Struct FileCallbackHandler 

pub struct FileCallbackHandler { /* private fields */ }

A callback handler that writes run events to a log file.

Implementations

impl FileCallbackHandler

pub fn new(path: impl Into<PathBuf>) -> Result<Self, Error>

Creates a new handler that appends logs to the file at path.

pub fn with_format(self, format: LogFormat) -> Self

Sets the log output format.

Trait Implementations

impl CallbackHandler for FileCallbackHandler

fn on_run_start<'life0, 'life1, 'async_trait>( &'life0 self, run: &'life1 RunTree, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Called when any run starts

fn on_run_end<'life0, 'life1, 'async_trait>( &'life0 self, run: &'life1 RunTree, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Called when a run ends successfully

fn on_run_error<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, run: &'life1 RunTree, error: &'life2 str, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Called when a run fails

fn on_llm_start<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, run: &'life1 RunTree, messages: &'life2 [Message], ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Called when an LLM starts

fn on_llm_end<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, run: &'life1 RunTree, response: &'life2 str, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Called when an LLM ends

fn on_llm_new_token<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, run: &'life1 RunTree, token: &'life2 str, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Called for each new token during streaming

fn on_llm_error<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, run: &'life1 RunTree, error: &'life2 str, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Called when an LLM errors

fn on_chain_start<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, run: &'life1 RunTree, inputs: &'life2 Value, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Called when a chain starts

fn on_chain_end<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, run: &'life1 RunTree, outputs: &'life2 Value, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Called when a chain ends

fn on_chain_error<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, run: &'life1 RunTree, error: &'life2 str, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Called when a chain errors

fn on_tool_start<'life0, 'life1, 'life2, 'life3, 'async_trait>( &'life0 self, run: &'life1 RunTree, tool_name: &'life2 str, input: &'life3 str, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait, 'life3: 'async_trait,

Called when a tool starts

fn on_tool_end<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, run: &'life1 RunTree, output: &'life2 str, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Called when a tool ends

fn on_tool_error<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, run: &'life1 RunTree, error: &'life2 str, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Called when a tool errors

fn on_retriever_start<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, run: &'life1 RunTree, query: &'life2 str, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Called when a retriever starts

fn on_retriever_end<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, run: &'life1 RunTree, documents: &'life2 [Value], ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Called when a retriever ends

fn on_retriever_error<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, run: &'life1 RunTree, error: &'life2 str, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Called when a retriever errors

fn on_llm_thinking<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, _run: &'life1 RunTree, _thinking: &'life2 str, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Called for each thinking token during streaming (extended thinking).

impl Debug for FileCallbackHandler

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.