[sonic-package-manager] do not mod_config for whole config db when se…

…tting init_cfg (#2055)

What I did
conn.mod_config(new_cfg) modifies entries which where not changed in new_cfg.
This causes errors when installing/upgrading extension like, because mod_config pushes the same configuration again:

"ERR swss#orchagent: :- addOperation: Vxlan tunnel 'tunnel1' is already exists” in syslog
I made a change so that when setting init configuration for an extension we are not modifying the whole DB.

How I did it
Perform a conn.mod_entry for entries from init configuration of the package.

How to verify it
Run UT. Make sure no errors when installing extension and having vxlan configuration in config db.
Signed-off-by: Stepan Blyschak <stepanb@nvidia.com>

sonic_package_manager/service_creator/creator.py

@@ -491,12 +491,22 @@ def set_initial_config(self, package):
         if not init_cfg:
             return
 
+        def update_config_with_init_cfg(cfg, conn):
+            for table, content in init_cfg.items():
+                if not isinstance(content, dict):
+                    continue
+
+                for key, fvs in content.items():
+                    key_cfg = cfg.get(table, {}).get(key, {})
+                    key_cfg.update(fvs)
+                    conn.mod_entry(table, key, key_cfg)
+
         for conn in self.sonic_db.get_connectors():
             cfg = conn.get_config()
             new_cfg = init_cfg.copy()
             utils.deep_update(new_cfg, cfg)
             self.validate_config(new_cfg)
-            conn.mod_config(new_cfg)
+            update_config_with_init_cfg(cfg, conn)
 
     def remove_config(self, package):
         """ Remove configuration based on package YANG module.

tests/sonic_package_manager/test_service_creator.py

@@ -131,7 +131,9 @@ def test_service_creator_yang(sonic_fs, manifest, mock_sonic_db,
     mock_sonic_db.get_connectors = Mock(return_value=[mock_connector])
     mock_connector.get_table = Mock(return_value={'key_a': {'field_1': 'value_1'}})
     mock_connector.get_config = Mock(return_value={
-        'TABLE_A': mock_connector.get_table('')
+        'TABLE_A': mock_connector.get_table(''),
+        'TABLE_B': mock_connector.get_table(''),
+        'TABLE_C': mock_connector.get_table(''),
     })
 
     entry = PackageEntry('test', 'azure/sonic-test')
@@ -155,15 +157,8 @@ def test_service_creator_yang(sonic_fs, manifest, mock_sonic_db,
 
     mock_config_mgmt.add_module.assert_called_with(test_yang)
 
-    mock_connector.mod_config.assert_called_with(
-        {
-            'TABLE_A': {
-                'key_a': {
-                    'field_1': 'value_1',
-                    'field_2': 'value_2',
-                },
-            },
-        }
+    mock_connector.mod_entry.assert_called_once_with(
+        'TABLE_A', 'key_a', {'field_1': 'value_1', 'field_2': 'value_2'}
     )
 
     mock_config_mgmt.sy.confDbYangMap = {