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Namespace: workflow

This library provides tools required for authoring workflows.

Usage​

See the tutorial for writing your first workflow.

Timers​

The recommended way of scheduling timers is by using the sleep function. We've replaced setTimeout and clearTimeout with deterministic versions so these are also usable but have a limitation that they don't play well with cancellation scopes.

import { sleep } from '@temporalio/workflow';

export async function sleeper(ms = 100): Promise<void> {
  await sleep(ms);
  console.log('slept');
}

Activities​

To schedule Activities, use proxyActivities to obtain an Activity function and call.

Signals and Queries​

To add signal handlers to a Workflow, add a signals property to the exported workflow object. Signal handlers can return either void or Promise<void>, you may schedule activities and timers from a signal handler.

To add query handlers to a Workflow, add a queries property to the exported workflow object. Query handlers must not mutate any variables or generate any commands (like Activities or Timers), they run synchronously and thus must return a Promise.

Implementation​

import { CancelledFailure, defineQuery, setHandler, condition } from '@temporalio/workflow';
import { unblockSignal } from './definitions';

export const isBlockedQuery = defineQuery<boolean>('isBlocked');

export async function unblockOrCancel(): Promise<void> {
  let isBlocked = true;
  setHandler(unblockSignal, () => void (isBlocked = false));
  setHandler(isBlockedQuery, () => isBlocked);
  try {
    console.log('Blocked');
    await condition(() => !isBlocked);
    isBlocked = false;
    console.log('Unblocked');
  } catch (err) {
    if (!(err instanceof CancelledFailure)) {
      throw err;
    }
    console.log('Cancelled');
  }
}

More​

Enumerations​

Classes​

Interfaces​

References​

ActivityCancellationType​

Re-exports ActivityCancellationType

ActivityFailure​

Re-exports ActivityFailure

ActivityFunction​

Re-exports ActivityFunction

ActivityInterface​

Re-exports ActivityInterface

ActivityOptions​

Re-exports ActivityOptions

ApplicationFailure​

Re-exports ApplicationFailure

CancelledFailure​

Re-exports CancelledFailure

ChildWorkflowFailure​

Re-exports ChildWorkflowFailure

Headers​

Re-exports Headers

LoggerSinks​

Re-exports LoggerSinks

Next​

Re-exports Next

Payload​

Re-exports Payload

PayloadConverter​

Re-exports PayloadConverter

QueryDefinition​

Re-exports QueryDefinition

RetryPolicy​

Re-exports RetryPolicy

SearchAttributeValue​

Re-exports SearchAttributeValue

SearchAttributes​

Re-exports SearchAttributes

ServerFailure​

Re-exports ServerFailure

SignalDefinition​

Re-exports SignalDefinition

TemporalFailure​

Re-exports TemporalFailure

TerminatedFailure​

Re-exports TerminatedFailure

TimeoutFailure​

Re-exports TimeoutFailure

UntypedActivities​

Re-exports UntypedActivities

Workflow​

Re-exports Workflow

WorkflowQueryType​

Re-exports WorkflowQueryType

WorkflowResultType​

Re-exports WorkflowResultType

WorkflowReturnType​

Re-exports WorkflowReturnType

WorkflowSignalType​

Re-exports WorkflowSignalType

defaultPayloadConverter​

Re-exports defaultPayloadConverter

rootCause​

Re-exports rootCause

Type Aliases​

ActivityInterfaceFor​

Ƭ ActivityInterfaceFor<T>: { [K in keyof T]: T[K] extends ActivityFunction ? T[K] : typeof NotAnActivityMethod }

Type helper that takes a type T and transforms attributes that are not ActivityFunction to NotAnActivityMethod.

Example

Used by proxyActivities to get this compile-time error:

interface MyActivities {
  valid(input: number): Promise<number>;
  invalid(input: number): number;
}

const act = proxyActivities<MyActivities>({ startToCloseTimeout: '5m' });

await act.valid(true);
await act.invalid();
// ^ TS complains with:
// (property) invalidDefinition: typeof NotAnActivityMethod
// This expression is not callable.
// Type 'Symbol' has no call signatures.(2349)

Type parameters​

Name
T

CommonWorkflowOptions​

Ƭ CommonWorkflowOptions: BaseWorkflowOptions & WorkflowDurationOptions

ConcludeActivationOutput​

Ƭ ConcludeActivationOutput: ConcludeActivationInput

Output for WorkflowInternalsInterceptor.concludeActivation

ContinueAsNewInputOptions​

Ƭ ContinueAsNewInputOptions: ContinueAsNewOptions & Required<Pick<ContinueAsNewOptions, "workflowType">>

Same as ContinueAsNewOptions but workflowType must be defined

GetLogAttributesInput​

Ƭ GetLogAttributesInput: Record<string, unknown>

Input for WorkflowOutboundCallsInterceptor.getLogAttributes

Sink​

Ƭ Sink: Record<string, SinkFunction>

A mapping of name to function, defines a single sink (e.g. logger)

SinkFunction​

Ƭ SinkFunction: (...args: any[]) => void

Type declaration​

▸ (...args): void

Any function signature can be used for Sink functions as long as the return type is void.

