Add support for static route expiry (#12712)

* add support for static route expiry

* fix debug info

* fix a format issue

src/sonic-bgpcfgd/bgpcfgd/main.py

@@ -2,6 +2,7 @@ import os
 import signal
 import sys
 import syslog
+import threading
 import traceback
 
 from swsscommon import swsscommon
@@ -19,15 +20,18 @@ from .managers_setsrc import ZebraSetSrc
 from .managers_static_rt import StaticRouteMgr
 from .managers_rm import RouteMapMgr
 from .managers_device_global import DeviceGlobalCfgMgr
+from .static_rt_timer import StaticRouteTimer
 from .runner import Runner, signal_handler
 from .template import TemplateFabric
 from .utils import read_constants
 from .frr import FRR
 from .vars import g_debug
 
-
 def do_work():
     """ Main function """
+    st_rt_timer = StaticRouteTimer()
+    thr = threading.Thread(target = st_rt_timer.run)
+    thr.start()
     frr = FRR(["bgpd", "zebra", "staticd"])
     frr.wait_for_daemons(seconds=20)
     #
@@ -62,6 +66,7 @@ def do_work():
         BBRMgr(common_objs, "CONFIG_DB", "BGP_BBR"),
         # Static Route Managers
         StaticRouteMgr(common_objs, "CONFIG_DB", "STATIC_ROUTE"),
+        StaticRouteMgr(common_objs, "APPL_DB", "STATIC_ROUTE"),
         # Route Advertisement Managers
         AdvertiseRouteMgr(common_objs, "STATE_DB", swsscommon.STATE_ADVERTISE_NETWORK_TABLE_NAME),
         RouteMapMgr(common_objs, "APPL_DB", swsscommon.APP_BGP_PROFILE_TABLE_NAME),
@@ -72,6 +77,7 @@ def do_work():
     for mgr in managers:
         runner.add_manager(mgr)
     runner.run()
+    thr.join()
 
 
 def main():

src/sonic-bgpcfgd/bgpcfgd/managers_static_rt.py

@@ -4,6 +4,7 @@ from .manager import Manager
 from .template import TemplateFabric
 import socket
 from swsscommon import swsscommon
+from ipaddress import ip_network, IPv4Network
 
 class StaticRouteMgr(Manager):
     """ This class updates static routes when STATIC_ROUTE table is updated """
@@ -96,11 +97,28 @@ class StaticRouteMgr(Manager):
         Split key into vrf name and prefix.
         :param key: key to split
         :return: vrf name extracted from the key, ip prefix extracted from the key
+        key example: APPL_DB   vrf:5.5.5.0/24, 5.5.5.0/24, vrf:2001::0/64, 2001::0/64
+                     CONFIG_DB vrf|5.5.5.0/24, 5.5.5.0/24, vrf|2001::0/64, 2001::0/64
         """
-        if '|' not in key:
-            return 'default', key
-        else:
+        vrf = ""
+        prefix = ""
+
+        if '|' in key:
             return tuple(key.split('|', 1))
+        else:
+            try:
+                _ = ip_network(key)
+                vrf, prefix = 'default', key
+            except ValueError:
+                # key in APPL_DB
+                log_debug("static route key {} is not prefix only formart, split with ':'".format(key))
+                output = key.split(':', 1)
+                if len(output) < 2:
+                    log_debug("invalid input in APPL_DB {}".format(key))
+                    raise ValueError
+                vrf = output[0]
+                prefix = key[len(vrf)+1:]
+        return vrf, prefix
 
     def static_route_commands(self, ip_nh_set, cur_nh_set, ip_prefix, vrf, route_tag, cur_route_tag):
         op_cmd_list = {}

src/sonic-bgpcfgd/bgpcfgd/static_rt_timer.py

@@ -0,0 +1,57 @@
+from .log import log_err, log_info, log_debug
+from swsscommon import swsscommon
+import time
+
+class StaticRouteTimer(object):
+    """ This class checks the static routes and deletes those entries that have not been refreshed """
+    def __init__(self):
+        self.db = swsscommon.SonicV2Connector()
+        self.db.connect(self.db.APPL_DB)
+        self.timer = None
+        self.start = None
+
+    DEFAULT_TIMER = 180
+    DEFAULT_SLEEP = 60
+    MAX_TIMER     = 1800
+
+    def set_timer(self):
+        """ Check for custom route expiry time in STATIC_ROUTE:EXPIRY_TIME """
+        timer = self.db.get(self.db.APPL_DB, "STATIC_ROUTE_EXPIRY_TIME", "time")
+        if timer is not None:
+            timer = int(timer)     
+            if timer > 0 and timer <= self.MAX_TIMER:
+                self.timer = timer
+                return
+            log_err("Custom static route expiry time of {}s is invalid!".format(timer))
+        return
+
+    def alarm(self):
+        """ Clear unrefreshed static routes """
+        static_routes = self.db.keys(self.db.APPL_DB, "STATIC_ROUTE:*")
+        if static_routes is not None:
+            for sr in static_routes:
+                expiry = self.db.get(self.db.APPL_DB, sr, "expiry")
+                if expiry == "false":
+                    continue
+                refresh = self.db.get(self.db.APPL_DB, sr, "refresh")
+                if refresh == "true":
+                    self.db.set(self.db.APPL_DB, sr, "refresh", "false")
+                    log_debug("Refresh status of static route {} is set to false".format(sr))
+                else:
+                    self.db.delete(self.db.APPL_DB, sr)
+                    log_debug("Static route {} deleted".format(sr))
+        self.start = time.time()
+        return
+
+    def run(self):
+        self.start = time.time()
+        while True:
+            self.set_timer()
+            if self.timer:
+                log_info("Static route expiry set to {}s".format(self.timer))
+                time.sleep(self.timer)
+                self.alarm()
+            else:
+                time.sleep(self.DEFAULT_SLEEP)
+                if time.time() - self.start >= self.DEFAULT_TIMER:
+                    self.alarm()