(fix) Langfuse key based logging (#6372)

* langfuse use helper for get_langfuse_logging_config

* fix get_langfuse_logger_for_request

* fix import

* fix get_langfuse_logger_for_request

* test_get_langfuse_logger_for_request_with_dynamic_params

* unit testing for test_get_langfuse_logger_for_request_with_no_dynamic_params

* parameterized langfuse testing

* fix langfuse test

* fix langfuse logging

* fix test_aaalangfuse_logging_metadata

* fix langfuse log metadata test

* fix langfuse logger

* use create_langfuse_logger_from_credentials

* fix test_get_langfuse_logger_for_request_with_no_dynamic_params

* fix correct langfuse/ folder structure

* use static methods for langfuse logger

* add commment on langfuse handler

* fix linting error

* add unit testing for langfuse logging

* fix linting

* fix failure handler langfuse

litellm/integrations/langfuse/langfuse_handler.py

@@ -0,0 +1,168 @@
+"""
+This file contains the LangFuseHandler class
+
+Used to get the LangFuseLogger for a given request
+
+Handles Key/Team Based Langfuse Logging
+"""
+
+from typing import TYPE_CHECKING, Any, Dict, Optional
+
+from litellm.litellm_core_utils.litellm_logging import StandardCallbackDynamicParams
+
+from .langfuse import LangFuseLogger, LangfuseLoggingConfig
+
+if TYPE_CHECKING:
+    from litellm.litellm_core_utils.litellm_logging import DynamicLoggingCache
+else:
+    DynamicLoggingCache = Any
+
+
+class LangFuseHandler:
+
+    @staticmethod
+    def get_langfuse_logger_for_request(
+        standard_callback_dynamic_params: StandardCallbackDynamicParams,
+        in_memory_dynamic_logger_cache: DynamicLoggingCache,
+        globalLangfuseLogger: Optional[LangFuseLogger] = None,
+    ) -> LangFuseLogger:
+        """
+        This function is used to get the LangFuseLogger for a given request
+
+        1. If dynamic credentials are passed
+            - check if a LangFuseLogger is cached for the dynamic credentials
+            - if cached LangFuseLogger is not found, create a new LangFuseLogger and cache it
+
+        2. If dynamic credentials are not passed return the globalLangfuseLogger
+
+        """
+        temp_langfuse_logger: Optional[LangFuseLogger] = globalLangfuseLogger
+        if (
+            LangFuseHandler._dynamic_langfuse_credentials_are_passed(
+                standard_callback_dynamic_params
+            )
+            is False
+        ):
+            return LangFuseHandler._return_global_langfuse_logger(
+                globalLangfuseLogger=globalLangfuseLogger,
+                in_memory_dynamic_logger_cache=in_memory_dynamic_logger_cache,
+            )
+
+        # get langfuse logging config to use for this request, based on standard_callback_dynamic_params
+        _credentials = LangFuseHandler.get_dynamic_langfuse_logging_config(
+            globalLangfuseLogger=globalLangfuseLogger,
+            standard_callback_dynamic_params=standard_callback_dynamic_params,
+        )
+        credentials_dict = dict(_credentials)
+
+        # check if langfuse logger is already cached
+        temp_langfuse_logger = in_memory_dynamic_logger_cache.get_cache(
+            credentials=credentials_dict, service_name="langfuse"
+        )
+
+        # if not cached, create a new langfuse logger and cache it
+        if temp_langfuse_logger is None:
+            temp_langfuse_logger = (
+                LangFuseHandler._create_langfuse_logger_from_credentials(
+                    credentials=credentials_dict,
+                    in_memory_dynamic_logger_cache=in_memory_dynamic_logger_cache,
+                )
+            )
+
+        return temp_langfuse_logger
+
+    @staticmethod
+    def _return_global_langfuse_logger(
+        globalLangfuseLogger: Optional[LangFuseLogger],
+        in_memory_dynamic_logger_cache: DynamicLoggingCache,
+    ) -> LangFuseLogger:
+        """
+        Returns the Global LangfuseLogger set on litellm
+
