From 720fb08846874d2c3a3b4560ad80183e65691e6e Mon Sep 17 00:00:00 2001 From: Alice Lin Date: Tue, 8 Sep 2026 21:19:15 -0700 Subject: [PATCH 1/3] Add Nexus Signal-with-Start example --- nexus-messaging/src/ondemandpattern/README.md | 16 ++++++++---- nexus-messaging/src/ondemandpattern/api.ts | 11 ++++++++ .../src/ondemandpattern/caller/workflows.ts | 23 +++++++++++++++- .../src/ondemandpattern/service/handler.ts | 26 ++++++++++++++++++- .../src/ondemandpattern/service/workflows.ts | 10 ++++++- 5 files changed, 78 insertions(+), 8 deletions(-) diff --git a/nexus-messaging/src/ondemandpattern/README.md b/nexus-messaging/src/ondemandpattern/README.md index 4e35d9e9f..d877bf4ba 100644 --- a/nexus-messaging/src/ondemandpattern/README.md +++ b/nexus-messaging/src/ondemandpattern/README.md @@ -7,11 +7,14 @@ instance to target. The caller workflow: -1. Starts two remote `GreetingWorkflow` instances via `runFromRemote` (backed by `WorkflowRunOperation`) -2. Queries supported languages from workflow one and the current language from workflow two -3. Changes the language on each (Spanish and Hindi) -4. Approves both workflows -5. Waits for each to complete and returns their results +1. Attaches approval context for user one via `attachApprovalContext`, before anything has started + that user's workflow +2. Starts two remote `GreetingWorkflow` instances via `runFromRemote` (backed by `WorkflowRunOperation`) +3. Attaches approval context for user two, whose workflow now already exists +4. Queries supported languages from workflow one and the current language from workflow two +5. Changes the language on each (Spanish and Hindi) +6. Approves both workflows +7. Waits for each to complete and returns their results ### Running @@ -22,6 +25,7 @@ Start a compatible Temporal dev server with Workflow Update callbacks enabled: --dynamic-config-value history.enableCHASMCallbacks=true \ --dynamic-config-value history.enableUpdateCallbacks=true \ --dynamic-config-value history.enableCHASMSignalBacklinks=true \ + --dynamic-config-value history.enableSignalWithStartFromWorkflow=true \ --namespace nexus-messaging-handler-namespace \ --namespace nexus-messaging-caller-namespace ``` @@ -65,8 +69,10 @@ npm run workflow.ondemandpattern Expected output: ``` + attached approval context for user: UserId_One started workflow one for user: UserId_One started workflow two for user: UserId_Two + attached approval context to running workflow for user: UserId_Two workflow one languages: chinese, english workflow one: set language to spanish, previous was: english workflow two current language: english diff --git a/nexus-messaging/src/ondemandpattern/api.ts b/nexus-messaging/src/ondemandpattern/api.ts index 5e8e74427..fe0748880 100644 --- a/nexus-messaging/src/ondemandpattern/api.ts +++ b/nexus-messaging/src/ondemandpattern/api.ts @@ -30,6 +30,12 @@ export const nexusRemoteGreetingService = nexus.service('NexusRemoteGreetingServ * Approves (completes) the given workflow via a signal. */ approve: nexus.operation(), + + /** + * Attaches supporting information for the eventual approval, either by messaging a running + * Workflow or by creating one (Signal-with-Start). + */ + attachApprovalContext: nexus.operation(), }); export type Language = 'arabic' | 'chinese' | 'english' | 'french' | 'hindi' | 'portuguese' | 'spanish'; @@ -62,3 +68,8 @@ export type SetLanguageOutput = Language; export interface ApproveInput { userId: string; } + +export interface AttachApprovalContextInput { + userId: string; + note: string; +} diff --git a/nexus-messaging/src/ondemandpattern/caller/workflows.ts b/nexus-messaging/src/ondemandpattern/caller/workflows.ts index 4b5e91942..d91e2db1b 100644 --- a/nexus-messaging/src/ondemandpattern/caller/workflows.ts +++ b/nexus-messaging/src/ondemandpattern/caller/workflows.ts @@ -12,7 +12,19 @@ export async function callerRemoteWorkflow(): Promise { const userIdOne = 'UserId_One'; const userIdTwo = 'UserId_Two'; - // Start both remote workflows concurrently + // Attach approval context before anything has started Workflow One. Because + // attachApprovalContext is backed by Signal-with-Start on the handler, this call creates the + // Workflow and delivers the note to it. + await nexusClient.executeOperation( + 'attachApprovalContext', + { userId: userIdOne, note: 'queued for localization review by the nightly batch' }, + { scheduleToCloseTimeout: '10s' }, + ); + log.push(`attached approval context for user: ${userIdOne}`); + + // Start both remote workflows concurrently. Workflow One is already running because of the call + // above; the