refactor: debounce writing to disk

apps/server/src/api-data/rundown/rundown.dao.ts

@@ -108,11 +108,6 @@ export function createTransaction(options: TransactionOptions): Transaction {
   function commit(shouldProcess: boolean = true) {
     // if the rundown is mutable we persist the changes
     if (options.mutableRundown) {
-      // schedule a database update
-      setImmediate(async () => {
-        await getDataProvider().setRundown(cachedRundown.id, cachedRundown);
-      });
-
       // update fields which are agnostic of whether the rundown is processed
       cachedRundown.revision = cachedRundown.revision + 1;
       cachedRundown.title = rundown.title;
@@ -133,16 +128,17 @@ export function createTransaction(options: TransactionOptions): Transaction {
         cachedRundown.flatOrder = metadata.flatEntryOrder;
         rundownMetadata = metadata;
       }
+
+      // persist after all mutations are applied
+      getDataProvider().setRundown(cachedRundown.id, cachedRundown);
     }
 
     // if the customFields are mutable we persist the changes
     if (options.mutableCustomFields) {
-      // schedule a database update
-      setImmediate(async () => {
-        await getDataProvider().setCustomFields(projectCustomFields);
-      });
-
       projectCustomFields = customFields;
+
+      // persist after reassignment
+      getDataProvider().setCustomFields(projectCustomFields);
     }
 
     return {
@@ -552,10 +548,8 @@ export const rundownMutation = {
 /**
  * Exposes a way to update a rundown which is not active
  */
-export function updateBackgroundRundown(rundownId: string, rundown: Rundown) {
+export async function updateBackgroundRundown(rundownId: string, rundown: Rundown) {
-  setImmediate(async () => {
+  await getDataProvider().setRundown(rundownId, rundown);
-    await getDataProvider().setRundown(rundownId, rundown);
-  });
 }
 
 /**
@@ -652,9 +646,7 @@ export function init(initialRundown: Readonly<Rundown>, initialCustomFields: Rea
   rundownMetadata = metadata;
 
   // defer writing to the database
-  setImmediate(async () => {
+  getDataProvider().setRundown(cachedRundown.id, cachedRundown);
-    await getDataProvider().setRundown(cachedRundown.id, cachedRundown);
-  });
 
   return { rundown, rundownMetadata, customFields, revision: rundown.revision };
 }

apps/server/src/api-data/rundown/rundown.service.ts

@@ -486,7 +486,7 @@ export async function editCustomField(
       if (rundownId !== rundown.id) {
         const backgroundRundown = structuredClone(projectRundowns[rundownId]);
         customFieldMutation.renameUsages(backgroundRundown, oldKey, newKey);
-        updateBackgroundRundown(rundownId, backgroundRundown);
+        await updateBackgroundRundown(rundownId, backgroundRundown);
       }
     }
 
@@ -526,7 +526,7 @@ export async function deleteCustomField(key: CustomFieldKey, projectRundowns: Pr
     if (rundownId !== rundown.id) {
       const backgroundRundown = structuredClone(projectRundowns[rundownId]);
       customFieldMutation.removeUsages(backgroundRundown, key);
-      updateBackgroundRundown(rundownId, backgroundRundown);
+      await updateBackgroundRundown(rundownId, backgroundRundown);
     }
   }
 

apps/server/src/app.ts

@@ -25,7 +25,7 @@ import { integrationRouter } from './api-integration/integration.router.js';
 
 // Import adapters
 import { socket } from './adapters/WebsocketAdapter.js';
-import { getDataProvider } from './classes/data-provider/DataProvider.js';
+import { getDataProvider, flushPendingWrites } from './classes/data-provider/DataProvider.js';
 
 // Services
 import { logger } from './classes/Logger.js';
@@ -266,6 +266,10 @@ export const startIntegrations = async () => {
 export const shutdown = async (exitCode = 0) => {
   consoleHighlight(`Ontime shutting down with code ${exitCode}`);
 
+  await flushPendingWrites().catch((_error) => {
+    /** nothing do to here */
+  });
+
   // clear the restore file if it was a normal exit
   // 0 means it was a SIGNAL
   // 1 means crash -> keep the file

apps/server/src/classes/data-provider/DataProvider.ts

@@ -180,10 +180,58 @@ async function mergeIntoData(newData: Partial<DatabaseModel>): ReadonlyPromise<D
   return db.data;
 }
 
+// Module-level state for debounced writes
+let pendingWrite: NodeJS.Timeout | null = null;
+let activeWrite: Promise<void> | null = null;
+const writeDelayMs = 3000; // 3 seconds
+
 /**
- * Handles persisting data to file
+ * Handles persisting data to file with trailing-edge debounce
+ * Multiple rapid calls will be coalesced into a single write
  */
 async function persist() {
   if (isTest) return;
+
+  // Cancel any pending write and reschedule
+  if (pendingWrite) {
+    clearTimeout(pendingWrite);
+  }
+
+  // Schedule new write after quiet period
+  pendingWrite = setTimeout(async () => {
+    pendingWrite = null;
+
+    // Wait for any in-progress write to finish first
+    if (activeWrite) {
+      await activeWrite;
+    }
+
+    try {
+      activeWrite = db.write();
+      await activeWrite;
+    } catch (error) {
+      console.error('Failed to persist database:', error);
+    } finally {
+      activeWrite = null;
+    }
+  }, writeDelayMs);
+}
+
+/**
+ * Force immediate write of any pending changes
+ */
+export async function flushPendingWrites() {
+  if (isTest) return;
+
+  if (pendingWrite) {
+    clearTimeout(pendingWrite);
+    pendingWrite = null;
+  }
+
+  // Wait for any in-progress write to finish
+  if (activeWrite) {
+    await activeWrite;
+  }
+
   await db.write();
 }