Trait ContextStore 

pub trait ContextStore: Send + Sync {
    // Required methods
    fn put(
        &self,
        flow_run_id: FlowRunId,
        node_id: NodeId,
        value: &Value,
    ) -> Result<(), ContextStoreError>;
    fn get(
        &self,
        flow_run_id: FlowRunId,
        node_id: NodeId,
    ) -> Result<Option<Value>, ContextStoreError>;
    fn list_keys(
        &self,
        flow_run_id: FlowRunId,
    ) -> Result<Vec<NodeId>, ContextStoreError>;
    fn put_global(
        &self,
        key: &str,
        value: &Value,
    ) -> Result<(), ContextStoreError>;
    fn upsert_global(
        &self,
        key: &str,
        value: &Value,
    ) -> Result<(), ContextStoreError>;
    fn get_global(&self, key: &str) -> Result<Option<Value>, ContextStoreError>;
}

Durable store for flow node outputs.

Keyed by (FlowRunId, NodeId) for node outputs and by String for globals. All methods are synchronous — the SQLite backend runs on a blocking thread, and callers (Step handlers in Sprint 4) will invoke from a blocking context or use spawn_blocking.

Required Methods

fn put( &self, flow_run_id: FlowRunId, node_id: NodeId, value: &Value, ) -> Result<(), ContextStoreError>

Write a node’s output. Enforces write-once semantics:

• First call for a given (flow_run_id, node_id): stores the value, returns Ok(())
• Subsequent calls with the same key: returns Err(ContextStoreError::AlreadyExists)

fn get( &self, flow_run_id: FlowRunId, node_id: NodeId, ) -> Result<Option<Value>, ContextStoreError>

Read a node’s output. Returns None if not yet written.

fn list_keys( &self, flow_run_id: FlowRunId, ) -> Result<Vec<NodeId>, ContextStoreError>

List all node IDs that have outputs for a given flow run.

fn put_global(&self, key: &str, value: &Value) -> Result<(), ContextStoreError>

Write a global key-value pair. Globals are not scoped to a flow run. Write-once semantics: second put for the same key returns GlobalAlreadyExists.

fn upsert_global( &self, key: &str, value: &Value, ) -> Result<(), ContextStoreError>

Write or update a global key-value pair. Unlike put_global, this allows overwriting an existing value. Used for mutable global metadata (e.g., coordinator map).

fn get_global(&self, key: &str) -> Result<Option<Value>, ContextStoreError>

Read a global value. Returns None if not yet written.

Implementors

impl ContextStore for SqliteContextStore