fix: environment variable initialization issue (#2971)

* feat: apply singleton pattern to class

* fix: remove code that overrides environment vars

* feat: remove unused imports

src/backend/base/langflow/__main__.py

@@ -4,12 +4,12 @@ import sys
 import time
 import warnings
 from pathlib import Path
-from typing import Any, Callable, Optional
+from typing import Optional
 
 import click
 import httpx
 import typer
-from dotenv import dotenv_values, load_dotenv
+from dotenv import load_dotenv
 from multiprocess import cpu_count  # type: ignore
 from multiprocess.context import Process  # type: ignore
 from packaging import version as pkg_version
@@ -127,33 +127,9 @@ def run(
 
     configure(log_level=log_level, log_file=log_file)
     set_var_for_macos_issue()
-    # override env variables with .env file
 
     if env_file:
         load_dotenv(env_file, override=True)
-        env_vars = dotenv_values(env_file)
-
-        # Define a mapping of environment variables to their corresponding variables and types
-        env_var_mapping: dict[str, tuple[str, type | Callable[[Any], bool]]] = {
-            "LANGFLOW_HOST": ("host", str),
-            "LANGFLOW_PORT": ("port", int),
-            "LANGFLOW_WORKERS": ("workers", int),
-            "LANGFLOW_WORKER_TIMEOUT": ("timeout", int),
-            "LANGFLOW_COMPONENTS_PATH": ("components_path", Path),
-            "LANGFLOW_LOG_LEVEL": ("log_level", str),
-            "LANGFLOW_LOG_FILE": ("log_file", Path),
-            "LANGFLOW_LANGCHAIN_CACHE": ("cache", str),
-            "LANGFLOW_FRONTEND_PATH": ("path", str),
-            "LANGFLOW_OPEN_BROWSER": ("open_browser", lambda x: x.lower() == "true"),
-            "LANGFLOW_REMOVE_API_KEYS": ("remove_api_keys", lambda x: x.lower() == "true"),
-            "LANGFLOW_BACKEND_ONLY": ("backend_only", lambda x: x.lower() == "true"),
-            "LANGFLOW_STORE": ("store", lambda x: x.lower() == "true"),
-        }
-
-        # Update variables based on environment variables
-        for env_var, (var_name, var_type) in env_var_mapping.items():
-            if env_var in env_vars:
-                locals()[var_name] = var_type(env_vars[env_var])
 
     update_settings(
         dev=dev,

src/backend/base/langflow/services/settings/factory.py

@@ -3,6 +3,13 @@ from langflow.services.settings.service import SettingsService
 
 
 class SettingsServiceFactory(ServiceFactory):
+    _instance = None
+
+    def __new__(cls):
+        if cls._instance is None:
+            cls._instance = super().__new__(cls)
+        return cls._instance
+
     def __init__(self):
         super().__init__(SettingsService)