstate, 'yanglib:module', imname,
+                                          improps)
+            modnode.append(util.leaf_elm('yanglib:conformance-type', 'import'))
 
     def collect_running(self, node):
         """Collect all available information for the <running> datastore."""