frr bgp conf template handling switch_type == voq (#24158)

when switch_type is voq, it could either be a single asic or multi-asic
or even a voq_chassis
bgpd.main.conf.j2 needs to handle the single asic case differently than
the multi-asic or voq_chassis.
A new filter file_exists is now used within j2 files to look for
chasssisdb.conf and determine if its a voq_chassis
Incase of unit test, the test just runs with a json file only. Hence
using a chassisdb_conf_present in it to represent the chassis case

When assigning the loopback0 address, handle the single asic voq case.

Author: saravanan-nexthop

dockers/docker-fpm-frr/frr/bgpd/bgpd.main.conf.j2

@@ -42,7 +42,11 @@ ipv6 prefix-list LOCAL_VLAN_IPV6_PREFIX seq {{ loop.index * 5 }} permit {{ prefi
 {% if DEVICE_METADATA['localhost']['sub_role'] == 'FrontEnd' or DEVICE_METADATA['localhost']['sub_role'] == 'BackEnd' %}
 {% set multi_asic = True %}
 {% endif %}
-{% if multi_asic is defined or DEVICE_METADATA['localhost']['switch_type'] == 'voq' or DEVICE_METADATA['localhost']['switch_type'] == 'chassis-packet' %}
+{% if DEVICE_METADATA['localhost']['switch_type'] == 'voq' and ('chassisdb_conf_present' in DEVICE_METADATA['localhost'] or
+      '/usr/share/sonic/platform/chassisdb.conf' | file_exists) %}
+{% set voq_chassis = True %}
+{% endif %}
+{% if multi_asic is defined or voq_chassis is defined or DEVICE_METADATA['localhost']['switch_type'] == 'chassis-packet' %}
 ip prefix-list V4_P2P_IP permit 0.0.0.0/0 ge 31 le 31
 !
 ipv6 prefix-list V6_P2P_IP permit ::/0 ge 126 le 126
@@ -104,7 +108,7 @@ router bgp {{ DEVICE_METADATA['localhost']['bgp_asn'] }}
 !
 {% endif %}
 {# set router-id #}
-{% if DEVICE_METADATA['localhost']['sub_role'] == 'BackEnd' or DEVICE_METADATA['localhost']['switch_type'] == 'voq' or DEVICE_METADATA['localhost']['switch_type'] == 'chassis-packet' %}
+{% if DEVICE_METADATA['localhost']['sub_role'] == 'BackEnd' or voq_chassis is defined or DEVICE_METADATA['localhost']['switch_type'] == 'chassis-packet' %}
 {% if 'bgp_router_id' in DEVICE_METADATA['localhost'] %}
   bgp router-id {{ DEVICE_METADATA["localhost"]["bgp_router_id"] }}
 {% elif lo4096_ipv4 is not none %}
@@ -122,7 +126,7 @@ router bgp {{ DEVICE_METADATA['localhost']['bgp_asn'] }}
 {% if lo0_ipv4 is not none %}
   network {{ lo0_ipv4 }}/32
 {% endif %}
-{% if lo4096_ipv4 is not none and ((multi_asic is defined and DEVICE_METADATA['localhost']['switch_type'] != 'chassis-packet') or (DEVICE_METADATA['localhost']['switch_type'] == 'voq')) %}
+{% if lo4096_ipv4 is not none and ((multi_asic is defined and DEVICE_METADATA['localhost']['switch_type'] != 'chassis-packet') or (voq_chassis is defined)) %}
   network {{ lo4096_ipv4 }}/32 route-map HIDE_INTERNAL
 {% endif %}
 !
@@ -133,13 +137,13 @@ router bgp {{ DEVICE_METADATA['localhost']['bgp_asn'] }}
     network {{ get_ipv6_loopback_address(LOOPBACK_INTERFACE, "Loopback0") | ip }}/128
 {% else %}
     network {{ get_ipv6_loopback_address(LOOPBACK_INTERFACE, "Loopback0") | ip }}/64
-{% if DEVICE_METADATA['localhost']['switch_type'] == 'voq' or DEVICE_METADATA['localhost']['switch_type'] == 'chassis-packet' %}
+{% if voq_chassis is defined or DEVICE_METADATA['localhost']['switch_type'] == 'chassis-packet' %}
     network {{ get_ipv6_loopback_address(LOOPBACK_INTERFACE, "Loopback0") | ip }}/128 route-map HIDE_INTERNAL
 {% endif %}
 {% endif %}
   exit-address-family
 {% endif %}
-{% if ((multi_asic is defined and DEVICE_METADATA['localhost']['switch_type'] != 'chassis-packet') or (DEVICE_METADATA['localhost']['switch_type'] == 'voq')) %}
+{% if ((multi_asic is defined and DEVICE_METADATA['localhost']['switch_type'] != 'chassis-packet') or (voq_chassis is defined)) %}
 {% if get_ipv6_loopback_address(LOOPBACK_INTERFACE, "Loopback4096") != 'None' %}
   address-family ipv6
     network {{ get_ipv6_loopback_address(LOOPBACK_INTERFACE, "Loopback4096") | ip }}/128 route-map HIDE_INTERNAL
@@ -161,7 +165,7 @@ router bgp {{ DEVICE_METADATA['localhost']['bgp_asn'] }}
 {% endblock vlan_advertisement %}
 !
 !
-{% if DEVICE_METADATA['localhost']['sub_role'] == 'FrontEnd' or DEVICE_METADATA['localhost']['switch_type'] == 'voq' or DEVICE_METADATA['localhost']['switch_type'] == 'chassis-packet' %}
+{% if DEVICE_METADATA['localhost']['sub_role'] == 'FrontEnd' or voq_chassis is defined or DEVICE_METADATA['localhost']['switch_type'] == 'chassis-packet' %}
   address-family ipv4
     redistribute connected route-map V4_CONNECTED_ROUTES
   exit-address-family

