Add ip_interface() validator

README.md

@@ -1,17 +1,38 @@
 ## Design
 
-### Validators
+### YAML Configuration
 
-Validators are functions which are passed the fully formed YAML configuration and are meant to
+The main file that is handled by this program is the **Configuration File**.
-check it for syntax and semantic validity. A validator has a unique name and takes the (yaml)
-configuration as the only argument. Validators are expected to return a tuple of (bool,[string])
-where the boolean signals success (False meaning the validator rejected the configuration file,
-True meaning it is known to be correct), and a list of zero or more strings which contain messages
-meant for human consumption. They can contain INFO, WARN or ERROR messages, and are meant to help
-the caller understand why the validator rejected the configuration.
 
-Validators can be disabled with the --skip-validator <name> [<name>] flag. It is not
+## Validation
-advised to skip validators. The purpose of the validators is to ensure the configuration is sane
-and semantically correct.
 
-Validators can be registered as follows:
+There are three types of validation: _schema_ which ensures that the input YAML has the correct
+fields of well known types, _semantic_ which ensures that the configuration doesn't violate
+semantic constraints and _runtime_ which ensures that the configuration can be applied to the
+VPP daemon.
+
+### Schema Validators
+
+First the configuration file is held against a structural validator, provided by [Yamale](https://github.com/23andMe/Yamale/).
+Based on a validation schema in `schema.yaml`, the input file is checked for syntax correctness.
+For example, a `dot1q` field must be an integer between 1 and 4095, wile an `lcp` string must
+match a certain regular expression. After this first pass of syntax validation, I'm certain that
+_if_ a field is set, it is of the right type (ie. string, int, enum). 
+
+### Semantic Validators
+
+A set of semantic validators, each with a unique name, ensure that the _semantics_ of the YAML
+are correct. For example, a physical interface cannot have an LCP, addresses or sub-interfaces,
+if it is to be a member of a BondEthernet.
+
+Validators are expected to return a tuple of (bool,[string]) where the boolean signals success
+(False meaning the validator rejected the configuration file, True meaning it is known to be
+correct), and a list of zero or more strings which contain messages meant for human consumption.
+
+### Runtime Validators
+
+After the configuration file is considered syntax and semanticly valid, there is one more set of
+checks to perform -- runtime validators ensure that the configuration elements such as physical
+network devices (ie. `HundredGigabitEthernet12/0/0` or plugin `lcpng` are present on the system.
+It does this by connecting to VPP and querying the runtime state to ensure that what is modeled
+in the configuration file is able to be committed.

schema.yaml

@@ -9,17 +9,13 @@ interface:
   description: str(exclude='\'"',required=False)
   lcp: str(max=8,matches='[a-z]+[a-z0-9-]{,7}',required=False)
   mac: mac(required=False)
-  addresses: list(include('v4'),include('v6'),min=1,max=6,required=False)
+  addresses: list(ip_interface(),min=1,max=6,required=False)
   sub-interfaces: map(include('sub-interface'),key=int(min=1,max=4294967295),required=False)
 ---
-v4: str(matches='[0-9\.]+/[0-9]+')
----
-v6: str(matches='[0-9a-f:]+/[0-9]+',ignore_case=True)
----
 sub-interface:
   description: str(exclude='\'"',required=False)
   lcp: str(max=8,matches='[a-z]+[a-z0-9-]{,7}',required=False)
-  addresses: list(ip(),required=False)
+  addresses: list(ip_interface(),required=False)
   encapsulation: include('encapsulation',required=False)
 ---
 encapsulation:

validator/__init__.py

@@ -17,6 +17,33 @@ from validator.bondethernet import bondethernet
 from validator.interface import interface
 from validator.bridgedomain import bridgedomain
 
+from yamale.validators import DefaultValidators, Validator
+import ipaddress
+
+class IPInterfaceWithPrefixLength(Validator):
+    """ Custom IPAddress validator - takes IP/prefixlen as input:
+        192.0.2.1/29 or 2001:db8::1/64 are correct. The PrefixLength
+        is required, and must be a number (0-32 for IPv4 and 0-128 for
+        IPv6).
+    """
+    tag = 'ip_interface'
+
+    def _is_valid(self, value):
+        try:
+            network = ipaddress.ip_interface(value)
+        except:
+            return False
+        if not '/' in value:
+            return False
+        e = value.split('/')
+        if not len(e) == 2:
+            return False
+        if not e[1].isnumeric():
+            return False
+        return True
+
+
+
 class NullHandler(logging.Handler):
     def emit(self, record):
         pass
@@ -35,7 +62,9 @@ class Validator(object):
         if self.args.schema:
             try:
                 self.logger.info("Validating against schema %s" % self.args.schema)
-                schema = yamale.make_schema(self.args.schema)
+                validators = DefaultValidators.copy()
+                validators[IPInterfaceWithPrefixLength.tag] = IPInterfaceWithPrefixLength
+                schema = yamale.make_schema(self.args.schema, validators=validators)
                 data = yamale.make_data(content=str(yaml))
                 yamale.validate(schema, data)
                 self.logger.debug("Schema correctly validated by yamale")