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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.

Updates, Signals and Queries

Use setHandler to set handlers for Updates, Signals, and Queries.

Update and Signal handlers can be either async or non-async functions. Update handlers may return a value, but signal handlers may not (return void or Promise<void>). You may use Activities, Timers, child Workflows, etc in Update and Signal handlers, but this should be done cautiously: for example, note that if you await async operations such as these in an Update or Signal handler, then you are responsible for ensuring that the workflow does not complete first.

Query handlers may not be async functions, and may not mutate any variables or use Activities, Timers, child Workflows, etc.

Implementation

export const incrementSignal = wf.defineSignal<[number]>('increment');
export const getValueQuery = wf.defineQuery<number>('getValue');
export const incrementAndGetValueUpdate = wf.defineUpdate<number, [number]>('incrementAndGetValue');

export async function counterWorkflow(initialValue: number): Promise<void> {
let count = initialValue;
wf.setHandler(incrementSignal, (arg: number) => {
count += arg;
});
wf.setHandler(getValueQuery, () => count);
wf.setHandler(incrementAndGetValueUpdate, (arg: number): number => {
count += arg;
return count;
});
await wf.condition(() => false);
}

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


BaseWorkflowHandle

Re-exports BaseWorkflowHandle


BaseWorkflowOptions

Re-exports BaseWorkflowOptions


CancelledFailure

Re-exports CancelledFailure


ChildWorkflowFailure

Re-exports ChildWorkflowFailure


CommonWorkflowOptions

Re-exports CommonWorkflowOptions


Headers

Re-exports Headers


IllegalStateError

Re-exports IllegalStateError


NamespaceNotFoundError

Re-exports NamespaceNotFoundError


Next

Re-exports Next


Payload

Re-exports Payload


PayloadConverter

Re-exports PayloadConverter


PayloadConverterError

Re-exports PayloadConverterError


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


ValueError

Re-exports ValueError


WithWorkflowArgs

Re-exports WithWorkflowArgs


Workflow

Re-exports Workflow


WorkflowDurationOptions

Re-exports WorkflowDurationOptions


WorkflowExecutionAlreadyStartedError

Re-exports WorkflowExecutionAlreadyStartedError


WorkflowIdReusePolicy

Re-exports WorkflowIdReusePolicy


WorkflowNotFoundError

Re-exports WorkflowNotFoundError


WorkflowQueryType

Re-exports WorkflowQueryType


WorkflowResultType

Re-exports WorkflowResultType


WorkflowReturnType

Re-exports WorkflowReturnType


WorkflowSignalType

Re-exports WorkflowSignalType


defaultPayloadConverter

Re-exports defaultPayloadConverter


extractWorkflowType

Re-exports extractWorkflowType


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

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

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).

Type declaration

▸ (...args): void

Parameters
NameType
...argsany[]
Returns

void


Sinks

Ƭ Sinks: Record<string, Sink>

Workflow Sink are a mapping of name to Sink


WorkflowInterceptorsFactory

Ƭ WorkflowInterceptorsFactory: () => 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
};
}

Type declaration

▸ (): WorkflowInterceptors

Returns

WorkflowInterceptors

Variables

AsyncLocalStorage

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

Type declaration

• <T>(): ALS<T>

Type parameters
Name
T
Returns

ALS<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.

Attributes from the current Workflow Execution context are automatically included as metadata on every log entries. An extra sdkComponent metadata attribute is also added, with value workflow; this can be used for fine-grained filtering of log entries further downstream.

To customize log attributes, register a WorkflowOutboundCallsInterceptor that intercepts the getLogAttributes() method.

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>


workflowMetadataQuery

Const workflowMetadataQuery: QueryDefinition<IWorkflowMetadata, [], 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.)

Type parameters

NameType
Fextends Workflow

Parameters

NameType
...argsParameters<F>

Returns

Promise<never>

Example

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

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

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>


defineUpdate

defineUpdate<Ret, Args, Name>(name): UpdateDefinition<Ret, Args, Name>

Define an update method for a Workflow.

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

Type parameters

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

Parameters

NameType
nameName

Returns

UpdateDefinition<Ret, 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.


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.

Type parameters

NameType
AUntypedActivities

Parameters

NameType
optionsActivityOptions

Returns

ActivityInterfaceFor<A>

a Proxy for which each attribute is a callable Activity function

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");
// ...
}

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.

Type parameters

NameType
AUntypedActivities

Parameters

NameType
optionsLocalActivityOptions

Returns

ActivityInterfaceFor<A>

a Proxy for which each attribute is a callable Activity function

See

proxyActivities for examples


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.

Type parameters

NameType
Textends Sinks

Returns

T

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");
}
};
}

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, options?): void

Set a handler function for a Workflow update, signal, or query.

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

Type parameters

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

Parameters

NameTypeDescription
defTan UpdateDefinition, SignalDefinition, or QueryDefinition as returned by defineUpdate, defineSignal, or defineQuery respectively.
handlerundefined | Handler<Ret, Args, T>a compatible handler function for the given definition or undefined to unset the handler.
options?QueryHandlerOptionsan optional description of the handler and an optional update validator function.

Returns

void

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

Type parameters

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

Parameters

NameType
defT
handlerundefined | Handler<Ret, Args, T>
options?SignalHandlerOptions

Returns

void

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

Type parameters

NameType
RetRet
Argsextends any[]
Textends UpdateDefinition<Ret, Args, string>

Parameters

NameType
defT
handlerundefined | Handler<Ret, Args, T>
options?UpdateHandlerOptions<Args>

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