handler sets the conflict policy to USE_EXISTING, so that start attaches the + // operation's completion callback to the running execution instead of failing. const [handleOne, handleTwo] = await Promise.all([ nexusClient.startOperation('runFromRemote', { userId: userIdOne }, { scheduleToCloseTimeout: '60s' }), nexusClient.startOperation('runFromRemote', { userId: userIdTwo }, { scheduleToCloseTimeout: '60s' }), @@ -21,6 +33,15 @@ export async function callerRemoteWorkflow(): Promise { log.push(`started workflow one for user: ${userIdOne}`); log.push(`started workflow two for user: ${userIdTwo}`); + // Workflow Two was just created by runFromRemote, so here Signal-with-Start skips the start and + // only delivers the Signal. + await nexusClient.executeOperation( + 'attachApprovalContext', + { userId: userIdTwo, note: 'translation approved by the localization team' }, + { scheduleToCloseTimeout: '10s' }, + ); + log.push(`attached approval context to running workflow for user: ${userIdTwo}`); + // Interact with workflow one: query languages, set language to spanish const languagesOne = await nexusClient.executeOperation( 'getLanguages', diff --git a/nexus-messaging/src/ondemandpattern/service/handler.ts b/nexus-messaging/src/ondemandpattern/service/handler.ts index aae3f67c5..9ae1d4d2f 100644 --- a/nexus-messaging/src/ondemandpattern/service/handler.ts +++ b/nexus-messaging/src/ondemandpattern/service/handler.ts @@ -2,6 +2,7 @@ import * as nexus from 'nexus-rpc'; import * as temporalNexus from '@temporalio/nexus'; import { ApproveInput, + AttachApprovalContextInput, GetLanguageInput, GetLanguagesInput, nexusRemoteGreetingService, @@ -9,7 +10,14 @@ import { RunFromRemoteOutput, SetLanguageInput, } from '../api'; -import { approveSignal, getLanguageQuery, getLanguagesQuery, greetingWorkflow, setLanguageUpdate } from './workflows'; +import { + approveSignal, + attachApprovalContextSignal, + getLanguageQuery, + getLanguagesQuery, + greetingWorkflow, + setLanguageUpdate, +} from './workflows'; const WORKFLOW_ID_PREFIX = 'GreetingWorkflow_for_'; @@ -23,6 +31,9 @@ export const nexusRemoteGreetingServiceHandler = nexus.serviceHandler(nexusRemot return await temporalNexus.startWorkflow(ctx, greetingWorkflow, { args: [], workflowId: getWorkflowId(input.userId), + // attachApprovalContext may have created the GreetingWorkflow already, so attach to the + // running execution instead of failing (the default behavior). + workflowIdConflictPolicy: 'USE_EXISTING', }); }, ), @@ -57,4 +68,17 @@ export const nexusRemoteGreetingServiceHandler = nexus.serviceHandler(nexusRemot return temporalNexus.TemporalOperationResult.sync(undefined); }, }), + + // Signals the Workflow, starting it first if it is not already running. + attachApprovalContext: new temporalNexus.TemporalOperationHandler({ + async start(_ctx, client, input: AttachApprovalContextInput) { + await client.signalWithStartWorkflow(greetingWorkflow, { + args: [], + workflowId: getWorkflowId(input.userId), + signal: attachApprovalContextSignal, + signalArgs: [input], + }); + return temporalNexus.TemporalOperationResult.sync(undefined); + }, + }), }); diff --git a/nexus-messaging/src/ondemandpattern/service/workflows.ts b/nexus-messaging/src/ondemandpattern/service/workflows.ts index d09d1de99..8493bd1e2 100644 --- a/nexus-messaging/src/ondemandpattern/service/workflows.ts +++ b/nexus-messaging/src/ondemandpattern/service/workflows.ts @@ -1,5 +1,5 @@ import * as wf from '@temporalio/workflow'; -import { Language } from '../api'; +import { AttachApprovalContextInput, Language } from '../api'; import { createActivities } from './activities'; const { callGreetingService } = wf.proxyActivities>({ @@ -11,6 +11,7 @@ export const getLanguageQuery = wf.defineQuery('getLanguage'); export const setLanguageUpdate = wf.defineUpdate('setLanguage'); export const setLanguageUsingActivityUpdate = wf.defineUpdate('setLanguageUsingActivity'); export const approveSignal = wf.defineSignal<[]>('approve'); +export const attachApprovalContextSignal = wf.defineSignal<[AttachApprovalContextInput]>('attachApprovalContext'); const INITIAL_GREETINGS: Partial> = { chinese: '你好，世界', @@ -21,6 +22,7 @@ export async function greetingWorkflow(): Promise { let language: Language = 'english'; let greetings: Partial> = { ...INITIAL_GREETINGS }; let approved = false; + let approvalContext: string | undefined; wf.setHandler(getLanguagesQuery, () => Object.keys(greetings) as Language[]); @@ -56,9 +58,15 @@ export async function greetingWorkflow(): Promise { }); wf.setHandler(approveSignal, () => { + wf.log.info('approve