From 9b1109858c6c234e0ea353b6cf5001226e6ad01f Mon Sep 17 00:00:00 2001
From: Camila Belo <camilaibs@gmail.com>
Date: Tue, 22 Nov 2022 11:09:07 +0100
Subject: [PATCH 1/2] fix(search-backend-node): max listeners exceeded warning

Signed-off-by: Camila Belo <camilaibs@gmail.com>
---
 .changeset/heavy-frogs-confess.md             |  5 +++
 .../search-backend-node/src/Scheduler.test.ts | 36 +++++++++++++++++++
 plugins/search-backend-node/src/Scheduler.ts  | 13 ++++---
 3 files changed, 50 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/heavy-frogs-confess.md

diff --git a/.changeset/heavy-frogs-confess.md b/.changeset/heavy-frogs-confess.md
new file mode 100644
index 0000000000..3a7c53f4e5
--- /dev/null
+++ b/.changeset/heavy-frogs-confess.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-search-backend-node': patch
+---
+
+Fix the scheduler "max listeners exceeded" warning by having "abort controllers" per task instead of having a single one for all tasks (previously we used the same controller for all collators, logging the warning every time we had more than 10 collators running in parallel).
diff --git a/plugins/search-backend-node/src/Scheduler.test.ts b/plugins/search-backend-node/src/Scheduler.test.ts
index 30e5c7e416..6daae3013d 100644
--- a/plugins/search-backend-node/src/Scheduler.test.ts
+++ b/plugins/search-backend-node/src/Scheduler.test.ts
@@ -204,4 +204,40 @@ describe('Scheduler', () => {
       );
     });
   });
+
+  describe('stop', () => {
+    it('should abort tasks on stop', () => {
+      const run = jest.fn();
+
+      // Add tasks and interval to schedule
+      testScheduler.addToSchedule({
+        id: '1',
+        task: jest.fn(),
+        scheduledRunner: { run },
+      });
+      testScheduler.addToSchedule({
+        id: '2',
+        task: jest.fn(),
+        scheduledRunner: { run },
+      });
+
+      // Starts scheduling process
+      testScheduler.start();
+
+      const signals = run.mock.calls.map(([options]) => options.signal);
+
+      expect(signals).toHaveLength(2);
+
+      for (const signal of signals) {
+        expect(signal.aborted).toBeFalsy();
+      }
+
+      // Stops scheduling process
+      testScheduler.stop();
+
+      for (const signal of signals) {
+        expect(signal.aborted).toBeTruthy();
+      }
+    });
+  });
 });
diff --git a/plugins/search-backend-node/src/Scheduler.ts b/plugins/search-backend-node/src/Scheduler.ts
index 872a410808..82d45df090 100644
--- a/plugins/search-backend-node/src/Scheduler.ts
+++ b/plugins/search-backend-node/src/Scheduler.ts
@@ -40,13 +40,13 @@ export type ScheduleTaskParameters = {
 export class Scheduler {
   private logger: Logger;
   private schedule: { [id: string]: TaskEnvelope };
-  private abortController: AbortController;
+  private abortControllers: AbortController[];
   private isRunning: boolean;
 
   constructor(options: { logger: Logger }) {
     this.logger = options.logger;
     this.schedule = {};
-    this.abortController = new AbortController();
+    this.abortControllers = [];
     this.isRunning = false;
   }
 
@@ -78,11 +78,13 @@ export class Scheduler {
     this.logger.info('Starting all scheduled search tasks.');
     this.isRunning = true;
     Object.keys(this.schedule).forEach(id => {
+      const abortController = new AbortController();
+      this.abortControllers.push(abortController);
       const { task, scheduledRunner } = this.schedule[id];
       scheduledRunner.run({
         id,
         fn: task,
-        signal: this.abortController.signal,
+        signal: abortController.signal,
       });
     });
   }
@@ -92,7 +94,10 @@ export class Scheduler {
    */
   stop() {
     this.logger.info('Stopping all scheduled search tasks.');
-    this.abortController.abort();
+    for (const abortController of this.abortControllers) {
+      abortController.abort();
+    }
+    this.abortControllers = [];
     this.isRunning = false;
   }
 }

From 683ced83f663f9f4643901ea9a339117984f1536 Mon Sep 17 00:00:00 2001
From: Camila Belo <camilaibs@gmail.com>
Date: Tue, 22 Nov 2022 12:33:27 +0100
Subject: [PATCH 2/2] apply review suggestions

Signed-off-by: Camila Belo <camilaibs@gmail.com>
---
 .changeset/heavy-frogs-confess.md        | 5 -----
 .changeset/search-heavy-frogs-confess.md | 5 +++++
 2 files changed, 5 insertions(+), 5 deletions(-)
 delete mode 100644 .changeset/heavy-frogs-confess.md
 create mode 100644 .changeset/search-heavy-frogs-confess.md

diff --git a/.changeset/heavy-frogs-confess.md b/.changeset/heavy-frogs-confess.md
deleted file mode 100644
index 3a7c53f4e5..0000000000
--- a/.changeset/heavy-frogs-confess.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'@backstage/plugin-search-backend-node': patch
----
-
-Fix the scheduler "max listeners exceeded" warning by having "abort controllers" per task instead of having a single one for all tasks (previously we used the same controller for all collators, logging the warning every time we had more than 10 collators running in parallel).
diff --git a/.changeset/search-heavy-frogs-confess.md b/.changeset/search-heavy-frogs-confess.md
new file mode 100644
index 0000000000..a37c28c60c
--- /dev/null
+++ b/.changeset/search-heavy-frogs-confess.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-search-backend-node': patch
+---
+
+Fixed a bug that could cause a `max listeners exceeded warning` to be logged when more than 10 collators were running simultaneously.