[multi-asic] Fixed 13137 ERR python3: :- initializeGlobalConfig: SonicDBConfig Global config is already initialized (sonic-net#18609)

* [portconfig]: Remove try exception during config_db initialization. (sonic-net#10960)

Why I did it
Provide fix for comment: https://github.com/Azure/sonic-buildimage/pull/10475/files#r847753187;
Move laoding database config to application code instead of portconfig as portconfig is used as a library.

How I did it
Remove try exception handing from portconfig.py during config_db intialization.
Move loading of database config to application that uses portconfig.py.

How to verify it
unit-test passes.
Verified that it does not cause issue during boot up of multi-asic VS image.
Verified that config_db generation was successful in multi-asic VS.

* Fix code base on the review

---------

Co-authored-by: SuvarnaMeenakshi <[email protected]>

Author: wumiaont

src/sonic-config-engine/portconfig.py

@@ -72,12 +72,7 @@ def db_connect_configdb(namespace=None):
     """
     Connect to configdb
     """
-    try:
-        if namespace is not None:
-            swsscommon.SonicDBConfig.load_sonic_global_db_config(namespace=namespace)
-        config_db = swsscommon.ConfigDBConnector(use_unix_socket_path=True, namespace=namespace)
-    except Exception as e:
-        return None
+    config_db = swsscommon.ConfigDBConnector(use_unix_socket_path=True, namespace=namespace)
     if config_db is None:
         return None
     try:

src/sonic-config-engine/sonic-cfggen

@@ -31,7 +31,7 @@ from config_samples import generate_sample_config, get_available_config
 from functools import partial
 from minigraph import minigraph_encoder, parse_xml, parse_device_desc_xml, parse_asic_sub_role, parse_asic_switch_type
 from portconfig import get_port_config, get_breakout_mode
-from sonic_py_common.multi_asic import get_asic_id_from_name, get_asic_device_id
+from sonic_py_common.multi_asic import get_asic_id_from_name, get_asic_device_id, is_multi_asic
 from sonic_py_common import device_info
 from swsscommon.swsscommon import ConfigDBConnector, SonicDBConfig, ConfigDBPipeConnector
 
@@ -137,6 +137,14 @@ def ip_network(value):
         return "Invalid ip address %s" % value
     return r_v.network
 
+def load_namespace_config():
+    if is_multi_asic():
+        if not SonicDBConfig.isGlobalInit():
+            SonicDBConfig.initializeGlobalConfig()
+    else:
+        if not SonicDBConfig.isInit():
+            SonicDBConfig.initialize()
+
 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.
@@ -301,6 +309,7 @@ def main():
         deep_update(data, hardware_data)
         if args.port_config is None:
             args.port_config = device_info.get_path_to_port_config_file(hwsku)
+        load_namespace_config()
         (ports, _, _) = get_port_config(hwsku, platform, args.port_config, asic_id)
         if ports is None:
             print('Failed to get port config', file=sys.stderr)
@@ -326,6 +335,7 @@ def main():
 
     if args.minigraph is not None:
         minigraph = args.minigraph
+        load_namespace_config()
         if platform:
             if args.port_config is not None:
                 deep_update(data, parse_xml(minigraph, platform, args.port_config, asic_name=asic_name, hwsku_config_file=args.hwsku_config))
@@ -353,7 +363,7 @@ def main():
         if args.namespace is None:
             configdb = ConfigDBPipeConnector(use_unix_socket_path=use_unix_sock, **db_kwargs)
         else:
-            SonicDBConfig.load_sonic_global_db_config(namespace=args.namespace)
+            load_namespace_config()
             configdb = ConfigDBPipeConnector(use_unix_socket_path=use_unix_sock, namespace=args.namespace, **db_kwargs)
 
         configdb.connect()
@@ -425,7 +435,7 @@ def main():
         if args.namespace is None:
             configdb = ConfigDBPipeConnector(use_unix_socket_path=True, **db_kwargs)
         else:
-            SonicDBConfig.load_sonic_global_db_config(namespace=args.namespace)
+            load_namespace_config()
             configdb = ConfigDBPipeConnector(use_unix_socket_path=True, namespace=args.namespace, **db_kwargs)
 
         configdb.connect(False)