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Merged
JoshuaFrenchwood merged 3 commits into from
Aug 27, 2026
Merged

Adding nexus TemporalOperationHandler to nexus-messaging examples #513

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b7a6982
Adding nexus TemporalOperationHandler to nexus-messaging examples
JoshuaFrenchwood Aug 24, 2026
365dc24
Adding Async Update
JoshuaFrenchwood Aug 25, 2026
4f0a515
Adding config value for signal backlinks
JoshuaFrenchwood Aug 26, 2026
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23 changes: 14 additions & 9 deletions nexus-messaging/src/callerpattern/README.md
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Original file line number Diff line number Diff line change
@@ -1,9 +1,9 @@
## Caller pattern

The handler worker starts a `GreetingWorkflow` for a user ID at boot.
`NexusGreetingService` holds that ID and routes every Nexus operation to it.
`nexusGreetingServiceHandler` derives the workflow ID and routes every Nexus operation to it.
The caller's input does not have that workflow ID as the caller doesn't know it -- but the caller sends in the User ID,
and `NexusGreetingService` knows how to get the desired workflow ID from that User ID (via the `GreetingWorkflow_for_<userId>` prefix).
and `nexusGreetingServiceHandler` knows how to get the desired workflow ID from that User ID (via the `GreetingWorkflow_for_<userId>` prefix).

The handler worker uses the same prefix to generate a workflow ID from a user ID when it launches the workflow.

Expand All @@ -16,19 +16,24 @@ The caller workflow:

### Running

Start a Temporal server:
Start a compatible Temporal dev server with Workflow Update callbacks enabled:

```bash
temporal server start-dev
./temporal server start-dev \

@Quinn-With-Two-Ns Quinn-With-Two-Ns Aug 26, 2026

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I think we would also need history.enableCHASMSignalBacklinks

@JoshuaFrenchwood JoshuaFrenchwood Aug 26, 2026

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Thanks, updated

--dynamic-config-value history.enableCHASMCallbacks=true \
--dynamic-config-value history.enableUpdateCallbacks=true \
--dynamic-config-value history.enableCHASMSignalBacklinks=true \
--namespace nexus-messaging-handler-namespace \
--namespace nexus-messaging-caller-namespace
```

Create the namespaces and Nexus endpoint:
This sample requires a Temporal dev-server build that supports Workflow Update callbacks. Download the compatible
binary from the [Temporal CLI pre-release instructions](https://docs.temporal.io/standalone-nexus-operation#temporal-cli-support).

```bash
temporal operator namespace create --namespace nexus-messaging-handler-namespace
temporal operator namespace create --namespace nexus-messaging-caller-namespace
Create the Nexus endpoint:

temporal operator nexus endpoint create \
```bash
./temporal operator nexus endpoint create \
--name nexus-messaging-nexus-endpoint \
--target-namespace nexus-messaging-handler-namespace \
--target-task-queue nexus-messaging-handler-task-queue
Expand Down
47 changes: 27 additions & 20 deletions nexus-messaging/src/callerpattern/service/handler.ts
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Expand Up @@ -8,27 +8,34 @@ function workflowIdForUser(userId: string): string {
}

export const nexusGreetingServiceHandler = nexus.serviceHandler(nexusGreetingService, {
getLanguages: async (ctx, input: GetLanguagesInput) => {
const client = temporalNexus.getClient();
const handle = client.workflow.getHandle(workflowIdForUser(input.userId));
return await handle.query(getLanguagesQuery);
},
getLanguages: new temporalNexus.TemporalOperationHandler({
async start(_ctx, client, input: GetLanguagesInput) {
const handle = client.client.workflow.getHandle(workflowIdForUser(input.userId));
const result = await handle.query(getLanguagesQuery);
return temporalNexus.TemporalOperationResult.sync(result);
},
}),

getLanguage: async (ctx, input: GetLanguageInput) => {
const client = temporalNexus.getClient();
const handle = client.workflow.getHandle(workflowIdForUser(input.userId));
return await handle.query(getLanguageQuery);
},
getLanguage: new temporalNexus.TemporalOperationHandler({
async start(_ctx, client, input: GetLanguageInput) {
const handle = client.client.workflow.getHandle(workflowIdForUser(input.userId));
const result = await handle.query(getLanguageQuery);
return temporalNexus.TemporalOperationResult.sync(result);
},
}),