dockers/docker-fpm-frr/frr/bgpd/templates/monitors/peer-group.conf.j2

@@ -1,8 +1,12 @@
 !
 ! template: bgpd/templates/BGPMON/peer-group.conf.j2
 !
+{% if CONFIG_DB__DEVICE_METADATA['localhost']['switch_type'] == 'voq' and ('chassisdb_conf_present' in CONFIG_DB__DEVICE_METADATA['localhost'] or
+      '/usr/share/sonic/platform/chassisdb.conf' | file_exists) %}
+{% set voq_chassis = True %}
+{% endif %}
   neighbor BGPMON peer-group
-{% if CONFIG_DB__DEVICE_METADATA['localhost']['switch_type'] == 'voq' or CONFIG_DB__DEVICE_METADATA['localhost']['switch_type'] == 'chassis-packet' %}
+{% if voq_chassis is defined or CONFIG_DB__DEVICE_METADATA['localhost']['switch_type'] == 'chassis-packet' %}
   neighbor BGPMON update-source Loopback4096
 {% elif loopback0_ipv4 %}
   neighbor BGPMON update-source {{ loopback0_ipv4 | ip }}

src/sonic-bgpcfgd/bgpcfgd/template.py

@@ -3,6 +3,7 @@
 
 import jinja2
 import netaddr
+import os
 
 from .log import log_err
 
@@ -15,6 +16,7 @@ def __init__(self, template_path = '/usr/share/sonic/templates'):
         j2_env.filters['ipv4'] = self.is_ipv4
         j2_env.filters['ipv6'] = self.is_ipv6
         j2_env.filters['pfx_filter'] = self.pfx_filter
+        j2_env.filters['file_exists'] = self.file_exists_filter
         for attr in ['ip', 'network', 'prefixlen', 'netmask']:
             j2_env.filters[attr] = partial(self.prefix_attr, attr)
         self.env = j2_env
@@ -106,3 +108,7 @@ def pfx_filter(value):
             else:
                 table[key] = val
         return table
+
+    @staticmethod
+    def file_exists_filter(path):
+        return os.path.isfile(path)

src/sonic-bgpcfgd/tests/data/monitors/peer-group.conf/param_chassis.json

@@ -2,6 +2,7 @@
     "CONFIG_DB__DEVICE_METADATA": {
         "localhost": {
             "type": "SpineRouter",
+            "chassisdb_conf_present" : "true",
             "switch_type": "voq"
         }
     }

src/sonic-bgpcfgd/tests/data/sonic-cfggen/bgpd.main.conf.j2/voq_chassis.json

@@ -4,6 +4,7 @@
             "bgp_asn": "55555",
             "sub_role": "",
             "switch_type": "voq",
+            "chassisdb_conf_present" : "true",
             "type": "SpineRouter"
         }
     },

src/sonic-config-engine/sonic-cfggen

@@ -191,6 +191,9 @@ def load_namespace_config():
         if not SonicDBConfig.isInit():
             SonicDBConfig.initialize()
 
+def file_exists_filter(path):
+    return os.path.isfile(path)
+
 class FormatConverter:
     """Convert config DB based schema to legacy minigraph based schema for backward capability.
 We will move to DB schema and remove this class when the config templates are modified.
@@ -294,6 +297,7 @@ def _get_jinja2_env(paths):
     env.filters['pfx_filter'] = pfx_filter
     env.filters['ip_network'] = ip_network
     env.filters['get_primary_addr'] = get_primary_addr
+    env.filters['file_exists'] = file_exists_filter
     for attr in ['ip', 'network', 'prefixlen', 'netmask', 'broadcast']:
         env.filters[attr] = partial(prefix_attr, attr)