Add proper capabilities output

This includes support for tracking features in modules via optional
M_FEATURES list.

1 files changed, 41 insertions, 10 deletions

diff --git a/ncserver/base/modman.py b/ncserver/base/modman.py
index 2c24788..a3b8aad 100644
--- a/ncserver/base/modman.py
+++ b/ncserver/base/modman.py
@@ -176,18 +176,51 @@ class ModuleManager:
         MODULE_SET_CHANGE_SIGNAL.call(name, mod)
         return name
 
+    def capabilities(self) -> list:
+        """Determine the NETCONF capabilities for this server."""
+        capabs = []
+
+        def _cap_for_module(module):
+            base = '{ns}?module={mod}&revision={rev}'.format(
+                    ns=module.M_NS, mod=module.M_NAME, rev=module.M_REVISION
+            )
+            if getattr(module, 'M_FEATURES', None) is not None:
+                return '{base}&features={feat}'.format(
+                        base=base, feat=','.join(module.M_FEATURES)
+                )
+            return base
+
+        def _cap_for_import(imname, improp):
+            name, rev = imname.split('@')
+            return '{ns}?module={mod}&revision={rev}'.format(
+                    ns=improp['ns'], mod=name, rev=rev
+            )
+
+        for imdata in self.imports.items():
+            capabs.append(_cap_for_import(*imdata))
+        for module in self.modules.values():
+            capabs.append(_cap_for_module(module))
+        capabs.append('{ns}?revision={rev}&module-set-id={id}'.format(
+                ns='urn:ietf:params:netconf:capability:yang-library:1.0',
+                rev='2019-01-04', id=self._module_set_id()
+        ))
+
+        return capabs
+
     def running(self, node):
         """Return running configuration information."""
         # ietf-yang-library is state-only.
 
-    def _gen_yang_library(self, node, content_id):
+    def _module_set_id(self):
+        """Retrieve the module set ID for this server."""
+        module_set_id = hashlib.sha256(','.join(self.modules.keys()).encode())
+        return module_set_id.hexdigest()
+
+    def _gen_yang_library(self, node):
         """Generate yanglib: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')
@@ -206,20 +239,18 @@ class ModuleManager:
             dsnode.append(util.leaf_elm('name', store))
             dsnode.append(util.leaf_elm('schema', 'apkschema'))
 
-        lib.append(util.leaf_elm('yanglib:content-id', content_id))
+        lib.append(util.leaf_elm('yanglib:content-id', self._module_set_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)
+        self._gen_yang_library(node)
 
         # Deprecated modules-state node.
         modstate = util.subelm(node, 'yanglib:modules-state')
-        modstate.append(util.leaf_elm('yanglib:module-set-id', content_id))
+        modstate.append(util.leaf_elm('yanglib:module-set-id',
+                        self._module_set_id()))
         for module in self.modules.values():
             modnode = _gen_modnode(modstate, module)
             modnode.append(util.leaf_elm('yanglib:conformance-type',