setLanguage: async (ctx, input: SetLanguageInput) => {
const client = temporalNexus.getClient();
const handle = client.workflow.getHandle(workflowIdForUser(input.userId));
return await handle.executeUpdate(setLanguageUpdate, { args: [input.language] });
},
setLanguage: new temporalNexus.TemporalOperationHandler({
async start(_ctx, client, input: SetLanguageInput) {
const handle = client.getWorkflowHandle(workflowIdForUser(input.userId));
return await handle.update(setLanguageUpdate, { args: [input.language] });
},
}),

approve: async (ctx, input: ApproveInput) => {
const client = temporalNexus.getClient();
const handle = client.workflow.getHandle(workflowIdForUser(input.userId));
await handle.signal(approveSignal);
},
approve: new temporalNexus.TemporalOperationHandler({
async start(_ctx, client, input: ApproveInput) {
const handle = client.getWorkflowHandle(workflowIdForUser(input.userId));
await handle.signal(approveSignal);
return temporalNexus.TemporalOperationResult.sync(undefined);
},
}),
});
19 changes: 12 additions & 7 deletions nexus-messaging/src/ondemandpattern/README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -15,19 +15,24 @@ The caller workflow:

### Running

Start a Temporal server:
Start a compatible Temporal dev server with Workflow Update callbacks enabled:

```bash
temporal server start-dev
./temporal server start-dev \
--dynamic-config-value history.enableCHASMCallbacks=true \
--dynamic-config-value history.enableUpdateCallbacks=true \
--dynamic-config-value history.enableCHASMSignalBacklinks=true \
--namespace nexus-messaging-handler-namespace \
--namespace nexus-messaging-caller-namespace
```

Create the namespaces and Nexus endpoint:
This sample requires a Temporal dev-server build that supports Workflow Update callbacks. Download the compatible
binary from the [Temporal CLI pre-release instructions](https://docs.temporal.io/standalone-nexus-operation#temporal-cli-support).

```bash
temporal operator namespace create --namespace nexus-messaging-handler-namespace
temporal operator namespace create --namespace nexus-messaging-caller-namespace
Create the Nexus endpoint:

temporal operator nexus endpoint create \
```bash
./temporal operator nexus endpoint create \
--name nexus-messaging-nexus-endpoint \
--target-namespace nexus-messaging-handler-namespace \
--target-task-queue nexus-messaging-handler-task-queue
Expand Down
47 changes: 27 additions & 20 deletions nexus-messaging/src/ondemandpattern/service/handler.ts
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Expand Up @@ -27,27 +27,34 @@ export const nexusRemoteGreetingServiceHandler = nexus.serviceHandler(nexusRemot
},
),

getLanguages: async (ctx, input: GetLanguagesInput) => {
const client = temporalNexus.getClient();
const handle = client.workflow.getHandle(getWorkflowId(input.userId));
return await handle.query(getLanguagesQuery);
},
getLanguages: new temporalNexus.TemporalOperationHandler({
async start(_ctx, client, input: GetLanguagesInput) {
const handle = client.client.workflow.getHandle(getWorkflowId(input.userId));
const result = await handle.query(getLanguagesQuery);
return temporalNexus.TemporalOperationResult.sync(result);
},
}),

getLanguage: async (ctx, input: GetLanguageInput) => {
const client = temporalNexus.getClient();
const handle = client.workflow.getHandle(getWorkflowId(input.userId));
return await handle.query(getLanguageQuery);
},
getLanguage: new temporalNexus.TemporalOperationHandler({
async start(_ctx, client, input: GetLanguageInput) {
const handle = client.client.workflow.getHandle(getWorkflowId(input.userId));
const result = await handle.query(getLanguageQuery);
return temporalNexus.TemporalOperationResult.sync(result);
},
}),

setLanguage: async (ctx, input: SetLanguageInput) => {
const client = temporalNexus.getClient();
const handle = client.workflow.getHandle(getWorkflowId(input.userId));
return await handle.executeUpdate(setLanguageUpdate, { args: [input.language] });
},
setLanguage: new temporalNexus.TemporalOperationHandler({
async start(_ctx, client, input: SetLanguageInput) {
const handle = client.getWorkflowHandle(getWorkflowId(input.userId));
return await handle.update(setLanguageUpdate, { args: [input.language] });
},
}),

approve: async (ctx, input: ApproveInput) => {
const client = temporalNexus.getClient();
const handle = client.workflow.getHandle(getWorkflowId(input.userId));
await handle.signal(approveSignal);
},
approve: new temporalNexus.TemporalOperationHandler({
async start(_ctx, client, input: ApproveInput) {
const handle = client.getWorkflowHandle(getWorkflowId(input.userId));
await handle.signal(approveSignal);
return temporalNexus.TemporalOperationResult.sync(undefined);
},
}),
});