fix: skip file opened event for template watcher

samcli/lib/utils/resource_trigger.py

@@ -1,13 +1,14 @@
 """ResourceTrigger Classes for Creating PathHandlers According to a Resource"""
 
+import logging
 import platform
 import re
 from abc import ABC, abstractmethod
 from pathlib import Path
 from typing import Any, Dict, List, Optional, cast
 
 from typing_extensions import Protocol
-from watchdog.events import FileSystemEvent, RegexMatchingEventHandler
+from watchdog.events import EVENT_TYPE_OPENED, FileSystemEvent, RegexMatchingEventHandler
 
 from samcli.lib.providers.exceptions import InvalidTemplateFile, MissingCodeUri, MissingLocalDefinition
 from samcli.lib.providers.provider import Function, LayerVersion, ResourceIdentifier, Stack, get_resource_by_id
@@ -18,6 +19,9 @@
 from samcli.lib.utils.resources import RESOURCES_WITH_LOCAL_PATHS
 from samcli.local.lambdafn.exceptions import FunctionNotFound, ResourceNotFound
 
+LOG = logging.getLogger(__name__)
+
+
 DEFAULT_WATCH_IGNORED_RESOURCES = ["^.*\\.aws-sam.*$", "^.*node_modules.*$"]
 
 
@@ -134,6 +138,15 @@ def _validator_wrapper(self, event: Optional[FileSystemEvent] = None) -> None:
         ----------
         event : Optional[FileSystemEvent], optional
         """
+        if event and event.event_type == EVENT_TYPE_OPENED:
+            # Ignore all file opened events since this event is
+            # added in addition to a create or modified event,
+            # causing an infinite loop of sync flow creations
+            LOG.debug("Ignoring file system OPENED event")
+            return
+        LOG.debug(
+            "Template watcher (%s) for stack (%s) got file event %s", self._template_file, self._stack_name, event
+        )
         if self._validator.validate_change():
             self._on_template_change(event)
 

tests/unit/lib/utils/test_resource_trigger.py

@@ -2,6 +2,7 @@
 from parameterized import parameterized
 from unittest.case import TestCase
 from unittest.mock import MagicMock, Mock, patch, ANY
+from watchdog.events import EVENT_TYPE_OPENED
 from samcli.lib.utils.resource_trigger import (
     DEFAULT_WATCH_IGNORED_RESOURCES,
     CodeResourceTrigger,
@@ -92,6 +93,18 @@ def test_validator_wrapper(self, path_mock, validator_mock):
         trigger._validator_wrapper(event_mock)
         on_template_change_mock.assert_called_once_with(event_mock)
 
+    @patch("samcli.lib.utils.resource_trigger.DefinitionValidator")
+    @patch("samcli.lib.utils.resource_trigger.Path")
+    def test_validator_wrapper_for_file_opened_event(self, path_mock, validator_mock):
+        validator_mock.return_value.raw_validate.return_value = True
+        on_template_change_mock = MagicMock()
+        event_mock = MagicMock()
+        event_mock.event_type = EVENT_TYPE_OPENED
+        validator_mock.return_value.raw_validate.return_value = True
+        trigger = TemplateTrigger("template.yaml", "stack", on_template_change_mock)
+        trigger._validator_wrapper(event_mock)
+        on_template_change_mock.assert_not_called()
+
 
 class TestCodeResourceTrigger(TestCase):
     @patch.multiple(CodeResourceTrigger, __abstractmethods__=set())