[Mellanox] Added inotify mechanism for vpd_data file creation

platform/mellanox/mlnx-platform-api/sonic_platform/chassis.py

@@ -50,6 +50,7 @@
 
 VPD_DATA_FILE = "/var/run/hw-management/eeprom/vpd_data"
 REVISION = "REV"
+VPD_DATA_WAIT_TIMEOUT = 60  # Timeout in seconds for waiting for VPD data file
 
 HWMGMT_SYSTEM_ROOT = '/var/run/hw-management/system/'
 
@@ -1066,7 +1067,10 @@ def _parse_vpd_data(self, filename):
         result = {}
         try:
             if not os.access(filename, os.R_OK):
-                return result
+                logger.log_info("VPD data file {} not accessible, waiting for creation".format(filename))
+                if not utils.wait_for_file_creation(filename, VPD_DATA_WAIT_TIMEOUT):
+                    logger.log_error("VPD data file {} not available after timeout".format(filename))
+                    return result
 
             result = utils.read_key_value_file(filename, delimeter=": ")
 

platform/mellanox/mlnx-platform-api/sonic_platform/utils.py

@@ -24,6 +24,12 @@
 import threading
 import time
 import os
+
+# Inotify causes an exception when DEBUG env variable is set to a non-integer convertible
+# https://github.com/dsoprea/PyInotify/blob/0.2.10/inotify/adapters.py#L37
+os.environ['DEBUG'] = '0'
+import inotify.adapters
+import inotify.constants
 from sonic_py_common import device_info
 from sonic_py_common.logger import Logger
 
@@ -299,6 +305,53 @@ def extract_cpo_ports_index(num_of_asics=1):
     return _extract_ports_index_by_type(CPO_PORT_TYPE, num_of_asics)
 
 
+# Use this function only for files that have user read permission.
+def wait_for_file_creation(file_path, timeout):
+    """
+    Wait for a file to be created using inotify
+
+    Args:
+        file_path: Path to the file to wait for
+        timeout: Timeout in seconds
+
+    Returns:
+        True if file was created/copied from a temporary file, and is readable, False otherwise
+    """
+    # If file already exists and is readable, return immediately
+    if os.access(file_path, os.R_OK):
+        return True
+
+    dir_path = os.path.dirname(file_path)
+    file_name = os.path.basename(file_path)
+
+    if not os.path.exists(dir_path):
+        logger.log_debug("Directory {} does not exist".format(dir_path))
+        return False
+
+    try:
+        notifier = inotify.adapters.Inotify()
+        notifier.add_watch(dir_path,
+                           mask=(inotify.constants.IN_CREATE
+                                 | inotify.constants.IN_CLOSE_WRITE
+                                 | inotify.constants.IN_MOVED_TO))
+
+        for event in notifier.event_gen(timeout_s=timeout, yield_nones=False):
+            (_, type_names, path, filename) = event
+            if filename == file_name:
+                if "IN_CREATE" in type_names or "IN_CLOSE_WRITE" in type_names or "IN_MOVED_TO" in type_names:
+                    if os.access(file_path, os.R_OK):
+                        logger.log_info("File {} created and readable".format(file_path))
+                        return True
+
+    except Exception as e:
+        logger.log_error("Inotify error while waiting for {}: {}".format(file_path, repr(e)))
+
+    if os.access(file_path, os.R_OK):
+        return True
+
+    return False
+
+
 def extract_asic_id_map(num_of_asics=1):
     asic_id_map = {}
 

platform/mellanox/mlnx-platform-api/tests/test_utils.py

@@ -1,6 +1,6 @@
 #
 # SPDX-FileCopyrightText: NVIDIA CORPORATION & AFFILIATES
-# Copyright (c) 2021-2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# Copyright (c) 2021-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 # Apache-2.0
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -327,6 +327,59 @@ def test_wait_until_conditions(self):
         conditions = [lambda: False]
         assert not utils.wait_until_conditions(conditions, 1)
 
+    @mock.patch('sonic_platform.utils.inotify.adapters.Inotify')
+    @mock.patch('os.access')
+    def test_wait_for_file_creation_immediate(self, mock_access, mock_inotify):
+        mock_access.return_value = True
+        assert utils.wait_for_file_creation('/tmp/test.file', timeout=1)
+        mock_inotify.assert_not_called()
+
+    @mock.patch('sonic_platform.utils.logger.log_debug')
+    @mock.patch('os.path.exists')
+    @mock.patch('os.access')
+    def test_wait_for_file_creation_dir_missing(self, mock_access, mock_exists, mock_log_debug):
+        """When directory does not exist, return False immediately (no wait)."""
+        mock_access.return_value = False
+        mock_exists.return_value = False
+        assert not utils.wait_for_file_creation('/tmp/test.file', timeout=1)
+        mock_log_debug.assert_called_once()
+
+    @pytest.mark.parametrize("event_type", [
+        "IN_CREATE",
+        "IN_CLOSE_WRITE",
+        "IN_MOVED_TO",
+    ])
+    @mock.patch('sonic_platform.utils.logger.log_info')
+    @mock.patch('os.path.exists')
+    @mock.patch('os.access')
+    def test_wait_for_file_creation_inotify_event(self, mock_access, mock_exists, mock_log_info, event_type):
+        """All inotify event types that indicate file creation are handled."""
+        # First os.access: file not readable at start; second: readable when inotify event is processed
+        mock_access.side_effect = [False, True]
+        mock_exists.return_value = True
+
+        mock_notifier = mock.MagicMock()
+        mock_notifier.event_gen.return_value = [
+            (None, [event_type], "/tmp", "test.file")
+        ]
+
+        with mock.patch('sonic_platform.utils.inotify.adapters.Inotify', return_value=mock_notifier):
+            assert utils.wait_for_file_creation('/tmp/test.file', timeout=1)
+
+        mock_log_info.assert_called_once()
+
+    @mock.patch('sonic_platform.utils.logger.log_error')
+    @mock.patch('os.path.exists')
+    @mock.patch('os.access')
+    def test_wait_for_file_creation_inotify_error(self, mock_access, mock_exists, mock_log_error):
+        mock_access.side_effect = [False, False]
+        mock_exists.return_value = True
+
+        with mock.patch('sonic_platform.utils.inotify.adapters.Inotify', side_effect=Exception('boom')):
+            assert not utils.wait_for_file_creation('/tmp/test.file', timeout=1)
+
+        mock_log_error.assert_called_once()
+
     def test_timer(self):
         timer = utils.Timer()
         timer.start()