When calling a Sink function, arguments are copied from the Workflow isolate to the Node.js environment using postMessage.

This constrains the argument types to primitives (excluding Symbols).

Parameters​
NameType
...argsany[]
Returns​

void

Sinks​

Ƭ Sinks: Record<string, Sink>

Workflow Sink are a mapping of name to Sink

WithWorkflowArgs​

Ƭ WithWorkflowArgs<W, T>: T & Parameters<W> extends [any, ...any[]] ? { args: Parameters<W> | Readonly<Parameters<W>> } : { args?: Parameters<W> | Readonly<Parameters<W>> }

Type parameters​

NameType
Wextends Workflow
TT

WorkflowInterceptorsFactory​

Ƭ WorkflowInterceptorsFactory: () => WorkflowInterceptors

Type declaration​

▸ (): WorkflowInterceptors

A function that returns WorkflowInterceptors and takes no arguments.

Workflow interceptor modules should export an interceptors function of this type.

Example

export function interceptors(): WorkflowInterceptors {
  return {
    inbound: [],   // Populate with list of interceptor implementations
    outbound: [],  // Populate with list of interceptor implementations
    internals: [], // Populate with list of interceptor implementations
  };
}
Returns​

WorkflowInterceptors

Variables​

AsyncLocalStorage​

• Const AsyncLocalStorage: <T>() => ALS<T>

Type declaration​

• <T>()

Type parameters​
Name
T

NotAnActivityMethod​

• Const NotAnActivityMethod: unique symbol

Symbol used in the return type of proxy methods to mark that an attribute on the source type is not a method.

See

enhancedStackTraceQuery​

• Const enhancedStackTraceQuery: QueryDefinition<EnhancedStackTrace, [], string>

log​

• Const log: WorkflowLogger

Default workflow logger.

This logger is replay-aware and will omit log messages on workflow replay. Messages emitted by this logger are funnelled through a sink that forwards them to the logger registered on Runtime.logger.

Notice that since sinks are used to power this logger, any log attributes must be transferable via the postMessage API.

NOTE: Specifying a custom logger through defaultSink or by manually registering a sink named defaultWorkerLogger has been deprecated. Please use Runtime.logger instead.

stackTraceQuery​

• Const stackTraceQuery: QueryDefinition<string, [], string>

Functions​

addDefaultWorkflowOptions​

▸ addDefaultWorkflowOptions<T>(opts): ChildWorkflowOptionsWithDefaults

Adds default values to workflowId and workflowIdReusePolicy to given workflow options.

Type parameters​

NameType
Textends Workflow

Parameters​

NameType
optsWithWorkflowArgs<T, ChildWorkflowOptions>

Returns​

ChildWorkflowOptionsWithDefaults

condition​

▸ condition(fn, timeout): Promise<boolean>

Returns a Promise that resolves when fn evaluates to true or timeout expires.

Parameters​

NameTypeDescription
fn() => boolean-
timeoutDurationnumber of milliseconds or ms-formatted string

Returns​

Promise<boolean>

a boolean indicating whether the condition was true before the timeout expires

▸ condition(fn): Promise<void>

Returns a Promise that resolves when fn evaluates to true.

Parameters​

NameType
fn() => boolean

Returns​

Promise<void>

continueAsNew​

▸ continueAsNew<F>(...args): Promise<never>

Continues-As-New the current Workflow Execution with default options.

Shorthand for makeContinueAsNewFunc<F>()(...args). (See: makeContinueAsNewFunc.)

Example

import { continueAsNew } from '@temporalio/workflow';

export async function myWorkflow(n: number): Promise<void> {
 // ... Workflow logic
 await continueAsNew<typeof myWorkflow>(n + 1);
}

Type parameters​

NameType
Fextends Workflow

Parameters​

NameType
...argsParameters<F>

Returns​

Promise<never>

defineQuery​

▸ defineQuery<Ret, Args, Name>(name): QueryDefinition<Ret, Args, Name>

Define a query method for a Workflow.

