feat(events): Implement default priority-based event processing (#14476)

* feat(events): Set internal events default priority to lowest, default events to 100 and order placed to 10

* Create swift-months-rush.md

* improvements

* improvements

* improvements

* fix condition

* doc

* fix tests

* fix tests

---------

Co-authored-by: Oli Juhl <59018053+olivermrbl@users.noreply.github.com>

packages/core/core-flows/src/cart/workflows/complete-cart.ts

@@ -6,6 +6,7 @@ import {
   UsageComputedActions,
 } from "@medusajs/framework/types"
 import {
+  EventPriority,
   isDefined,
   Modules,
   OrderStatus,
@@ -598,6 +599,9 @@ export const completeCartWorkflow = createWorkflow(
         emitEventStep({
           eventName: OrderWorkflowEvents.PLACED,
           data: { id: createdOrder.id },
+          options: {
+            priority: EventPriority.CRITICAL,
+          },
         })
       )
 

packages/core/core-flows/src/draft-order/workflows/convert-draft-order.ts

@@ -1,4 +1,5 @@
 import {
+  EventPriority,
   Modules,
   OrderStatus,
   OrderWorkflowEvents,
@@ -180,6 +181,9 @@ export const convertDraftOrderWorkflow = createWorkflow(
       emitEventStep({
         eventName: OrderWorkflowEvents.PLACED,
         data: { id: updatedOrder.id },
+        options: {
+          priority: EventPriority.CRITICAL,
+        },
       })
     )
 

packages/core/utils/src/event-bus/utils.ts

@@ -87,3 +87,15 @@ export function buildEventNamesFromEntityName<TNames extends string[]>(
 
   return events as ReturnType<TNames>
 }
+
+export const EventPriority = {
+  CRITICAL: 10,
+  HIGH: 50,
+  DEFAULT: 100,
+  LOW: 500,
+  /**
+   * Lowest priority value supported by BullMQ (2^21)
+   * Internal events use this priority to ensure they don't block critical business events
+   */
+  LOWEST: 2_097_152,
+} as const