perf(core): Optimize workflow activation errors (#8242)

At https://github.com/n8n-io/n8n/pull/8213 we introduced Redis hashes
for workflow ownership and manual webhooks...

- to remove clutter from multiple related keys at the top level,
- to improve performance by preventing serializing-deserializing, and
- to guarantee atomicity during concurrent updates in multi-main setup.

Workflow activation errors can also benefit from this. Added test
coverage as well.

To test manually, create a workflow with a trigger with an invalid
credential, edit the workflow's `active` column to `true`, and restart.
The activation error should show as a red triangle on canvas and in the
workflow list.

packages/cli/src/ActivationErrors.service.ts

@@ -1,10 +1,5 @@
 import { Service } from 'typedi';
 import { CacheService } from '@/services/cache/cache.service';
-import { jsonParse } from 'n8n-workflow';
-
-type ActivationErrors = {
-	[workflowId: string]: string; // error message
-};
 
 @Service()
 export class ActivationErrorsService {
@@ -12,38 +7,28 @@ export class ActivationErrorsService {
 
 	constructor(private readonly cacheService: CacheService) {}
 
-	async set(workflowId: string, errorMessage: string) {
+	async register(workflowId: string, errorMessage: string) {
-		const errors = await this.getAll();
+		await this.cacheService.setHash(this.cacheKey, { [workflowId]: errorMessage });
-
-		errors[workflowId] = errorMessage;
-
-		await this.cacheService.set(this.cacheKey, JSON.stringify(errors));
 	}
 
-	async unset(workflowId: string) {
+	async deregister(workflowId: string) {
-		const errors = await this.getAll();
+		await this.cacheService.deleteFromHash(this.cacheKey, workflowId);
-
-		if (Object.keys(errors).length === 0) return;
-
-		delete errors[workflowId];
-
-		await this.cacheService.set(this.cacheKey, JSON.stringify(errors));
 	}
 
 	async get(workflowId: string) {
-		const errors = await this.getAll();
+		const activationError = await this.cacheService.getHashValue<string>(this.cacheKey, workflowId);
 
-		if (Object.keys(errors).length === 0) return null;
+		if (!activationError) return null;
 
-		return errors[workflowId];
+		return activationError;
 	}
 
 	async getAll() {
-		const errors = await this.cacheService.get<string>(this.cacheKey);
+		const activationErrors = await this.cacheService.getHash<string>(this.cacheKey);
 
-		if (!errors) return {};
+		if (!activationErrors) return {};
 
-		return jsonParse<ActivationErrors>(errors);
+		return activationErrors;
 	}
 
 	async clearAll() {

packages/cli/src/ActiveWorkflowRunner.ts

@@ -425,7 +425,7 @@ export class ActiveWorkflowRunner {
 
 				void this.activeWorkflows.remove(workflowData.id);
 
-				void this.activationErrorsService.set(workflowData.id, error.message);
+				void this.activationErrorsService.register(workflowData.id, error.message);
 
 				// Run Error Workflow if defined
 				const activationError = new WorkflowActivationError(
@@ -630,13 +630,13 @@ export class ActiveWorkflowRunner {
 			// Workflow got now successfully activated so make sure nothing is left in the queue
 			this.removeQueuedWorkflowActivation(workflowId);
 
-			await this.activationErrorsService.unset(workflowId);
+			await this.activationErrorsService.deregister(workflowId);
 
 			const triggerCount = this.countTriggers(workflow, additionalData);
 			await this.workflowRepository.updateWorkflowTriggerCount(workflow.id, triggerCount);
 		} catch (e) {
 			const error = e instanceof Error ? e : new Error(`${e}`);
-			await this.activationErrorsService.set(workflowId, error.message);
+			await this.activationErrorsService.register(workflowId, error.message);
 
 			throw e;
 		}
@@ -757,7 +757,7 @@ export class ActiveWorkflowRunner {
 			);
 		}
 
-		await this.activationErrorsService.unset(workflowId);
+		await this.activationErrorsService.deregister(workflowId);
 
 		if (this.queuedActivations[workflowId] !== undefined) {
 			this.removeQueuedWorkflowActivation(workflowId);
@@ -824,6 +824,6 @@ export class ActiveWorkflowRunner {
 	}
 
 	async removeActivationError(workflowId: string) {
-		await this.activationErrorsService.unset(workflowId);
+		await this.activationErrorsService.deregister(workflowId);
 	}
 }

packages/cli/test/integration/activation-errors.service.test.ts

@@ -0,0 +1,87 @@
+import { ActivationErrorsService } from '@/ActivationErrors.service';
+import { CacheService } from '@/services/cache/cache.service';
+
+describe('ActivationErrorsService', () => {
+	const cacheService = new CacheService();
+	const activationErrorsService = new ActivationErrorsService(cacheService);
+
+	const firstWorkflowId = 'GSG0etbfTA2CNPDX';
+	const secondWorkflowId = 'k2ORscMPO66K0Jk3';
+
+	const firstErrorMsg = 'Failed to activate';
+	const secondErrorMsg = 'Also failed to activate';
+
+	afterEach(async () => {
+		await activationErrorsService.clearAll();
+	});
+
+	describe('register', () => {
+		test('should register an activation error for a workflow', async () => {
+			await activationErrorsService.register(firstWorkflowId, firstErrorMsg);
+
+			const activationError = await activationErrorsService.get(firstWorkflowId);
+
+			expect(activationError).toBe(firstErrorMsg);
+		});
+	});
+
+	describe('deregister', () => {
+		test('should deregister an activation error for a workflow', async () => {
+			await activationErrorsService.register(firstWorkflowId, firstErrorMsg);
+
+			await activationErrorsService.deregister(firstWorkflowId);
+
+			const activationError = await activationErrorsService.get(firstWorkflowId);
+
+			expect(activationError).toBeNull();
+		});
+	});
+
+	describe('get', () => {
+		test('should retrieve an activation error for a workflow', async () => {
+			await activationErrorsService.register(firstWorkflowId, firstErrorMsg);
+
+			const activationError = await activationErrorsService.get(firstWorkflowId);
+
+			expect(activationError).toBe(firstErrorMsg);
+		});
+
+		test('should return `null` if no activation error found for a workflow', async () => {
+			const activationError = await activationErrorsService.get(firstWorkflowId);
+
+			expect(activationError).toBeNull();
+		});
+	});
+
+	describe('getAll', () => {
+		test('should retrieve all activation errors', async () => {
+			await activationErrorsService.register(firstWorkflowId, firstErrorMsg);
+			await activationErrorsService.register(secondWorkflowId, secondErrorMsg);
+
+			const allActivationErrors = await activationErrorsService.getAll();
+
+			expect(allActivationErrors).toEqual({
+				[firstWorkflowId]: firstErrorMsg,
+				[secondWorkflowId]: secondErrorMsg,
+			});
+		});
+
+		test('should return an empty object if no activation errors', async () => {
+			const allActivationErrors = await activationErrorsService.getAll();
+
+			expect(allActivationErrors).toEqual({});
+		});
+	});
+
+	describe('clearAll()', () => {
+		test('should clear activation errors', async () => {
+			await activationErrorsService.register(firstWorkflowId, firstErrorMsg);
+			await activationErrorsService.register(secondWorkflowId, secondErrorMsg);
+
+			await activationErrorsService.clearAll();
+
+			const allActivationErrors = await activationErrorsService.getAll();
+			expect(allActivationErrors).toEqual({});
+		});
+	});
+});