[write_standby] update write_standby.py script (#11650)

Why I did it
The initial value has to be present for the state machines to work. In active-standby dual-tor scenario, or any hardware mux scenario, the value will be updtaed eventually with a delay.

However, in active-active dual-tor scenario, there is no other mechanism to initialize the value and get state machines started.
So this script will have to write something at start up time.

For active-active dualtor, 'active' is a more preferred initial value, the state machine will switch the state to standby soon if
link prober found link not in good state.

How I did it
Update the script to always provide initial values.

How to verify it
Tested on active-active dual-tor testbed.

Signed-off-by: Ying Xie [email protected]

files/scripts/write_standby.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 
+import argparse
 import time
 
 from sonic_py_common import logger as log
@@ -19,11 +20,13 @@ class MuxStateWriter(object):
     Class used to write standby mux state to APP DB
     """
 
-    def __init__(self):
+    def __init__(self, activeactive, activestandby):
         self.config_db_connector = None
         self.appl_db_connector = None
         self.state_db_connector = None
         self.asic_db_connector = None
+        self.default_active_active_state = activeactive
+        self.default_active_standby_state = activestandby
 
     @property
     def config_db(self):
@@ -96,14 +99,25 @@ def is_warmrestart(self):
 
         return status and value == 'true' 
 
-    def get_auto_mux_intfs(self):
+    def get_all_mux_intfs_modes(self):
         """
-        Returns a list of all mux cable interfaces that are configured to auto-switch
+        Returns a list of all mux cable interfaces, with suggested modes
+        Setting mux initial modes is crucial to kick off the statemachines,
+        have to set the modes for all mux/gRPC ports.
         """
+        intf_modes = {}
         all_intfs = self.config_db.get_table('MUX_CABLE')
-        auto_intfs = [intf for intf, status in all_intfs.items()
-                                if status['state'].lower() == 'auto']
-        return auto_intfs
+        for intf, status in all_intfs.items():
+            state = status['state'].lower()
+            if state in ['active', 'standby']:
+                intf_modes[intf] = state
+            elif state in ['auto', 'manual']:
+                if ('soc_ipv4' in status or 'soc_ipv6' in status or
+                    ('cable_type' in status and status['cable_type'] == 'active-active')):
+                    intf_modes[intf] = self.default_active_active_state
+                else:
+                    intf_modes[intf] = self.default_active_standby_state
+        return intf_modes
 
     def tunnel_exists(self):
         """
@@ -144,19 +158,26 @@ def apply_mux_config(self):
             logger.log_warning("Skip setting mux state due to ongoing warmrestart.")
             return
 
-        intfs = self.get_auto_mux_intfs()
-        state = 'standby'
+        modes = self.get_all_mux_intfs_modes()
         if self.wait_for_tunnel():
-            logger.log_warning("Applying {} state to interfaces {}".format(state, intfs))
+            logger.log_warning("Applying state to interfaces {}".format(modes))
             producer_state_table = ProducerStateTable(self.appl_db, 'MUX_CABLE_TABLE')
-            fvs = create_fvs(state=state)
 
-            for intf in intfs:
+            for intf, state in modes.items():
+                fvs = create_fvs(state=state)
                 producer_state_table.set(intf, fvs)
         else:
             logger.log_error("Timed out waiting for tunnel {}, mux state will not be written".format(self.tunnel_name))
 
 
 if __name__ == '__main__':
-    mux_writer = MuxStateWriter()
+    parser = argparse.ArgumentParser(description='Write initial mux state')
+    parser.add_argument('-a', '--active_active',
+                        help='state: intial state for "auto" and/or "manual" config in active-active mode, default "active"',
+                        type=str, required=False, default='active')
+    parser.add_argument('-s', '--active_standby',
+                        help='state: intial state for "auto" and/or "manual" config in active-standby mode, default "standby"',
+                        type=str, required=False, default='standby')
+    args = parser.parse_args()
+    mux_writer = MuxStateWriter(activeactive=args.active_active, activestandby=args.active_standby)
     mux_writer.apply_mux_config()