🔧 chore(__main__.py): change default value of cache option to None for better flexibility

🐛 fix(utils.py): handle ImportError when importing cache class and log a warning message
🔧 chore(settings.py): change default value of CACHE option to None for better flexibility

Fixes #880

src/backend/langflow/__main__.py

@@ -117,10 +117,10 @@ def serve(
     log_file: Path = typer.Option(
         "logs/langflow.log", help="Path to the log file.", envvar="LANGFLOW_LOG_FILE"
     ),
-    cache: str = typer.Option(
+    cache: Optional[str] = typer.Option(
         envvar="LANGFLOW_LANGCHAIN_CACHE",
         help="Type of cache to use. (InMemoryCache, SQLiteCache)",
-        default="SQLiteCache",
+        default=None,
     ),
     jcloud: bool = typer.Option(False, help="Deploy on Jina AI Cloud"),
     dev: bool = typer.Option(False, help="Run in development mode (may contain bugs)"),

src/backend/langflow/interface/utils.py

@@ -78,9 +78,14 @@ def set_langchain_cache(settings):
     import langchain
     from langflow.interface.importing.utils import import_class
 
-    cache_type = os.getenv("LANGFLOW_LANGCHAIN_CACHE")
-    cache_class = import_class(f"langchain.cache.{cache_type or settings.CACHE}")
+    if cache_type := os.getenv("LANGFLOW_LANGCHAIN_CACHE"):
+        try:
+            cache_class = import_class(
+                f"langchain.cache.{cache_type or settings.CACHE}"
+            )
 
-    logger.debug(f"Setting up LLM caching with {cache_class.__name__}")
-    langchain.llm_cache = cache_class()
-    logger.info(f"LLM caching setup with {cache_class.__name__}")
+            logger.debug(f"Setting up LLM caching with {cache_class.__name__}")
+            langchain.llm_cache = cache_class()
+            logger.info(f"LLM caching setup with {cache_class.__name__}")
+        except ImportError:
+            logger.warning(f"Could not import {cache_type}. ")

src/backend/langflow/settings.py

@@ -32,7 +32,7 @@ class Settings(BaseSettings):
 
     DEV: bool = False
     DATABASE_URL: Optional[str] = None
-    CACHE: str = "InMemoryCache"
+    CACHE: Optional[str] = None
     REMOVE_API_KEYS: bool = False
     COMPONENTS_PATH: List[str] = []