g3fih)dZddlmZddlZddlZddlmZddlmZddl m Z m Z m Z m Z mZddlmZmZerddlmZmZdd lmZGd d eZy) z"Model retry middleware for agents.) annotationsN) TYPE_CHECKING) AIMessage) OnFailureRetryOncalculate_delayshould_retry_exceptionvalidate_retry_params)AgentMiddleware ModelResponse) AwaitableCallable) ModelRequestceZdZdZdefdddddd dfd Zdd Zdd Z dd Z dd Z xZ S)ModelRetryMiddlewarea Middleware that automatically retries failed model calls with configurable backoff. Supports retrying on specific exceptions and exponential backoff. Examples: !!! example "Basic usage with default settings (2 retries, exponential backoff)" ```python from langchain.agents import create_agent from langchain.agents.middleware import ModelRetryMiddleware agent = create_agent(model, tools=[search_tool], middleware=[ModelRetryMiddleware()]) ``` !!! example "Retry specific exceptions only" ```python from anthropic import RateLimitError from openai import APITimeoutError retry = ModelRetryMiddleware( max_retries=4, retry_on=(APITimeoutError, RateLimitError), backoff_factor=1.5, ) ``` !!! example "Custom exception filtering" ```python from anthropic import APIStatusError def should_retry(exc: Exception) -> bool: # Only retry on 5xx errors if isinstance(exc, APIStatusError): return 500 <= exc.status_code < 600 return False retry = ModelRetryMiddleware( max_retries=3, retry_on=should_retry, ) ``` !!! example "Custom error handling" ```python def format_error(exc: Exception) -> str: return "Model temporarily unavailable. Please try again later." retry = ModelRetryMiddleware( max_retries=4, on_failure=format_error, ) ``` !!! example "Constant backoff (no exponential growth)" ```python retry = ModelRetryMiddleware( max_retries=5, backoff_factor=0.0, # No exponential growth initial_delay=2.0, # Always wait 2 seconds ) ``` !!! example "Raise exception on failure" ```python retry = ModelRetryMiddleware( max_retries=2, on_failure="error", # Re-raise exception instead of returning message ) ``` continueg@g?gN@T) max_retriesretry_on on_failurebackoff_factor initial_delay max_delayjitterct|t||||||_g|_||_||_||_||_||_ ||_ y)uInitialize `ModelRetryMiddleware`. Args: max_retries: Maximum number of retry attempts after the initial call. Must be `>= 0`. retry_on: Either a tuple of exception types to retry on, or a callable that takes an exception and returns `True` if it should be retried. Default is to retry on all exceptions. on_failure: Behavior when all retries are exhausted. Options: - `'continue'`: Return an `AIMessage` with error details, allowing the agent to continue with an error response. - `'error'`: Re-raise the exception, stopping agent execution. - **Custom callable:** Function that takes the exception and returns a string for the `AIMessage` content, allowing custom error formatting. backoff_factor: Multiplier for exponential backoff. Each retry waits `initial_delay * (backoff_factor ** retry_number)` seconds. Set to `0.0` for constant delay. initial_delay: Initial delay in seconds before first retry. max_delay: Maximum delay in seconds between retries. Caps exponential backoff growth. jitter: Whether to add random jitter (`±25%`) to delay to avoid thundering herd. Raises: ValueError: If `max_retries < 0` or delays are negative. N) super__init__r rtoolsrrrrrr) selfrrrrrrr __class__s e/var/www/auto_recruiter/arenv/lib/python3.12/site-packages/langchain/agents/middleware/model_retry.pyrzModelRetryMiddleware.__init__js\\  k=)^T&   $,*" ct|j}t|}|dk(rdnd}d|d|d|d|}t|S) a Format the failure message when retries are exhausted. Args: exc: The exception that caused the failure. attempts_made: Number of attempts actually made. Returns: `AIMessage` with formatted error message. attemptattemptszModel call failed after  z with z: content)type__name__strr)rexc attempts_madeexc_typeexc_msg attempt_wordr)s r!_format_failure_messagez,ModelRetryMiddleware._format_failure_messages[9%%c($1Q$6yJ &}oQ|nF8*TVW^V_ ` ))r"c|jdk(r|t|jr|j|}t|}n|j||}t |gS)a\Handle failure when all retries are exhausted. Args: exc: The exception that caused the failure. attempts_made: Number of attempts actually made. Returns: `ModelResponse` with error details. Raises: Exception: If `on_failure` is `'error'`, re-raises the exception. errorr()result)rcallablerr2r )rr-r.r)ai_msgs r!_handle_failurez$ModelRetryMiddleware._handle_failuresX ??g %I DOO $ooc*Gw/F11#}EFVH--r"c t|jdzD] } ||cSd}t|#t$r}|dz}t||js|j ||cYd}~cS||jkrSt ||j|j|j|j}|dkDr/tj|n|j ||cYd}~cSYd}~d}~wwxYw)a8Intercept model execution and retry on failure. Args: request: Model request with model, messages, state, and runtime. handler: Callable to execute the model (can be called multiple times). Returns: `ModelResponse` or `AIMessage` (the final result). r$Nrrrrr2Unexpected: retry loop completed without returning)ranger Exceptionr rr8rrrrrtimesleep RuntimeErrorrrequesthandlerr%r-r.delaymsgs r!wrap_model_callz$ModelRetryMiddleware.wrap_model_callsT--12 DG Dw'' D:C37 D '! .c4==A//]CCT---+'+':':&*&8&8"&..#{{ Eqy 5) //]CC/ Ds'5 C7,C2*C72A3C2%C72C7c "Kt|jdzD]} ||d{cSd}t|7#t$r}|dz}t||js|j ||cYd}~cS||jkr\t ||j|j|j|j}|dkDr8tj|d{7n|j ||cYd}~cSYd}~d}~wwxYww)aIIntercept and control async model execution with retry logic. Args: request: Model request with model, messages, state, and runtime. handler: Async callable to execute the model and returns `ModelResponse`. Returns: `ModelResponse` or `AIMessage` (the final result). r$Nr:rr;)r<rr=r rr8rrrrrasyncior?r@rAs r!awrap_model_callz%ModelRetryMiddleware.awrap_model_callsT--12 DG D$W--- D:C39. D '! .c4==A//]CCT---+'+':':&*&8&8"&..#{{ Eqy%mmE222 //]CC/ Ds`D A?ADA D  ,D6D 7D>A$D"C%#D:D ; DD  D)rintrrrrrfloatrrKrrKrboolreturnNone)r-r=r.rJrMr)r-r=r.rJrMr )rBrrCz'Callable[[ModelRequest], ModelResponse]rMModelResponse | AIMessage)rBrrCz2Callable[[ModelRequest], Awaitable[ModelResponse]]rMrO) r+ __module__ __qualname____doc__r=rr2r8rFrI __classcell__)r s@r!rrsMd&L * #":: :  :  :::: :x*$.0- - 9-  # - ^- - D-  # - r"r)rR __future__rrHr>typingrlangchain_core.messagesr"langchain.agents.middleware._retryrrrr r !langchain.agents.middleware.typesr r collections.abcr rrrr"r!r[s>(" -M3>R ?R r"