feat(workflow): Expose root workflow execution

packages/test/src/test-integration-workflows.ts

@@ -1081,6 +1081,30 @@ if (RUN_TIME_SKIPPING_TESTS) {
   });
 }
 
+export async function rootWorkflow(): Promise<string> {
+  let result = '';
+  if (!workflow.workflowInfo().rootWorkflow) {
+    result += 'empty';
+  } else {
+    result += workflow.workflowInfo().rootWorkflow!.workflowId;
+  }
+  if (!workflow.workflowInfo().parent) {
+    result += ' ';
+    result += await workflow.executeChild(rootWorkflow, { args: [] });
+  }
+  return result;
+}
+
+test('Workflow can return root workflow', async (t) => {
+  const { createWorker, startWorkflow } = helpers(t);
+  const worker = await createWorker();
+  await worker.runUntil(async () => {
+    const handle = await startWorkflow(rootWorkflow, { workflowId: 'test-root-workflow-length', args: [] });
+    const result = await handle.result();
+    t.deepEqual(result, 'empty test-root-workflow-length');
+  });
+});
+
 export async function upsertAndReadMemo(memo: Record<string, unknown>): Promise<Record<string, unknown> | undefined> {
   workflow.upsertMemo(memo);
   return workflow.workflowInfo().memo;

packages/worker/src/utils.ts

@@ -1,5 +1,5 @@
-import type { coresdk } from '@temporalio/proto';
-import { IllegalStateError, ParentWorkflowInfo } from '@temporalio/workflow';
+import type { coresdk, temporal } from '@temporalio/proto';
+import { IllegalStateError, ParentWorkflowInfo, RootWorkflowInfo } from '@temporalio/workflow';
 
 export const MiB = 1024 ** 2;
 
@@ -28,3 +28,20 @@ export function convertToParentWorkflowType(
     namespace: parent.namespace,
   };
 }
+
+export function convertToRootWorkflowType(
+  root: temporal.api.common.v1.IWorkflowExecution | null | undefined
+): RootWorkflowInfo | undefined {
+  if (!root) {
+    return undefined;
+  }
+
+  if (!root.workflowId || !root.runId) {
+    throw new IllegalStateError('Root IWorkflowExecution is missing a field that should be defined');
+  }
+
+  return {
+    workflowId: root.workflowId,
+    runId: root.runId,
+  };
+}

packages/worker/src/worker.ts

@@ -71,7 +71,7 @@ import {
 } from './replay';
 import { History, Runtime } from './runtime';
 import { CloseableGroupedObservable, closeableGroupBy, mapWithState, mergeMapWithState } from './rxutils';
-import { byteArrayToBuffer, convertToParentWorkflowType } from './utils';
+import { byteArrayToBuffer, convertToParentWorkflowType, convertToRootWorkflowType } from './utils';
 import {
   CompiledWorkerOptions,
   CompiledWorkerOptionsWithBuildId,
@@ -1270,6 +1270,7 @@ export class Worker {
       workflowExecutionExpirationTime,
       cronScheduleToScheduleInterval,
       priority,
+      rootWorkflow,
     } = initWorkflowJob;
 
     // Note that we can't do payload convertion here, as there's no guarantee that converted payloads would be safe to
@@ -1307,6 +1308,7 @@ export class Worker {
         isReplaying: activation.isReplaying,
       },
       priority: decodePriority(priority),
+      rootWorkflow: convertToRootWorkflowType(rootWorkflow),
     };
     const logAttributes = workflowLogAttributes(workflowInfo);
     this.logger.trace('Creating workflow', logAttributes);

packages/workflow/src/index.ts

@@ -92,6 +92,7 @@ export {
   ContinueAsNew,
   ContinueAsNewOptions,
   EnhancedStackTrace,
+  RootWorkflowInfo,
   StackTraceFileLocation,
   StackTraceFileSlice,
   ParentClosePolicy,

packages/workflow/src/interfaces.ts

@@ -189,6 +189,22 @@ export interface WorkflowInfo {
    * Priority of this workflow
    */
   readonly priority?: Priority;
+
+  /**
+   * The root workflow execution, defined as follows:
+   * 1. A workflow without a parent workflow is its own root workflow.
+   * 2. A workflow with a parent workflow has the same root workflow as
+   * its parent.
+   *
+   * When there is no parent workflow, i.e., the workflow is its own root workflow,
+   * this field is `undefined`.
+   *
+   * Note that Continue-as-New (or reset) propagates the workflow parentage relationship,
+   * and therefore, whether the new workflow has the same root workflow as the original one
+   * depends on whether it had a parent.
+   *
+   */
+  readonly rootWorkflow?: RootWorkflowInfo;
 }
 
 /**
@@ -229,6 +245,11 @@ export interface ParentWorkflowInfo {
   namespace: string;
 }
 
+export interface RootWorkflowInfo {
+  workflowId: string;
+  runId: string;
+}
+
 /**
  * Not an actual error, used by the Workflow runtime to abort execution when {@link continueAsNew} is called
  */