Definitions are used to register handler in the Workflow via setHandler and to query Workflows using a WorkflowHandle. Definitions can be reused in multiple Workflows.

Type parameters​

NameType
RetRet
Argsextends any[] = []
Nameextends string = string

Parameters​

NameType
nameName

Returns​

QueryDefinition<Ret, Args, Name>

defineSignal​

▸ defineSignal<Args, Name>(name): SignalDefinition<Args, Name>

Define a signal method for a Workflow.

Definitions are used to register handler in the Workflow via setHandler and to signal Workflows using a WorkflowHandle, ChildWorkflowHandle or ExternalWorkflowHandle. Definitions can be reused in multiple Workflows.

Type parameters​

NameType
Argsextends any[] = []
Nameextends string = string

Parameters​

NameType
nameName

Returns​

SignalDefinition<Args, Name>

deprecatePatch​

▸ deprecatePatch(patchId): void

Indicate that a patch is being phased out.

See docs page for info.

Workflows with this call may be deployed alongside workflows with a patched call, but they must not be deployed while any workers still exist running old code without a patched call, or any runs with histories produced by such workers exist. If either kind of worker encounters a history produced by the other, their behavior is undefined.

Once all live workflow runs have been produced by workers with this call, you can deploy workers which are free of either kind of patch call for this ID. Workers with and without this call may coexist, as long as they are both running the "new" code.

Parameters​

NameTypeDescription
patchIdstringAn identifier that should be unique to this patch. It is OK to use multiple calls with the same ID, which means all such calls will always return the same value.

Returns​

void

executeChild​

▸ executeChild<T>(workflowType, options): Promise<WorkflowResultType<T>>

Start a child Workflow execution and await its completion.

  • By default, a child will be scheduled on the same task queue as its parent.
  • This operation is cancellable using CancellationScopes.

Type parameters​

NameType
Textends Workflow

Parameters​

NameType
workflowTypestring
optionsWithWorkflowArgs<T, ChildWorkflowOptions>

Returns​

Promise<WorkflowResultType<T>>

The result of the child Workflow.

▸ executeChild<T>(workflowFunc, options): Promise<WorkflowResultType<T>>

Start a child Workflow execution and await its completion.

  • By default, a child will be scheduled on the same task queue as its parent.
  • Deduces the Workflow type and signature from provided Workflow function.
  • This operation is cancellable using CancellationScopes.

Type parameters​

NameType
Textends Workflow

Parameters​

NameType
workflowFuncT
optionsWithWorkflowArgs<T, ChildWorkflowOptions>

Returns​

Promise<WorkflowResultType<T>>

The result of the child Workflow.

▸ executeChild<T>(workflowType): Promise<WorkflowResultType<T>>

Start a child Workflow execution and await its completion.

Override for Workflows that accept no arguments.

  • The child will be scheduled on the same task queue as its parent.
  • This operation is cancellable using CancellationScopes.

Type parameters​

NameType
Textends () => WorkflowReturnType

Parameters​

NameType
workflowTypestring

Returns​

Promise<WorkflowResultType<T>>

The result of the child Workflow.

▸ executeChild<T>(workflowFunc): Promise<WorkflowResultType<T>>

Start a child Workflow execution and await its completion.

Override for Workflows that accept no arguments.

  • The child will be scheduled on the same task queue as its parent.
  • Deduces the Workflow type and signature from provided Workflow function.
  • This operation is cancellable using CancellationScopes.

Type parameters​

NameType
Textends () => WorkflowReturnType

Parameters​

NameType
workflowFuncT

Returns​

Promise<WorkflowResultType<T>>

The result of the child Workflow.

extractWorkflowType​

▸ extractWorkflowType<T>(workflowTypeOrFunc): string

Type parameters​

NameType
Textends Workflow

Parameters​

NameType
workflowTypeOrFuncstring | T

Returns​

string

getExternalWorkflowHandle​

▸ getExternalWorkflowHandle(workflowId, runId?): ExternalWorkflowHandle

Returns a client-side handle that can be used to signal and cancel an existing Workflow execution. It takes a Workflow ID and optional run ID.

Parameters​

NameType
workflowIdstring
runId?string

Returns​

ExternalWorkflowHandle

inWorkflowContext​

▸ inWorkflowContext(): boolean

Returns whether or not code is executing in workflow context

Returns​

boolean

isCancellation​

▸ isCancellation(err): boolean

Returns whether provided err is caused by cancellation

Parameters​

NameType
errunknown

Returns​

boolean

makeContinueAsNewFunc​

▸ makeContinueAsNewFunc<F>(options?): (...args: Parameters<F>) => Promise<never>

Returns a function f that will cause the current Workflow to ContinueAsNew when called.

f takes the same arguments as the Workflow function supplied to typeparam F.

