fix: add a lock check on starter project initialization (#8631)

* Adds a lock check on starter project initialization

* [autofix.ci] apply automated fixes

* ruff fix for exception

* [autofix.ci] apply automated fixes

* Adds a lock check on starter project initialization

* [autofix.ci] apply automated fixes

* fix: Improve logging for lock acquisition failures in starter project creation

* [autofix.ci] apply automated fixes

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Gabriel Luiz Freitas Almeida <gabriel@langflow.org>

pyproject.toml

@@ -124,7 +124,9 @@ dependencies = [
     "cleanlab-tlm>=1.1.2",
     'gassist>=0.0.1; sys_platform == "win32"',
     "twelvelabs>=0.4.7",
+    "filelock>=3.18.0",
     "docling>=2.36.1",
+    "filelock>=3.18.0"
 ]
 
 [dependency-groups]

src/backend/base/langflow/initial_setup/starter_projects/Memory Chatbot.json

@@ -26,9 +26,9 @@
         "id": "xy-edge__Memory-hMFmY{œdataTypeœ:œMemoryœ,œidœ:œMemory-hMFmYœ,œnameœ:œmessages_textœ,œoutput_typesœ:[œMessageœ]}-Prompt-CixsJ{œfieldNameœ:œmemoryœ,œidœ:œPrompt-CixsJœ,œinputTypesœ:[œMessageœ,œTextœ],œtypeœ:œstrœ}",
         "selected": false,
         "source": "Memory-hMFmY",
-        "sourceHandle": "{œdataTypeœ:œMemoryœ,œidœ:œMemory-hMFmYœ,œnameœ:œmessages_textœ,œoutput_typesœ:[œMessageœ]}",
+        "sourceHandle": "{œdataTypeœ: œMemoryœ, œidœ: œMemory-hMFmYœ, œnameœ: œmessages_textœ, œoutput_typesœ: [œMessageœ]}",
         "target": "Prompt-CixsJ",
-        "targetHandle": "{œfieldNameœ:œmemoryœ,œidœ:œPrompt-CixsJœ,œinputTypesœ:[œMessageœ,œTextœ],œtypeœ:œstrœ}"
+        "targetHandle": "{œfieldNameœ: œmemoryœ, œidœ: œPrompt-CixsJœ, œinputTypesœ: [œMessageœ, œTextœ], œtypeœ: œstrœ}"
       },
       {
         "animated": false,
@@ -54,9 +54,9 @@
         "id": "xy-edge__Prompt-CixsJ{œdataTypeœ:œPromptœ,œidœ:œPrompt-CixsJœ,œnameœ:œpromptœ,œoutput_typesœ:[œMessageœ]}-LanguageModelComponent-vvfAj{œfieldNameœ:œsystem_messageœ,œidœ:œLanguageModelComponent-vvfAjœ,œinputTypesœ:[œMessageœ],œtypeœ:œstrœ}",
         "selected": false,
         "source": "Prompt-CixsJ",
-        "sourceHandle": "{œdataTypeœ:œPromptœ,œidœ:œPrompt-CixsJœ,œnameœ:œpromptœ,œoutput_typesœ:[œMessageœ]}",
+        "sourceHandle": "{œdataTypeœ: œPromptœ, œidœ: œPrompt-CixsJœ, œnameœ: œpromptœ, œoutput_typesœ: [œMessageœ]}",
         "target": "LanguageModelComponent-vvfAj",
-        "targetHandle": "{œfieldNameœ:œsystem_messageœ,œidœ:œLanguageModelComponent-vvfAjœ,œinputTypesœ:[œMessageœ],œtypeœ:œstrœ}"
+        "targetHandle": "{œfieldNameœ: œsystem_messageœ, œidœ: œLanguageModelComponent-vvfAjœ, œinputTypesœ: [œMessageœ], œtypeœ: œstrœ}"
       },
       {
         "animated": false,
@@ -82,9 +82,9 @@
         "id": "xy-edge__ChatInput-5t3wq{œdataTypeœ:œChatInputœ,œidœ:œChatInput-5t3wqœ,œnameœ:œmessageœ,œoutput_typesœ:[œMessageœ]}-LanguageModelComponent-vvfAj{œfieldNameœ:œinput_valueœ,œidœ:œLanguageModelComponent-vvfAjœ,œinputTypesœ:[œMessageœ],œtypeœ:œstrœ}",
         "selected": false,
         "source": "ChatInput-5t3wq",
-        "sourceHandle": "{œdataTypeœ:œChatInputœ,œidœ:œChatInput-5t3wqœ,œnameœ:œmessageœ,œoutput_typesœ:[œMessageœ]}",
+        "sourceHandle": "{œdataTypeœ: œChatInputœ, œidœ: œChatInput-5t3wqœ, œnameœ: œmessageœ, œoutput_typesœ: [œMessageœ]}",
         "target": "LanguageModelComponent-vvfAj",
-        "targetHandle": "{œfieldNameœ:œinput_valueœ,œidœ:œLanguageModelComponent-vvfAjœ,œinputTypesœ:[œMessageœ],œtypeœ:œstrœ}"
+        "targetHandle": "{œfieldNameœ: œinput_valueœ, œidœ: œLanguageModelComponent-vvfAjœ, œinputTypesœ: [œMessageœ], œtypeœ: œstrœ}"
       },
       {
         "animated": false,
@@ -112,9 +112,9 @@
         "id": "xy-edge__LanguageModelComponent-vvfAj{œdataTypeœ:œLanguageModelComponentœ,œidœ:œLanguageModelComponent-vvfAjœ,œnameœ:œtext_outputœ,œoutput_typesœ:[œMessageœ]}-ChatOutput-CwxcD{œfieldNameœ:œinput_valueœ,œidœ:œChatOutput-CwxcDœ,œinputTypesœ:[œDataœ,œDataFrameœ,œMessageœ],œtypeœ:œstrœ}",
         "selected": false,
         "source": "LanguageModelComponent-vvfAj",
-        "sourceHandle": "{œdataTypeœ:œLanguageModelComponentœ,œidœ:œLanguageModelComponent-vvfAjœ,œnameœ:œtext_outputœ,œoutput_typesœ:[œMessageœ]}",
+        "sourceHandle": "{œdataTypeœ: œLanguageModelComponentœ, œidœ: œLanguageModelComponent-vvfAjœ, œnameœ: œtext_outputœ, œoutput_typesœ: [œMessageœ]}",
         "target": "ChatOutput-CwxcD",
-        "targetHandle": "{œfieldNameœ:œinput_valueœ,œidœ:œChatOutput-CwxcDœ,œinputTypesœ:[œDataœ,œDataFrameœ,œMessageœ],œtypeœ:œstrœ}"
+        "targetHandle": "{œfieldNameœ: œinput_valueœ, œidœ: œChatOutput-CwxcDœ, œinputTypesœ: [œDataœ, œDataFrameœ, œMessageœ], œtypeœ: œstrœ}"
       }
     ],
     "nodes": [
@@ -1006,6 +1006,7 @@
                 "group_outputs": false,
                 "method": "retrieve_messages_dataframe",
                 "name": "dataframe",
+                "selected": null,
                 "tool_mode": true,
                 "types": [
                   "DataFrame"

