Invokes another graph (sub-flow) and optionally waits for its completion. The await activity enables compositional workflows where one graph triggers another by publishing to its subscribes topic, creating a parent-child relationship between flows.

The topic in the await activity must match the subscribes topic of the child graph. Both graphs are defined in the same app YAML:

app:
id: myapp
version: '1'
graphs:

# ── Parent graph ──────────────────────────────
- subscribes: order.placed
expire: 120

activities:
t1:
type: trigger
job:
maps:
orderId: '{$self.output.data.id}'

a1:
type: await
topic: approval.requested # ◄── targets the child graph's subscribes
await: true
input:
schema:
type: object
properties:
orderId: { type: string }
maps:
orderId: '{t1.output.data.id}'
output:
schema:
type: object
properties:
approved: { type: boolean }
job:
maps:
approval: '{$self.output.data.approved}'

done:
type: hook

transitions:
t1:
- to: a1
a1:
- to: done

# ── Child graph (invoked by the await) ────────
- subscribes: approval.requested # ◄── matched by the await activity's topic
publishes: approval.completed
expire: 60

activities:
t1:
type: trigger
review:
type: worker
topic: approval.review

transitions:
t1:
- to: review

When await is explicitly set to false, the activity starts the child flow but does not wait for its completion. The parent flow immediately continues. The child's job_id is returned as the output.

a1:
type: await
topic: background.process
await: false
job:
maps:
childJobId: '{$self.output.data.job_id}'

Await is a Category A (duplex) activity:

  • Leg 1 (process): Maps input data and publishes a StreamDataType.AWAIT message to the engine stream. The engine starts the child flow.
  • Leg 2 (processEvent, inherited): Receives the child flow's final output, maps output data, and transitions to adjacent activities.

AwaitActivity for the TypeScript interface

Hierarchy (view full)

Constructors

Properties

adjacencyList: StreamData[]
adjacentIndex: number = 0
code: number = 200
context: JobState
guidLedger: number = 0
logger: ILogger
status: StreamStatus = StreamStatus.SUCCESS

Methods