Once f is called, Workflow Execution immediately completes.

Type parameters​

NameType
Fextends Workflow

Parameters​

NameType
options?ContinueAsNewOptions

Returns​

fn

▸ (...args): Promise<never>

Parameters​
NameType
...argsParameters<F>
Returns​

Promise<never>

patched​

▸ patched(patchId): boolean

Patch or upgrade workflow code by checking or stating that this workflow has a certain patch.

See docs page for info.

If the workflow is replaying an existing history, then this function returns true if that history was produced by a worker which also had a patched call with the same patchId. If the history was produced by a worker without such a call, then it will return false.

If the workflow is not currently replaying, then this call always returns true.

Your workflow code should run the "new" code if this returns true, if it returns false, you should run the "old" code. By doing this, you can maintain determinism.

Parameters​

NameTypeDescription
patchIdstringAn identifier that should be unique to this patch. It is OK to use multiple calls with the same ID, which means all such calls will always return the same value.

Returns​

boolean

proxyActivities​

▸ proxyActivities<A>(options): ActivityInterfaceFor<A>

Configure Activity functions with given ActivityOptions.

This method may be called multiple times to setup Activities with different options.

Example

import { proxyActivities } from '@temporalio/workflow';
import * as activities from '../activities';

// Setup Activities from module exports
const { httpGet, otherActivity } = proxyActivities<typeof activities>({
  startToCloseTimeout: '30 minutes',
});

// Setup Activities from an explicit interface (e.g. when defined by another SDK)
interface JavaActivities {
  httpGetFromJava(url: string): Promise<string>
  someOtherJavaActivity(arg1: number, arg2: string): Promise<string>;
}

const {
  httpGetFromJava,
  someOtherJavaActivity
} = proxyActivities<JavaActivities>({
  taskQueue: 'java-worker-taskQueue',
  startToCloseTimeout: '5m',
});

export function execute(): Promise<void> {
  const response = await httpGet("http://example.com");
  // ...
}

Type parameters​

NameType
AUntypedActivities

Parameters​

NameType
optionsActivityOptions

Returns​

ActivityInterfaceFor<A>

a Proxy for which each attribute is a callable Activity function

proxyLocalActivities​

▸ proxyLocalActivities<A>(options): ActivityInterfaceFor<A>

Configure Local Activity functions with given LocalActivityOptions.

This method may be called multiple times to setup Activities with different options.

See

proxyActivities for examples

Type parameters​

NameType
AUntypedActivities

Parameters​

NameType
optionsLocalActivityOptions

Returns​

ActivityInterfaceFor<A>

a Proxy for which each attribute is a callable Activity function

proxySinks​

▸ proxySinks<T>(): T

Get a reference to Sinks for exporting data out of the Workflow.

These Sinks must be registered with the Worker in order for this mechanism to work.

Example

import { proxySinks, Sinks } from '@temporalio/workflow';

interface MySinks extends Sinks {
  logger: {
    info(message: string): void;
    error(message: string): void;
  };
}

const { logger } = proxySinks<MyDependencies>();
logger.info('setting up');

export function myWorkflow() {
  return {
    async execute() {
      logger.info("hey ho");
      logger.error("lets go");
    }
  };
}

Type parameters​

NameType
Textends Sinks

Returns​

T

setDefaultSignalHandler​

▸ setDefaultSignalHandler(handler): void

Set a signal handler function that will handle signals calls for non-registered signal names.

Signals are dispatched to the default signal handler in the order that they were accepted by the server.

If this function is called multiple times for a given signal or query name the last handler will overwrite any previous calls.

Parameters​

NameTypeDescription
handlerundefined | DefaultSignalHandlera function that will handle signals for non-registered signal names, or undefined to unset the handler.

Returns​

void

setHandler​

▸ setHandler<Ret, Args, T>(def, handler): void

Set a handler function for a Workflow query or signal.

If this function is called multiple times for a given signal or query name the last handler will overwrite any previous calls.

Type parameters​

NameType
RetRet
Argsextends any[]
Textends SignalDefinition<Args, string> | QueryDefinition<Ret, Args, string>

Parameters​

NameTypeDescription
defTa SignalDefinition or QueryDefinition as returned by defineSignal or defineQuery respectively.
handlerundefined | Handler<Ret, Args, T>a compatible handler function for the given definition or undefined to unset the handler.

Returns​

void

sleep​

▸ sleep(ms): Promise<void>

Asynchronous sleep.