signal received', { approvalContext }); approved = true; }); + wf.setHandler(attachApprovalContextSignal, (input: AttachApprovalContextInput) => { + wf.log.info('attachApprovalContext signal received', { userId: input.userId, note: input.note }); + approvalContext = input.note; + }); + await wf.condition(() => approved && wf.allHandlersFinished()); return greetings[language] ?? `Hello from ${language}`; From 89a3605826ba1799ecf6ea6d8ea4e3a637a233ea Mon Sep 17 00:00:00 2001 From: Alice Lin Date: Wed, 9 Sep 2026 17:42:22 -0700 Subject: [PATCH 2/3] Change WorkflowRunOperation to TemporalOperation --- nexus-messaging/src/ondemandpattern/README.md | 2 +- nexus-messaging/src/ondemandpattern/api.ts | 2 +- nexus-messaging/src/ondemandpattern/service/handler.ts | 8 ++++---- 3 files changed, 6 insertions(+), 6 deletions(-) diff --git a/nexus-messaging/src/ondemandpattern/README.md b/nexus-messaging/src/ondemandpattern/README.md index d877bf4ba..ebc91ac59 100644 --- a/nexus-messaging/src/ondemandpattern/README.md +++ b/nexus-messaging/src/ondemandpattern/README.md @@ -9,7 +9,7 @@ The caller workflow: 1. Attaches approval context for user one via `attachApprovalContext`, before anything has started that user's workflow -2. Starts two remote `GreetingWorkflow` instances via `runFromRemote` (backed by `WorkflowRunOperation`) +2. Starts two remote `GreetingWorkflow` instances via `runFromRemote` (backed by `TemporalOperation`) 3. Attaches approval context for user two, whose workflow now already exists 4. Queries supported languages from workflow one and the current language from workflow two 5. Changes the language on each (Spanish and Hindi) diff --git a/nexus-messaging/src/ondemandpattern/api.ts b/nexus-messaging/src/ondemandpattern/api.ts index fe0748880..c67839b1b 100644 --- a/nexus-messaging/src/ondemandpattern/api.ts +++ b/nexus-messaging/src/ondemandpattern/api.ts @@ -7,7 +7,7 @@ export const CALLER_NAMESPACE = 'nexus-messaging-caller-namespace'; export const nexusRemoteGreetingService = nexus.service('NexusRemoteGreetingService', { /** - * Starts a new GreetingWorkflow with the given workflowId (async WorkflowRunOperation). + * Starts a new GreetingWorkflow with the given workflowId (async TemporalOperation). */ runFromRemote: nexus.operation(), diff --git a/nexus-messaging/src/ondemandpattern/service/handler.ts b/nexus-messaging/src/ondemandpattern/service/handler.ts index 9ae1d4d2f..067007afc 100644 --- a/nexus-messaging/src/ondemandpattern/service/handler.ts +++ b/nexus-messaging/src/ondemandpattern/service/handler.ts @@ -26,9 +26,9 @@ function getWorkflowId(userId: string): string { } export const nexusRemoteGreetingServiceHandler = nexus.serviceHandler(nexusRemoteGreetingService, { - runFromRemote: new temporalNexus.WorkflowRunOperationHandler( - async (ctx, input: RunFromRemoteInput) => { - return await temporalNexus.startWorkflow(ctx, greetingWorkflow, { + runFromRemote: new temporalNexus.TemporalOperationHandler({ + async start(_ctx, client, input: RunFromRemoteInput) { + return await client.startWorkflow(greetingWorkflow, { args: [], workflowId: getWorkflowId(input.userId), // attachApprovalContext may have created the GreetingWorkflow already, so attach to the @@ -36,7 +36,7 @@ export const nexusRemoteGreetingServiceHandler = nexus.serviceHandler(nexusRemot workflowIdConflictPolicy: 'USE_EXISTING', }); }, - ), + }), getLanguages: new temporalNexus.TemporalOperationHandler({ async start(_ctx, client, input: GetLanguagesInput) { From e4a8abe595fd4ebed4959b2e058fad3d0412b4f3 Mon Sep 17 00:00:00 2001 From: Alice Lin Date: Thu, 10 Sep 2026 10:02:11 -0700 Subject: [PATCH 3/3] Update README --- nexus-messaging/src/ondemandpattern/README.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/nexus-messaging/src/ondemandpattern/README.md b/nexus-messaging/src/ondemandpattern/README.md index ebc91ac59..6ca1ca219 100644 --- a/nexus-messaging/src/ondemandpattern/README.md +++ b/nexus-messaging/src/ondemandpattern/README.md @@ -9,7 +9,7 @@ The caller workflow: 1. Attaches approval context for user one via `attachApprovalContext`, before anything has started that user's workflow -2. Starts two remote `GreetingWorkflow` instances via `runFromRemote` (backed by `TemporalOperation`) +2. Starts or attaches to two remote `GreetingWorkflow` instances via `runFromRemote` (backed by `TemporalOperation`) 3. Attaches approval context for user two, whose workflow now already exists 4. Queries supported languages from workflow one and the current language from workflow two 5. Changes the language on each (Spanish and Hindi)