Enum StreamEvent 

pub enum StreamEvent<S: State> {
    Values {
        state: S,
        step: usize,
    },
    FilteredValues {
        data: Value,
        step: usize,
    },
    Updates {
        node: String,
        update: S::Update,
        step: usize,
    },
    FilteredUpdates {
        node: String,
        data: Value,
        step: usize,
    },
    Messages {
        chunk: MessageChunk,
        metadata: MessageStreamMetadata,
    },
    Custom {
        node: String,
        data: Value,
        ns: Vec<String>,
    },
    TaskStart {
        node: String,
        task_id: String,
        step: usize,
    },
    TaskEnd {
        node: String,
        task_id: String,
        step: usize,
        duration_ms: u64,
    },
    Interrupt {
        node: String,
        payload: Value,
        resumable: bool,
        ns: Vec<String>,
    },
    BudgetExceeded {
        reason: BudgetExceededReason,
        usage: BudgetUsage,
    },
    End {
        output: S,
    },
    Cancelled {
        step: usize,
    },
    Debug(DebugEvent),
    Tools(ToolsEvent),
    CheckpointSaved {
        checkpoint_id: String,
        metadata: CheckpointMetadata,
        step: usize,
    },
    TaskDetail {
        task_id: String,
        node: String,
        step: usize,
        attempt: usize,
        event: TaskEventType,
    },
}

Stream event during graph execution

Variants

Values

Complete state snapshot

Fields

state: S

step: usize

FilteredValues

Filtered state snapshot (only selected fields as JSON).

Emitted instead of Values when StreamConfig::output_keys is set. The data field contains a JSON object with only the keys requested by the caller.

Fields

data: Value

step: usize

Updates

Node update

Fields

node: String

update: S::Update

step: usize

FilteredUpdates

Filtered node update (only selected fields as JSON).

Emitted instead of Updates when StreamConfig::output_keys is set.

Fields

node: String

data: Value

step: usize

Messages

LLM token chunk

Fields

chunk: MessageChunk

metadata: MessageStreamMetadata

Custom

Custom event from node

Fields

node: String

data: Value

ns: Vec<String>

TaskStart

Task started

Fields

node: String

task_id: String

step: usize

TaskEnd

Task completed

Fields

node: String

task_id: String

step: usize

duration_ms: u64

Interrupt

HITL interrupt

Fields

node: String

payload: Value

resumable: bool

ns: Vec<String>

BudgetExceeded

Budget exceeded

Fields

reason: BudgetExceededReason

usage: BudgetUsage

End

Graph execution completed

Fields

output: S

Cancelled

Graph execution was cancelled (e.g. by the caller dropping the stream).

Emitted when the graph is interrupted before reaching a natural End. Consumers use this to distinguish between successful completion (End), cancellation (Cancelled), and errors (propagated via Result).

Fields

step: usize

Debug(DebugEvent)

Debug event

Tools(ToolsEvent)

Tool lifecycle event

CheckpointSaved

Checkpoint saved

Fields

checkpoint_id: String

metadata: CheckpointMetadata

step: usize

TaskDetail

Detailed task event

Fields

task_id: String

node: String

step: usize

attempt: usize

event: TaskEventType

Implementations

impl<S: State> StreamEvent<S>

pub fn namespace(&self) -> &[String]

Return the namespace segment list attached to this event, if any.

Events originating from subgraphs carry a non-empty ns field (the nesting path). Top-level graph events return an empty slice. This is used by stream filtering to decide whether to forward or suppress subgraph events.

Trait Implementations

impl<S: Clone + State> Clone for StreamEvent<S>

where S::Update: Clone,

fn clone(&self) -> StreamEvent<S>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<S: Debug + State> Debug for StreamEvent<S>

where S::Update: Debug,

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

Formats the value using the given formatter.