fix: useEventBus by propagating config to DefaultEventsService

This setting was added by reading from an optional `config` argument.
This was never passed, so `auto` was always assumed.
https://github.com/backstage/backstage/pull/27227/files#diff-cffd40a187b4fc584f03c968517fbacc110bde6a467f2384bbd92b803d3db47eR374-R379

Signed-off-by: RedlineTriad <39059512+RedlineTriad@users.noreply.github.com>

.changeset/itchy-elephants-trade.md

@@ -0,0 +1,6 @@
+---
+'@backstage/plugin-events-backend': patch
+'@backstage/plugin-events-node': patch
+---
+
+Fix `events.useEventBus` by propagating config to `DefaultEventsService`

packages/backend-legacy/src/index.ts

@@ -73,9 +73,10 @@ function makeCreateEnv(config: Config) {
     discovery,
   });
 
-  const eventsService = DefaultEventsService.create({ logger: root });
+  const eventsService = DefaultEventsService.create({ logger: root, config });
   const eventBroker = new DefaultEventBroker(
     root.child({ type: 'plugin' }),
+    config,
     eventsService,
   );
   const signalsService = DefaultSignalsService.create({

plugins/events-backend/report.api.md

@@ -18,7 +18,7 @@ import { LoggerService } from '@backstage/backend-plugin-api';
 // @public @deprecated
 export class DefaultEventBroker implements EventBroker {
   // @deprecated
-  constructor(logger: LoggerService, events?: EventsService);
+  constructor(logger: LoggerService, config?: Config, events?: EventsService);
   // (undocumented)
   publish(params: EventParams): Promise<void>;
   // (undocumented)
@@ -29,7 +29,7 @@ export class DefaultEventBroker implements EventBroker {
 
 // @public @deprecated
 export class EventsBackend {
-  constructor(logger: Logger);
+  constructor(logger: Logger, config?: Config);
   // (undocumented)
   addPublishers(
     ...publishers: Array<EventPublisher | Array<EventPublisher>>

plugins/events-backend/src/service/DefaultEventBroker.ts

@@ -15,6 +15,7 @@
  */
 
 import { LoggerService } from '@backstage/backend-plugin-api';
+import { Config } from '@backstage/config';
 import {
   DefaultEventsService,
   EventBroker,
@@ -41,8 +42,8 @@ export class DefaultEventBroker implements EventBroker {
    * An instance can be passed (required for a mixed mode), otherwise a new instance gets created internally.
    * @deprecated use `DefaultEventsService` directly instead
    */
-  constructor(logger: LoggerService, events?: EventsService) {
-    this.events = events ?? DefaultEventsService.create({ logger });
+  constructor(logger: LoggerService, config?: Config, events?: EventsService) {
+    this.events = events ?? DefaultEventsService.create({ logger, config });
   }
 
   async publish(params: EventParams): Promise<void> {

plugins/events-backend/src/service/EventsBackend.ts

@@ -21,6 +21,7 @@ import {
 } from '@backstage/plugin-events-node';
 import { Logger } from 'winston';
 import { DefaultEventBroker } from './DefaultEventBroker';
+import { Config } from '@backstage/config';
 
 /**
  * A builder that helps wire up all component parts of the event management.
@@ -33,8 +34,8 @@ export class EventsBackend {
   private publishers: EventPublisher[] = [];
   private subscribers: EventSubscriber[] = [];
 
-  constructor(logger: Logger) {
-    this.eventBroker = new DefaultEventBroker(logger);
+  constructor(logger: Logger, config?: Config) {
+    this.eventBroker = new DefaultEventBroker(logger, config);
   }
 
   setEventBroker(eventBroker: EventBroker): EventsBackend {

plugins/events-node/README.md

@@ -27,7 +27,7 @@ import { DefaultEventsService } from '@backstage/plugin-events-node';
 
 function makeCreateEnv(config: Config) {
   // ...
-  const eventsService = DefaultEventsService.create({ logger: root });
+  const eventsService = DefaultEventsService.create({ logger: root, config });
   // ...
   return (plugin: string): PluginEnvironment => {
     // ...

plugins/events-node/src/service.ts

@@ -42,9 +42,10 @@ export const eventsServiceFactory = createServiceFactory({
     logger: coreServices.logger,
     lifecycle: coreServices.lifecycle,
     auth: coreServices.auth,
+    config: coreServices.rootConfig,
   },
-  async createRootContext({ rootLogger }) {
-    return DefaultEventsService.create({ logger: rootLogger });
+  async createRootContext({ rootLogger, config }) {
+    return DefaultEventsService.create({ logger: rootLogger, config });
   },
   async factory(
     { pluginMetadata, discovery, logger, lifecycle, auth },