Class Cycle

Re-executes an ancestor activity in a new dimensional thread, enabling retry loops and iterative patterns without violating the DAG constraint. The cycle activity targets a specific ancestor (typically a Hook with cycle: true) and sends execution back to that point.

Each cycle iteration runs in a fresh dimensional thread — individual activity state is isolated per iteration, while shared job state (job.maps) accumulates across iterations. This pattern enables retries, polling loops, and iterative processing.

YAML Configuration

app:
  id: myapp
  version: '1'
  graphs:
    - subscribes: retry.start
      expire: 300

      activities:
        t1:
          type: trigger

        pivot:
          type: hook
          cycle: true                    # marks this activity as a cycle target
          output:
            maps:
              retryCount: 0

        do_work:
          type: worker
          topic: work.do
          output:
            schema:
              type: object
              properties:
                result: { type: string }

        retry:
          type: cycle
          ancestor: pivot                # re-execute from this activity
          input:
            maps:
              retryCount:                # increment retry counter each cycle
                '@pipe':
                  - ['{pivot.output.data.retryCount}', 1]
                  - ['{@math.add}']

        done:
          type: hook

      transitions:
        t1:
          - to: pivot
        pivot:
          - to: do_work
        do_work:
          - to: retry
            conditions:
              code: 500                  # cycle on error
          - to: done

Key Behaviors

The ancestor field must reference an activity with cycle: true.
The cycle activity's input.maps override the ancestor's output data for the next iteration, allowing each cycle to pass different values.
Dimensional isolation ensures parallel cycle iterations don't collide.

Execution Model

Cycle is a Category A (Leg 1 only) activity:

Maps input data, resolves the re-entry dimensional address, and publishes a stream message addressed to the ancestor activity.
The ancestor re-enters via its Leg 2 path in the new dimension.

See

CycleActivity for the TypeScript interface

Hierarchy (view full)

Activity
- Cycle

Index

Constructors

constructor

Properties

adjacencyList adjacentIndex code config context data engine guidLedger hook leg logger metadata status

Constructors

constructor

new Cycle(config, data, metadata, hook, engine, context?): Cycle
Parameters
- config: ActivityType
- data: ActivityData
- metadata: ActivityMetadata
- hook: ActivityData
- engine: EngineService
- Optionalcontext: JobState
Returns Cycle
Inherited from Activity.constructor
- Defined in services/activities/activity/index.ts:86

Properties

adjacencyList

adjacencyList: StreamData[]

adjacentIndex

adjacentIndex: number = 0

code

code: number = 200

config

config: CycleActivity

context

context: JobState

data

data: ActivityData

engine

engine: EngineService

guidLedger

guidLedger: number = 0

hook

hook: ActivityData

leg

leg: ActivityLeg

logger

logger: ILogger

metadata

metadata: ActivityMetadata

status

status: StreamStatus = StreamStatus.SUCCESS

Methods

assertGenerationalId

assertGenerationalId(jobGID, msgGID?): void
Reject stale messages from a prior job generation
Parameters
- jobGID: string
- OptionalmsgGID: string
Returns void
Inherited from Activity.assertGenerationalId
- Defined in services/activities/activity/index.ts:155

authorizeEntry

authorizeEntry(_state): string[]
Parameters
- _state: StringAnyType
Returns string[]
Inherited from Activity.authorizeEntry
- Defined in services/activities/activity/index.ts:340

bindActivityData

bindActivityData(type): void
Attach inbound data (output or hook) to the activity's context slot
Parameters
- type: "hook" | "output"
Returns void
Inherited from Activity.bindActivityData
- Defined in services/activities/activity/index.ts:219

bindActivityError

bindActivityError(data): void
Attach an error response to the activity's context slot
Parameters
- data: Record<string, unknown>
Returns void
Inherited from Activity.bindActivityError
- Defined in services/activities/activity/index.ts:224

bindActivityMetadata

bindActivityMetadata(): void
Stamp activity-level timestamps, type, and subtype

Returns void
Inherited from Activity.bindActivityMetadata
- Defined in services/activities/activity/index.ts:199

bindActivityMetadataPaths

bindActivityMetadataPaths(): string[]
Activity metadata paths to persist (Trigger overrides; leg-aware)

Returns string[]
Inherited from Activity.bindActivityMetadataPaths
- Defined in services/activities/activity/index.ts:350

bindActivityState

bindActivityState(state): void
Flatten activity-level context paths into store-ready key/values
Parameters
- state: StringAnyType
Returns void
Inherited from Activity.bindActivityState
- Defined in services/activities/activity/index.ts:209

bindDimensionalAddress

bindDimensionalAddress(state): void
Write the dimensional address into the state payload
Parameters
- state: StringAnyType
Returns void
Inherited from Activity.bindDimensionalAddress
- Defined in services/activities/activity/index.ts:214

bindJobError

bindJobError(data): void
Promote an unhandled activity error to the job level
Parameters
- data: Record<string, unknown>
Returns void
Inherited from Activity.bindJobError
- Defined in services/activities/activity/index.ts:229

bindJobMetadata

bindJobMetadata(): void
Stamp job-level ju (job_updated) timestamp

Returns void
Inherited from Activity.bindJobMetadata
- Defined in services/activities/activity/index.ts:194

bindJobMetadataPaths

bindJobMetadataPaths(): string[]
Job metadata paths to persist (Trigger overrides with full JOB set)

Returns string[]
Inherited from Activity.bindJobMetadataPaths
- Defined in services/activities/activity/index.ts:345

bindJobState

bindJobState(state): Promise<void>
Flatten job-level context paths into store-ready key/values
Parameters
- state: StringAnyType
Returns Promise<void>
Inherited from Activity.bindJobState
- Defined in services/activities/activity/index.ts:204

bindMarkerData

bindMarkerData(_options?): void
Parameters
- Optional_options: any
Returns void
Inherited from Activity.bindMarkerData
- Defined in services/activities/activity/index.ts:342

bindSearchData

bindSearchData(_options?): void
Parameters
- Optional_options: any
Returns void
Inherited from Activity.bindSearchData
- Defined in services/activities/activity/index.ts:341

cycleAncestorActivity

cycleAncestorActivity(transaction): Promise<string>
Parameters
- transaction: ProviderTransaction
Returns Promise<string>
- Defined in services/activities/cycle.ts:144

executeLeg1StepProtocol

executeLeg1StepProtocol(delta): Promise<boolean>
Leg 1 protocol: save → spawn → complete (Category B activities)
Parameters
- delta: number
Returns Promise<boolean>
Inherited from Activity.executeLeg1StepProtocol
- Defined in services/activities/activity/index.ts:314

executeStepProtocol

executeStepProtocol(delta, shouldFinalize): Promise<boolean>
Leg 2 protocol: save → spawn → complete (duplex activities)
Parameters
- delta: number
- shouldFinalize: boolean
Returns Promise<boolean>
Inherited from Activity.executeStepProtocol
- Defined in services/activities/activity/index.ts:309

filterAdjacent

filterAdjacent(): Promise<StreamData[]>
Build the list of child activities to transition to

Returns Promise<StreamData[]>
Inherited from Activity.filterAdjacent
- Defined in services/activities/activity/index.ts:258

getJobStatus

getJobStatus(): number
Returns number
Inherited from Activity.getJobStatus
- Defined in services/activities/activity/index.ts:339

getState

getState(): Promise<void>
Load job state from the store into this.context

Returns Promise<void>
Inherited from Activity.getState
- Defined in services/activities/activity/index.ts:135

getTriggerConfig

getTriggerConfig(): Promise<ActivityType>
Returns Promise<ActivityType>
Inherited from Activity.getTriggerConfig
- Defined in services/activities/activity/index.ts:354

handleProcessError

handleProcessError(error, telemetry, label): void
Parameters
- error: Error
- telemetry: TelemetryService
- label: string
Returns void
Inherited from Activity.handleProcessError
- Defined in services/activities/activity/index.ts:367

initDimensionalAddress

initDimensionalAddress(dad): void
Set the dimensional address for this activity
Parameters
- dad: string
Returns void
Inherited from Activity.initDimensionalAddress
- Defined in services/activities/activity/index.ts:150

initPolicies

initPolicies(ctx): void
Resolve expire and persistent policies from config
Parameters
- ctx: JobState
Returns void
Inherited from Activity.initPolicies
- Defined in services/activities/activity/index.ts:145

initSelf

initSelf(ctx): JobState
Bootstrap $self, $job refs and output.metadata.au timestamp
Parameters
- ctx: StringAnyType
Returns JobState
Inherited from Activity.initSelf
- Defined in services/activities/activity/index.ts:140

isJobComplete

isJobComplete(s): boolean
Parameters
- s: number
Returns boolean
Inherited from Activity.isJobComplete
- Defined in services/activities/activity/index.ts:292

jobWasInterrupted

jobWasInterrupted(s): boolean
Parameters
- s: number
Returns boolean
Inherited from Activity.jobWasInterrupted
- Defined in services/activities/activity/index.ts:296

mapInputData

mapInputData(): void
Map data INTO this activity (from other activities' outputs)

Returns void
Inherited from Activity.mapInputData
- Defined in services/activities/activity/index.ts:167

mapJobData

mapJobData(): void
Promote activity data to the shared job state via job.maps

Returns void
Inherited from Activity.mapJobData
- Defined in services/activities/activity/index.ts:177

mapOutputData

mapOutputData(): void
Transform this activity's own output via output.maps

Returns void
Inherited from Activity.mapOutputData
- Defined in services/activities/activity/index.ts:172

mapStatusThreshold

mapStatusThreshold(): number
Resolve the Dynamic Activation Control threshold (default: 0)

Returns number
Inherited from Activity.mapStatusThreshold
- Defined in services/activities/activity/index.ts:182

process

process(): Promise<string>
Returns Promise<string>
- Defined in services/activities/cycle.ts:98

processEvent

processEvent(status?, code?, type?): Promise<void>
Parameters
- status: StreamStatus = StreamStatus.SUCCESS
- code: number = 200
- type: "hook" | "output" = 'output'
Returns Promise<void>
Inherited from Activity.processEvent
- Defined in services/activities/activity/index.ts:325

registerTimeout

registerTimeout(): Promise<void>
Returns Promise<void>
Inherited from Activity.registerTimeout
- Defined in services/activities/activity/index.ts:338

resolveAdjacentDad

resolveAdjacentDad(): string
Dimensional address for children (appends seed ,0)

Returns string
Inherited from Activity.resolveAdjacentDad
- Defined in services/activities/activity/index.ts:268

resolveDad

resolveDad(): string
Current dimensional address (accounts for cycle offset)

Returns string
Inherited from Activity.resolveDad
- Defined in services/activities/activity/index.ts:263

resolveStatus

resolveStatus(multi): number
Extract the job status from the last transaction result
Parameters
- multi: TransactionResultList
Returns number
Inherited from Activity.resolveStatus
- Defined in services/activities/activity/index.ts:278

resolveThresholdHit

resolveThresholdHit(results): boolean
Did the semaphore reach its threshold? (from transaction results)
Parameters
- results: TransactionResultList
Returns boolean
Inherited from Activity.resolveThresholdHit
- Defined in services/activities/activity/index.ts:273

setLeg

setLeg(leg): void
Parameters
- leg: ActivityLeg
Returns void
Inherited from Activity.setLeg
- Defined in services/activities/activity/index.ts:337

setState

setState(txn?): Promise<string>
Persist the full activity + job state in a single store call
Parameters
- Optionaltxn: ProviderTransaction
Returns Promise<string>
Inherited from Activity.setState
- Defined in services/activities/activity/index.ts:241

setStatus

setStatus(amount, txn?): Promise<any>
Increment/decrement the job semaphore
Parameters
- amount: number
- Optionaltxn: ProviderTransaction
Returns Promise<any>
Inherited from Activity.setStatus
- Defined in services/activities/activity/index.ts:246

shouldEmit

shouldEmit(): boolean
Should this activity emit to the graph's publishes topic?

Returns boolean
Inherited from Activity.shouldEmit
- Defined in services/activities/activity/index.ts:283

shouldPersistJob

shouldPersistJob(): boolean
Should this activity emit completion while keeping the job alive?

Returns boolean
Inherited from Activity.shouldPersistJob
- Defined in services/activities/activity/index.ts:288

verifyEntry

verifyEntry(): Promise<void>
Leg 1 entry for duplex activities (Worker, Await, Cycle)

Returns Promise<void>
Inherited from Activity.verifyEntry
- Defined in services/activities/activity/index.ts:112

verifyLeg1Entry

verifyLeg1Entry(): Promise<boolean>
Leg 1 entry for Category B (Hook passthrough, Signal, Interrupt-target). Returns true when resuming from a prior crash (Leg1 already committed).

Returns Promise<boolean>
Inherited from Activity.verifyLeg1Entry
- Defined in services/activities/activity/index.ts:123

verifyReentry

verifyReentry(): Promise<number>
Leg 2 re-entry for duplex activities; returns the activity ledger

Returns Promise<number>
Inherited from Activity.verifyReentry
- Defined in services/activities/activity/index.ts:117

Class Cycle

YAML Configuration

Key Behaviors

Execution Model

See

Hierarchy (view full)

Index

Constructors

Properties

Methods

Constructors

constructor

Parameters

Returns Cycle

Properties

adjacencyList

adjacentIndex

code

config

context

data

engine

guidLedger

hook

leg

logger

metadata

status

Methods

assertGenerationalId

Parameters

Returns void

authorizeEntry

Parameters

Returns string[]

bindActivityData

Parameters

Returns void

bindActivityError

Parameters

Returns void

bindActivityMetadata

Returns void

bindActivityMetadataPaths

Returns string[]

bindActivityState

Parameters

Returns void

bindDimensionalAddress

Parameters

Returns void

bindJobError

Parameters

Returns void

bindJobMetadata

Returns void

bindJobMetadataPaths

Returns string[]

bindJobState

Parameters

Returns Promise<void>

bindMarkerData

Parameters

Returns void

bindSearchData

Parameters

Returns void

cycleAncestorActivity

Parameters

Returns Promise<string>

executeLeg1StepProtocol

Parameters

Returns Promise<boolean>

executeStepProtocol

Parameters

Returns Promise<boolean>

filterAdjacent

Returns Promise<StreamData[]>

getJobStatus

Returns number