[sonic-package-manager] do not modify config_db.json (#3032)

What I did
Installing an app.ext currently inserts app.ext specific init config into redis CONFIG_DB, /etc/sonic/config_db.json and /etc/sonic/init_cfg.json.

Since on configuration reload and boot the configuration file is merged with /etc/sonic/init_cfg.json there is no point in modifying config_db.json.

This can cause issues when config_db.json is not up-to-date. This is not a problem to configuration reload due to config migration, but it is not a valid JSON according to YANG model which does not validate old schema.

How I did it
Removed the relevant part of the code.

How to verify it
Verified by ONIE installing SONiC and installing an extension. Previosuly it failed and complaining about config_db.json not being valid:

Leafref "../../LOOPBACK_INTERFACE_LIST/name" of value "Loopback0" points to a non-existing leaf.
This is due to missing "Loopback0": {} in the LOOPBACK_INTERFACE table. This is not a problem since db_migrator can deal with it.

With this change, this is fixed - config_db.json is not modified, however app.ext initial configuration is inserted into redis CONFIG_DB after configuration reload or reboot.

Signed-off-by: Stepan Blyschak <[email protected]>

Author: stepanblyschak

sonic_package_manager/service_creator/sonic_db.py

@@ -12,7 +12,6 @@
 from sonic_package_manager.service_creator.utils import in_chroot
 
 CONFIG_DB = 'CONFIG_DB'
-CONFIG_DB_JSON = os.path.join(ETC_SONIC_PATH, 'config_db.json')
 INIT_CFG_JSON = os.path.join(ETC_SONIC_PATH, 'init_cfg.json')
 
 
@@ -99,12 +98,9 @@ def get_connectors(cls):
         """ Yields available DBs connectors. """
 
         initial_db_conn = cls.get_initial_db_connector()
-        persistent_db_conn = cls.get_persistent_db_connector()
         running_db_conn = cls.get_running_db_connector()
 
         yield initial_db_conn
-        if persistent_db_conn is not None:
-            yield persistent_db_conn
         if running_db_conn is not None:
             yield running_db_conn
 
@@ -127,15 +123,6 @@ def get_running_db_connector(cls):
 
         return cls._running_db_conn
 
-    @classmethod
-    def get_persistent_db_connector(cls):
-        """ Returns persistent DB connector. """
-
-        if not os.path.exists(CONFIG_DB_JSON):
-            return None
-
-        return PersistentConfigDbConnector(CONFIG_DB_JSON)
-
     @classmethod
     def get_initial_db_connector(cls):
         """ Returns initial DB connector. """