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Checkpointer

lc_langgraph::checkpointer

Trait Checkpointer 

Source 
pub trait Checkpointer<S: StateSchema>: Send + Sync {
    // Required methods
    fn save<'life0, 'life1, 'async_trait>(
        &'life0 self,
        state: &'life1 S,
        recursion_count: usize,
    ) -> Pin<Box<dyn Future<Output = GraphResult<String>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait,
             'life1: 'async_trait;
    fn load<'life0, 'life1, 'async_trait>(
        &'life0 self,
        checkpoint_id: &'life1 str,
    ) -> Pin<Box<dyn Future<Output = GraphResult<S>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait,
             'life1: 'async_trait;
    fn list<'life0, 'async_trait>(
        &'life0 self,
    ) -> Pin<Box<dyn Future<Output = GraphResult<Vec<String>>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait;
    fn delete<'life0, 'life1, 'async_trait>(
        &'life0 self,
        checkpoint_id: &'life1 str,
    ) -> Pin<Box<dyn Future<Output = GraphResult<()>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait,
             'life1: 'async_trait;
    fn last<'life0, 'async_trait>(
        &'life0 self,
    ) -> Pin<Box<dyn Future<Output = GraphResult<Option<(S, usize)>>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait;

    // Provided methods
    fn snapshots<'life0, 'async_trait>(
        &'life0 self,
    ) -> Pin<Box<dyn Future<Output = GraphResult<Vec<CheckpointInfo<S>>>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait { ... }
    fn update_state<'life0, 'life1, 'life2, 'async_trait>(
        &'life0 self,
        checkpoint_id: &'life1 str,
        state: &'life2 S,
        expected_version: u64,
    ) -> Pin<Box<dyn Future<Output = GraphResult<u64>> + Send + 'async_trait>>
       where Self: 'async_trait,
             'life0: 'async_trait,
             'life1: 'async_trait,
             'life2: 'async_trait { ... }
}
Expand description

Checkpointer trait for state persistence

Required Methods§

Source

fn save<'life0, 'life1, 'async_trait>( &'life0 self, state: &'life1 S, recursion_count: usize, ) -> Pin<Box<dyn Future<Output = GraphResult<String>> + Send + 'async_trait>>
where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Insert a new checkpoint, recording how much of the recursion budget had been consumed by the run at that point (M6).

Source

fn load<'life0, 'life1, 'async_trait>( &'life0 self, checkpoint_id: &'life1 str, ) -> Pin<Box<dyn Future<Output = GraphResult<S>> + Send + 'async_trait>>
where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Load the state saved under the given checkpoint id.

Source

fn list<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = GraphResult<Vec<String>>> + Send + 'async_trait>>
where Self: 'async_trait, 'life0: 'async_trait,

List checkpoint ids, ordered from oldest to most recent (H5).

Source

fn delete<'life0, 'life1, 'async_trait>( &'life0 self, checkpoint_id: &'life1 str, ) -> Pin<Box<dyn Future<Output = GraphResult<()>> + Send + 'async_trait>>
where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Delete the checkpoint with the given id.

Source

fn last<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = GraphResult<Option<(S, usize)>>> + Send + 'async_trait>>
where Self: 'async_trait, 'life0: 'async_trait,

State and recursion budget of the most recently saved checkpoint.

Provided Methods§

Source

fn snapshots<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = GraphResult<Vec<CheckpointInfo<S>>>> + Send + 'async_trait>>
where Self: 'async_trait, 'life0: 'async_trait,

List every checkpoint as a full snapshot (state + ordering keys + recursion budget), oldest first.

Used by CompiledGraph::get_state_history and time-travel forks. The default reconstructs a state-only history from list + load and reports an unknown timestamp/seq/recursion_count of 0; backends that store the full CheckpointData (or its columns) override this to report the real ordering keys and budget.

Source

fn update_state<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, checkpoint_id: &'life1 str, state: &'life2 S, expected_version: u64, ) -> Pin<Box<dyn Future<Output = GraphResult<u64>> + Send + 'async_trait>>
where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Replace the state stored in an existing checkpoint (the LangGraph updateState analogue), using optimistic concurrency control.

expected_version is the version of the state the edit is based on (every fresh checkpoint starts at version 1, and each successful update_state bumps it). When the stored version has moved on because another writer edited the checkpoint first, the call fails with GraphError::CheckpointVersionConflict instead of overwriting that edit. Returns the new version.

Backends without edit support keep the default implementation, which fails with GraphError::CheckpointError.

Dyn Compatibility§

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors§