[sonic-py-common] Add platform.json to port_config files candidates o…

…nly if interfaces are present within platform.json (sonic-net#5538)

* [sonic-py-common] add platform.json to port_config

Signed-off-by: vaibhav-dahiya <[email protected]>

src/sonic-py-common/sonic_py_common/device_info.py

@@ -1,4 +1,5 @@
 import glob
+import json
 import os
 import re
 import subprocess
@@ -255,8 +256,21 @@ def get_path_to_port_config_file(hwsku=None, asic=None):
 
     # if 'hwsku.json' file is available, Check for 'platform.json' file presence,
     # if 'platform.json' is available, APPEND it. Otherwise, SKIP it.
+
+    """
+    This length check for interfaces in platform.json is performed to make sure
+    the cfggen does not fail if port configuration information is not present
+    TODO: once platform.json has all the necessary port config information
+          remove this check
+    """
+
     if os.path.isfile(hwsku_json_file):
-        port_config_candidates.append(os.path.join(platform_path, PLATFORM_JSON_FILE))
+        if os.path.isfile(os.path.join(platform_path, PLATFORM_JSON_FILE)):
+            json_file = os.path.join(platform_path, PLATFORM_JSON_FILE)
+            platform_data = json.loads(open(json_file).read())
+            interfaces = platform_data.get('interfaces', None)
+            if interfaces is not None and len(interfaces) > 0:
+                port_config_candidates.append(os.path.join(platform_path, PLATFORM_JSON_FILE))
 
     # Check for 'port_config.ini' file presence in a few locations
     if asic: