defineTask

Purpose and behavior

Declare a workflow node from its key, after dependencies and perform callback, with optional condition, retry, timeoutMs, cache, gate or interaction. It allocates no sandbox, and nothing runs until Workflow.start(). Throws on a key outside [A-Za-z0-9][A-Za-z0-9._-]*, invalid retry or cache settings, or a cache combined with a gate or interaction.

Complete example and detailed rules.

Parameters and properties

• optionsRequired
  TaskOptions<T>
  Task key, dependencies and perform callback, with optional condition, retry, timeout, cache, gate or interaction.
• options.retryOptional
  Retry | undefined
  Retry policy for failed attempts; without it the task runs once. A retried attempt repeats its side effects.
• options.cacheOptional
  TaskCacheOptions | undefined
  Result cache: a hit restores the stored lossless JSON value with no attempt, usage or side effects. On a miss, a result that is not lossless JSON fails the task. Rejected on gates, interactions and dispatch-result tasks.
• options.gateOptional
  WorkflowGate | undefined
  Persisted approval or pause definition; execution requires a checkpoint and a matching trusted decision.
• options.keyRequired
  string
  Unique key in the workflow, matching [A-Za-z0-9][A-Za-z0-9._-]*. Records, events and checkpoints identify the task by it.
• options.interactionOptional
  TaskInteraction | undefined
  Opt-in durable human-input contract; requires checkpointed scheduling and cannot be combined with a gate.
• options.performRequired
  (context: TaskContext) => T | Promise<T>
  Runs each attempt and returns the task output; with a checkpoint, the output must be lossless JSON or undefined. Stop work when context.signal aborts.
• options.conditionOptional
  ((context: TaskContext) => boolean | Promise<boolean>) | undefined
  Evaluated with attempt 0 before the task runs, including when a later start() resumes it; false ends the task as skipped, which skips its dependents.
• options.timeoutMsOptional
  number | undefined
  Deadline in milliseconds for each attempt, a positive integer up to 2147483647. Expiry aborts context.signal and fails the attempt, which retry may repeat.
• options.afterOptional
  readonly Task<unknown>[] | undefined
  Tasks that must be done before this one starts, default none; only these can be read with context.value().

Returns

Task<T>

Signature

export declare function defineTask<T>(options: TaskOptions<T>): Task<T>;

Related contracts

• Task
• TaskOptions