Update for the Procedures for insertion/hot swap of Switch Fabric Mod…

…ule (SFM)

1. Add chassis_module_config.py and its service.
2. When the cli command "sudo config chassis modules startup/shutdown" runs,
   calls chassis_module_set_admin_state.py to do the ralated operations.

files/build_templates/chassis-module.service

@@ -0,0 +1,18 @@
+[Unit]
+Description=Chassis module up & down operation
+ConditionPathExists=/etc/sonic/chassisdb.conf
+Requires=database.service updategraph.service
+After=database.service updategraph.service
+StartLimitIntervalSec=1200
+StartLimitBurst=3
+BindsTo=sonic.target
+After=sonic.target
+
+[Service]
+User=root
+ExecStart=/usr/bin/python3 /usr/local/bin/chassis_module_config.py
+ExecStop=/bin/kill -SIGINT $MAINPID
+RestartSec=30
+
+[Install]
+WantedBy=multi-user.target

files/build_templates/sonic_debian_extension.j2

@@ -963,6 +963,7 @@ sudo LANG=C cp $SCRIPTS_DIR/gnmi.sh $FILESYSTEM_ROOT/usr/local/bin/gnmi.sh
 sudo LANG=C cp $SCRIPTS_DIR/mgmt-framework.sh $FILESYSTEM_ROOT/usr/local/bin/mgmt-framework.sh
 sudo LANG=C cp $SCRIPTS_DIR/asic_status.sh $FILESYSTEM_ROOT/usr/local/bin/asic_status.sh
 sudo LANG=C cp $SCRIPTS_DIR/asic_status.py $FILESYSTEM_ROOT/usr/local/bin/asic_status.py
+sudo LANG=C cp $SCRIPTS_DIR/chassis_module_config.py $FILESYSTEM_ROOT/usr/local/bin/chassis_module_config.py
 
 # Copy sonic-netns-exec script
 sudo LANG=C cp $SCRIPTS_DIR/sonic-netns-exec $FILESYSTEM_ROOT/usr/bin/sonic-netns-exec

files/scripts/chassis_module_config.py

@@ -0,0 +1,80 @@
+#!/usr/bin/env python3
+
+"""
+    Chassis module config
+"""
+try:
+    import sys
+    import os
+    import subprocess
+    from sonic_py_common import daemon_base
+    from swsscommon import swsscommon
+    from sonic_py_common.logger import Logger
+except ImportError as e:
+    raise ImportError(str(e) + " - required module wasn't found")
+
+#
+# Constants ====================================================================
+#
+SYSLOG_IDENTIFIER = 'chassis_module_config.py'
+CHASSIS_MODULE= 'CHASSIS_MODULE'
+SELECT_TIMEOUT_MSECS = 5000
+CHASSIS_MODULE_SET_ADMIN_STATE = '/usr/local/bin/chassis_module_set_admin_state.py'
+
+def main():
+    logger = Logger(SYSLOG_IDENTIFIER)
+    logger.set_min_log_priority_info()
+
+    # dict
+    current_module_state = dict()
+
+    # Connect to STATE_DB and subscribe to chassis-module table notifications
+    cfg_db = daemon_base.db_connect("CONFIG_DB")
+
+    sel = swsscommon.Select()
+    sst = swsscommon.SubscriberStateTable(cfg_db, CHASSIS_MODULE)
+    sel.addSelectable(sst)
+
+    while True:
+        (state, c) = sel.select(SELECT_TIMEOUT_MSECS)
+        if state == swsscommon.Select.TIMEOUT:
+            continue
+
+        (module_name, module_op, module_fvp) = sst.pop()
+
+        state = current_module_state.get(module_name)
+        module_fvs = dict(module_fvp)
+        new_state = module_fvs.get('admin_status')
+
+        if module_op == 'SET':
+            if new_state is None:
+                continue
+
+            if state != new_state:
+                if new_state == "down":
+                    current_module_state[module_name] = "down"
+                else:
+                    current_module_state.pop(module_name, None)
+
+                if os.path.exists(CHASSIS_MODULE_SET_ADMIN_STATE):
+                    subprocess.run(['python3', CHASSIS_MODULE_SET_ADMIN_STATE, module_name, new_state])
+                else:
+                    logger.log_error("{} doesn't exist.".format(CHASSIS_MODULE_SET_ADMIN_STATE))
+
+        elif module_op == 'DEL':
+            if new_state is None:
+                new_state = 'up'
+
+            if state != new_state:
+                if new_state == "up":
+                    current_module_state[module_name] = "up"
+                else:
+                    current_module_state.pop(module_name, None)
+
+                if os.path.exists(CHASSIS_MODULE_SET_ADMIN_STATE):
+                    subprocess.run(['python3', CHASSIS_MODULE_SET_ADMIN_STATE, module_name, new_state])
+                else:
+                    logger.log_error("{} doesn't exist.".format(CHASSIS_MODULE_SET_ADMIN_STATE))
+
+if __name__ == "__main__":
+    main()