+        (this is the default langfuse logger - used when no dynamic credentials are passed)
+
+        If no Global LangfuseLogger is set, it will check in_memory_dynamic_logger_cache for a cached LangFuseLogger
+        This function is used to return the globalLangfuseLogger if it exists, otherwise it will check in_memory_dynamic_logger_cache for a cached LangFuseLogger
+        """
+        if globalLangfuseLogger is not None:
+            return globalLangfuseLogger
+
+        credentials_dict: Dict[str, Any] = (
+            {}
+        )  # the global langfuse logger uses Environment Variables, there are no dynamic credentials
+        globalLangfuseLogger = in_memory_dynamic_logger_cache.get_cache(
+            credentials=credentials_dict,
+            service_name="langfuse",
+        )
+        if globalLangfuseLogger is None:
+            globalLangfuseLogger = (
+                LangFuseHandler._create_langfuse_logger_from_credentials(
+                    credentials=credentials_dict,
+                    in_memory_dynamic_logger_cache=in_memory_dynamic_logger_cache,
+                )
+            )
+        return globalLangfuseLogger
+
+    @staticmethod
+    def _create_langfuse_logger_from_credentials(
+        credentials: Dict,
+        in_memory_dynamic_logger_cache: DynamicLoggingCache,
+    ) -> LangFuseLogger:
+        """
+        This function is used to
+        1. create a LangFuseLogger from the credentials
+        2. cache the LangFuseLogger to prevent re-creating it for the same credentials
+        """
+
+        langfuse_logger = LangFuseLogger(
+            langfuse_public_key=credentials.get("langfuse_public_key"),
+            langfuse_secret=credentials.get("langfuse_secret"),
+            langfuse_host=credentials.get("langfuse_host"),
+        )
+        in_memory_dynamic_logger_cache.set_cache(
+            credentials=credentials,
+            service_name="langfuse",
+            logging_obj=langfuse_logger,
+        )
+        return langfuse_logger
+
+    @staticmethod
+    def get_dynamic_langfuse_logging_config(
+        standard_callback_dynamic_params: StandardCallbackDynamicParams,
+        globalLangfuseLogger: Optional[LangFuseLogger] = None,
+    ) -> LangfuseLoggingConfig:
+        """
+        This function is used to get the Langfuse logging config to use for a given request.
+
+        It checks if the dynamic parameters are provided in the standard_callback_dynamic_params and uses them to get the Langfuse logging config.
+
+        If no dynamic parameters are provided, it uses the `globalLangfuseLogger` values
+        """
+        # only use dynamic params if langfuse credentials are passed dynamically
+        return LangfuseLoggingConfig(
+            langfuse_secret=standard_callback_dynamic_params.get("langfuse_secret")
+            or standard_callback_dynamic_params.get("langfuse_secret_key"),
+            langfuse_public_key=standard_callback_dynamic_params.get(
+                "langfuse_public_key"
+            ),
+            langfuse_host=standard_callback_dynamic_params.get("langfuse_host"),
+        )
+
+    @staticmethod
+    def _dynamic_langfuse_credentials_are_passed(
+        standard_callback_dynamic_params: StandardCallbackDynamicParams,
+    ) -> bool:
+        """
+        This function is used to check if the dynamic langfuse credentials are passed in standard_callback_dynamic_params
+
+        Returns:
+            bool: True if the dynamic langfuse credentials are passed, False otherwise
+        """
+        if (
+            standard_callback_dynamic_params.get("langfuse_host") is not None
+            or standard_callback_dynamic_params.get("langfuse_public_key") is not None
+            or standard_callback_dynamic_params.get("langfuse_secret") is not None
+            or standard_callback_dynamic_params.get("langfuse_secret_key") is not None
+        ):
+            return True
+        return False