src/backend/base/langflow/main.py

@@ -154,10 +154,31 @@ def get_lifespan(*, fix_migration=False, version=None):
             all_types_dict = await get_and_cache_all_types_dict(get_settings_service())
             logger.debug(f"Types cached in {asyncio.get_event_loop().time() - current_time:.2f}s")
 
+            # Use file-based lock to prevent multiple workers from creating duplicate starter projects concurrently.
+            # Note that it's still possible that one worker may complete this task, release the lock,
+            # then another worker pick it up, but the operation is idempotent so worst case it duplicates
+            # the initialization work.
             current_time = asyncio.get_event_loop().time()
             logger.debug("Creating/updating starter projects")
-            await create_or_update_starter_projects(all_types_dict)
-            logger.debug(f"Starter projects updated in {asyncio.get_event_loop().time() - current_time:.2f}s")
+            import tempfile
+
+            from filelock import FileLock
+
+            lock_file = Path(tempfile.gettempdir()) / "langflow_starter_projects.lock"
+            lock = FileLock(lock_file, timeout=1)
+            try:
+                with lock:
+                    await create_or_update_starter_projects(all_types_dict)
+                    logger.debug(
+                        f"Starter projects created/updated in {asyncio.get_event_loop().time() - current_time:.2f}s"
+                    )
+            except TimeoutError:
+                # Another process has the lock
+                logger.debug("Another worker is creating starter projects, skipping")
+            except Exception as e:  # noqa: BLE001
+                logger.warning(
+                    f"Failed to acquire lock for starter projects: {e}. Starter projects may not be created or updated."
+                )
 
             current_time = asyncio.get_event_loop().time()
             logger.debug("Starting telemetry service")