feat(workflows-sdk,orchestration): async step as background task (#6886)

packages/workflow-engine-inmemory/integration-tests/__fixtures__/index.ts

@@ -1,4 +1,5 @@
 export * from "./workflow_1"
 export * from "./workflow_2"
+export * from "./workflow_async"
 export * from "./workflow_step_timeout"
 export * from "./workflow_transaction_timeout"

packages/workflow-engine-inmemory/integration-tests/__fixtures__/workflow_async.ts

@@ -0,0 +1,29 @@
+import {
+  StepResponse,
+  createStep,
+  createWorkflow,
+} from "@medusajs/workflows-sdk"
+import { setTimeout } from "timers/promises"
+
+const step_1_background = createStep(
+  {
+    name: "step_1_background",
+    async: true,
+  },
+  jest.fn(async (input) => {
+    await setTimeout(200)
+
+    return new StepResponse(input)
+  })
+)
+
+createWorkflow(
+  {
+    name: "workflow_async_background",
+  },
+  function (input) {
+    const resp = step_1_background(input)
+
+    return resp
+  }
+)

packages/workflow-engine-inmemory/integration-tests/__tests__/index.spec.ts

@@ -5,8 +5,8 @@ import { IWorkflowEngineService } from "@medusajs/workflows-sdk"
 import { knex } from "knex"
 import { setTimeout } from "timers/promises"
 import "../__fixtures__"
-import { DB_URL, TestDatabase } from "../utils"
 import { workflow2Step2Invoke, workflow2Step3Invoke } from "../__fixtures__"
+import { DB_URL, TestDatabase } from "../utils"
 
 const sharedPgConnection = knex<any, any>({
   client: "pg",
@@ -172,5 +172,33 @@ describe("Workflow Orchestrator module", function () {
 
       expect(transaction.flow.state).toEqual("reverted")
     })
+
+    it("should subsctibe to a async workflow and receive the response when it finishes", (done) => {
+      const transactionId = "trx_123"
+
+      const onFinish = jest.fn(() => {
+        done()
+      })
+
+      void workflowOrcModule.subscribe({
+        workflowId: "workflow_async_background",
+        transactionId,
+        subscriber: (event) => {
+          if (event.eventType === "onFinish") {
+            onFinish()
+          }
+        },
+      })
+
+      void workflowOrcModule.run("workflow_async_background", {
+        input: {
+          myInput: "123",
+        },
+        transactionId,
+        throwOnError: false,
+      })
+
+      expect(onFinish).toHaveBeenCalledTimes(0)
+    })
   })
 })