From 1230e04c3e196f6cfd614703dbc7ecf8f62ff74b Mon Sep 17 00:00:00 2001
From: Pim van Pelt <pim@ipng.nl>
Date: Sat, 9 Apr 2022 20:12:21 +0000
Subject: [PATCH] Refactor validators into a list, and add a custom validator
 function, which is passed the YAML as an argument, and will return (rv,msgs)
 to signal custom semantic validation results

---
 config/__init__.py | 56 +++++++++++++++++-----------------------------
 tests.py           |  8 +++++++
 2 files changed, 29 insertions(+), 35 deletions(-)

diff --git a/config/__init__.py b/config/__init__.py
index 0b4d894..65808d6 100644
--- a/config/__init__.py
+++ b/config/__init__.py
@@ -69,6 +69,13 @@ class Validator(object):
         self.logger.addHandler(logging.NullHandler())
 
         self.schema = schema
+        self.validators = [
+           validate_bondethernets,
+           validate_interfaces,
+           validate_loopbacks,
+           validate_bridgedomains,
+           validate_vxlan_tunnels,
+           validate_taps ]
 
     def validate(self, yaml):
         ret_rv = True
@@ -107,41 +114,12 @@ class Validator(object):
 
         self.logger.debug("Validating Semantics...")
 
-        rv, msgs = validate_bondethernets(yaml)
-        if msgs:
-            ret_msgs.extend(msgs)
-        if not rv:
-            ret_rv = False
-
-        rv, msgs = validate_interfaces(yaml)
-        if msgs:
-            ret_msgs.extend(msgs)
-        if not rv:
-            ret_rv = False
-
-        rv, msgs = validate_loopbacks(yaml)
-        if msgs:
-            ret_msgs.extend(msgs)
-        if not rv:
-            ret_rv = False
-
-        rv, msgs = validate_bridgedomains(yaml)
-        if msgs:
-            ret_msgs.extend(msgs)
-        if not rv:
-            ret_rv = False
-
-        rv, msgs = validate_vxlan_tunnels(yaml)
-        if msgs:
-            ret_msgs.extend(msgs)
-        if not rv:
-            ret_rv = False
-
-        rv, msgs = validate_taps(yaml)
-        if msgs:
-            ret_msgs.extend(msgs)
-        if not rv:
-            ret_rv = False
+        for v in self.validators:
+            rv, msgs = v(yaml)
+            if msgs:
+                ret_msgs.extend(msgs)
+            if not rv:
+                ret_rv = False
 
         if ret_rv:
             self.logger.debug("Semantics correctly validated")
@@ -162,3 +140,11 @@ class Validator(object):
 
         self.logger.info("Configuration validated successfully")
         return True
+
+    def add_validator(self, func):
+        """ Add a validator function, which strictly takes the prototype
+               rv, msgs = func(yaml)
+            returning a Boolean success value in rv and a List of strings
+            in msgs. The function will be passed the configuration YAML and
+            gets to opine if it's valid or not. """
+        self.validators.append(func)
diff --git a/tests.py b/tests.py
index 215d08e..6b6073b 100755
--- a/tests.py
+++ b/tests.py
@@ -27,6 +27,14 @@ except ImportError:
     print("ERROR: install argparse manually: sudo pip install argparse")
     sys.exit(-2)
 
+def example_validator(yaml):
+    """ A simple example validator that takes the YAML configuration file as an input,
+    and returns a tuple of rv (return value, True is success), and a list of string
+    messages to the validation framework. """
+    rv = True
+    msgs = []
+
+    return rv, msgs
 
 class YAMLTest(unittest.TestCase):
     def __init__(self, testName, yaml_filename, yaml_schema):