Schedules a timer on the Temporal service.

Parameters​

NameTypeDescription
msDurationsleep duration - number of milliseconds or ms-formatted string. If given a negative number or 0, value will be set to 1.

Returns​

Promise<void>

startChild​

▸ startChild<T>(workflowType, options): Promise<ChildWorkflowHandle<T>>

Start a child Workflow execution

  • Returns a client-side handle that implements a child Workflow interface.
  • By default, a child will be scheduled on the same task queue as its parent.

A child Workflow handle supports awaiting completion, signaling and cancellation via CancellationScopes. In order to query the child, use a WorkflowClient from an Activity.

Type parameters​

NameType
Textends Workflow

Parameters​

NameType
workflowTypestring
optionsWithWorkflowArgs<T, ChildWorkflowOptions>

Returns​

Promise<ChildWorkflowHandle<T>>

▸ startChild<T>(workflowFunc, options): Promise<ChildWorkflowHandle<T>>

Start a child Workflow execution

  • Returns a client-side handle that implements a child Workflow interface.
  • Deduces the Workflow type and signature from provided Workflow function.
  • By default, a child will be scheduled on the same task queue as its parent.

A child Workflow handle supports awaiting completion, signaling and cancellation via CancellationScopes. In order to query the child, use a WorkflowClient from an Activity.

Type parameters​

NameType
Textends Workflow

Parameters​

NameType
workflowFuncT
optionsWithWorkflowArgs<T, ChildWorkflowOptions>

Returns​

Promise<ChildWorkflowHandle<T>>

▸ startChild<T>(workflowType): Promise<ChildWorkflowHandle<T>>

Start a child Workflow execution

Override for Workflows that accept no arguments.

  • Returns a client-side handle that implements a child Workflow interface.
  • The child will be scheduled on the same task queue as its parent.

A child Workflow handle supports awaiting completion, signaling and cancellation via CancellationScopes. In order to query the child, use a WorkflowClient from an Activity.

Type parameters​

NameType
Textends () => Promise<any>

Parameters​

NameType
workflowTypestring

Returns​

Promise<ChildWorkflowHandle<T>>

▸ startChild<T>(workflowFunc): Promise<ChildWorkflowHandle<T>>

Start a child Workflow execution

Override for Workflows that accept no arguments.

  • Returns a client-side handle that implements a child Workflow interface.
  • Deduces the Workflow type and signature from provided Workflow function.
  • The child will be scheduled on the same task queue as its parent.

A child Workflow handle supports awaiting completion, signaling and cancellation via CancellationScopes. In order to query the child, use a WorkflowClient from an Activity.

Type parameters​

NameType
Textends () => Promise<any>

Parameters​

NameType
workflowFuncT

Returns​

Promise<ChildWorkflowHandle<T>>

upsertSearchAttributes​

▸ upsertSearchAttributes(searchAttributes): void

Updates this Workflow's Search Attributes by merging the provided searchAttributes with the existing Search Attributes, workflowInfo().searchAttributes.

For example, this Workflow code:

upsertSearchAttributes({
  CustomIntField: [1],
  CustomBoolField: [true]
});
upsertSearchAttributes({
  CustomIntField: [42],
  CustomKeywordField: ['durable code', 'is great']
});

would result in the Workflow having these Search Attributes:

{
  CustomIntField: [42],
  CustomBoolField: [true],
  CustomKeywordField: ['durable code', 'is great']
}

Parameters​

NameTypeDescription
searchAttributesSearchAttributesThe Record to merge. Use a value of [] to clear a Search Attribute.

Returns​

void

uuid4​

▸ uuid4(): string

Generate an RFC compliant V4 uuid. Uses the workflow's deterministic PRNG making it safe for use within a workflow. This function is cryptographically insecure. See the stackoverflow discussion.

Returns​

string

workflowInfo​

▸ workflowInfo(): WorkflowInfo

Get information about the current Workflow.

WARNING: This function returns a frozen copy of WorkflowInfo, at the point where this method has been called. Changes happening at later point in workflow execution will not be reflected in the returned object.

For this reason, we recommend calling workflowInfo() on every access to WorkflowInfo's fields, rather than caching the WorkflowInfo object (or part of it) in a local variable. For example:

// GOOD
function myWorkflow() {
  doSomething(workflowInfo().searchAttributes)
  ...
  doSomethingElse(workflowInfo().searchAttributes)
}

vs

// BAD
function myWorkflow() {
  const attributes = workflowInfo().searchAttributes
  doSomething(attributes)
  ...
  doSomethingElse(attributes)
}

Returns​

WorkflowInfo