make sure only a single instance of the server is the schedule executor

apps/api/src/schedule/index.ts

@@ -12,6 +12,7 @@ import * as yjs from '../yjs/v2/index.js'
 import { AppPersistor } from '../yjs/v2/persistors.js'
 import { ExecutionQueue } from '@briefer/editor'
 import { updateAppState } from '../yjs/v2/documents.js'
+import { acquireLock } from '../lock.js'
 
 function convertToCron(schedule: ExecutionSchedule): string {
   switch (schedule.type) {
@@ -199,19 +200,37 @@ export async function runSchedule(socketServer: IOServer) {
 
   let stop = false
   const loop = new Promise<void>(async (resolve) => {
-    while (true) {
-      try {
-        await updateSchedule()
-      } catch (err) {
-        logger().error({ err, module: 'schedule' }, 'Failed to update schedule')
-      }
-
+    logger().trace('Acquiring lock to be the schedule executor')
+    await acquireLock('schedule-executor', async () => {
       if (stop) {
-        break
+        logger().trace(
+          'Schedule executor lock acquired but server is shutting down'
+        )
+        return
       }
 
-      await new Promise((resolve) => setTimeout(resolve, 5000))
-    }
+      logger().trace('Schedule executor lock acquired')
+      while (true) {
+        if (stop) {
+          break
+        }
+
+        try {
+          await updateSchedule()
+        } catch (err) {
+          logger().error(
+            { err, module: 'schedule' },
+            'Failed to update schedule'
+          )
+        }
+
+        if (stop) {
+          break
+        }
+
+        await new Promise((resolve) => setTimeout(resolve, 5000))
+      }
+    })
 
     resolve()
   })