move filters to single file, fix imports

src/netom/__init__.py

@@ -9,7 +9,6 @@
 
 from . import filters
 from .exception import NetomValidationError
-from .j2_filters import address_to_mask, address_to_wildcard, line_to_mask, line_to_wildcard
 
 # TODO move out of this namespace
 from .models import BgpNeighbor
@@ -43,12 +42,12 @@ def __init__(self, model_version, model_type, search_path=None):
 
     def set_search_path(self, search_path):
         self.engine = tmpl.get_engine("jinja2")(search_path=search_path)
-        self.engine.engine.filters["make_variable_name"] = make_variable_name
-        self.engine.engine.filters["ip_version"] = ip_version
-        self.engine.engine.filters["address_to_mask"] = address_to_mask
-        self.engine.engine.filters["address_to_wildcard"] = address_to_wildcard
-        self.engine.engine.filters["line_to_mask"] = line_to_mask
-        self.engine.engine.filters["line_to_wildcard"] = line_to_wildcard
+        self.engine.engine.filters["make_variable_name"] = filters.make_variable_name
+        self.engine.engine.filters["ip_version"] = filters.ip_version
+        self.engine.engine.filters["address_to_mask"] = filters.address_to_mask
+        self.engine.engine.filters["address_to_wildcard"] = filters.address_to_wildcard
+        self.engine.engine.filters["line_to_mask"] = filters.line_to_mask
+        self.engine.engine.filters["line_to_wildcard"] = filters.line_to_wildcard
         # self.engine.search_path = os.path.dirname(search_path)
 
         for name in filters.__all__:

src/netom/filters.py

@@ -1,4 +1,10 @@
 import ipaddress
+import re
+from ipaddress import IPv4Address
+from jinja2 import pass_context
+
+
+r_ip_nn = re.compile("[\d.]{7,15}/\d{1,2}")
 
 __all__ = [
     "make_variable_name",
@@ -8,8 +14,6 @@
     "ip_version",
 ]
 
-from jinja2 import pass_context
-
 
 @pass_context
 def render_template(context, value):
@@ -60,3 +64,42 @@ def ip_version(value):
     Returns version of passed IP address.
     """
     return ipaddress.ip_interface(value).version
+
+
+def address_to_mask(addr):
+    """
+    Transform A.B.C.D/nn into A.B.C.D M.M.M.M subnet mask format.
+    """
+    ipaddr4 = ipaddress.ip_interface(addr)
+    return f"{ipaddr4.ip} {ipaddr4.netmask}"
+
+
+def address_to_wildcard(addr):
+    """
+    Transform A.B.C.D/nn into A.B.C.D W.W.W.W subnet wildcard format.
+
+    credit for the mask shenanigans to George Shuklin
+    https://medium.com/opsops/wildcard-masks-operations-in-python-16acf1c35683
+    """
+    ipnet4 = ipaddress.ip_network(addr)
+    wildcard = str(IPv4Address(int(IPv4Address(ipnet4.netmask))^(2**32-1)))
+    return f"{ipnet4.network_address} {wildcard}"
+
+
+def line_to_mask(line):
+    """
+    Search for any IPv4/nn tokens in the `line` argument and transform them into mask format.
+    E.g. `permit ip 10.0.0.0/8` any -> `permit ip 10.0.0.0 255.0.0.0 any`
+    """
+    tokens = line.split()
+    return " ".join([address_to_mask(token) if r_ip_nn.match(token) else token for token in tokens])
+
+
+def line_to_wildcard(line):
+    """
+    Search for any IPv4/nn tokens in the `line` argument and transform them into wildcard format.
+    E.g. `permit ip 10.0.0.0/8` any -> `permit ip 10.0.0.0 0.255.255.255 any`
+    """
+    tokens = line.split()
+    return " ".join([address_to_wildcard(token) if r_ip_nn.match(token) else token for token in tokens])
+

tests/test_j2_filters.py → tests/test_filters.py

@@ -1,5 +1,5 @@
 
-from netom.j2_filters import address_to_mask, address_to_wildcard, line_to_mask, line_to_wildcard
+from netom.filters import address_to_mask, address_to_wildcard, line_to_mask, line_to_wildcard
 import pytest