feat(core): Support executing single nodes not part of a graph as a partial execution (#13529)

packages/core/src/execution-engine/__tests__/workflow-execute.test.ts

@@ -52,6 +52,10 @@ import { WorkflowExecute } from '../workflow-execute';
 
 const nodeTypes = Helpers.NodeTypes();
 
+beforeEach(() => {
+	jest.resetAllMocks();
+});
+
 describe('WorkflowExecute', () => {
 	describe('v0 execution order', () => {
 		const tests: WorkflowTestData[] = legacyWorkflowExecuteTests;
@@ -455,6 +459,56 @@ describe('WorkflowExecute', () => {
 				new Set([node1]),
 			);
 		});
+
+		//                 ►►
+		//                ┌──────┐
+		//                │orphan│
+		//                └──────┘
+		//  ┌───────┐     ┌───────────┐
+		//  │trigger├────►│destination│
+		//  └───────┘     └───────────┘
+		test('works with a single node', async () => {
+			// ARRANGE
+			const waitPromise = createDeferredPromise<IRun>();
+			const nodeExecutionOrder: string[] = [];
+			const additionalData = Helpers.WorkflowExecuteAdditionalData(waitPromise, nodeExecutionOrder);
+			const workflowExecute = new WorkflowExecute(additionalData, 'manual');
+
+			const trigger = createNodeData({ name: 'trigger' });
+			const destination = createNodeData({ name: 'destination' });
+			const orphan = createNodeData({ name: 'orphan' });
+
+			const workflow = new DirectedGraph()
+				.addNodes(trigger, destination, orphan)
+				.addConnections({ from: trigger, to: destination })
+				.toWorkflow({ name: '', active: false, nodeTypes });
+
+			const pinData: IPinData = {};
+			const runData: IRunData = {
+				[trigger.name]: [toITaskData([{ data: { value: 1 } }])],
+				[destination.name]: [toITaskData([{ data: { nodeName: destination.name } }])],
+			};
+			const dirtyNodeNames: string[] = [];
+
+			const processRunExecutionDataSpy = jest
+				.spyOn(workflowExecute, 'processRunExecutionData')
+				.mockImplementationOnce(jest.fn());
+
+			// ACT
+			await workflowExecute.runPartialWorkflow2(
+				workflow,
+				runData,
+				pinData,
+				dirtyNodeNames,
+				orphan.name,
+			);
+
+			// ASSERT
+			expect(processRunExecutionDataSpy).toHaveBeenCalledTimes(1);
+			expect(processRunExecutionDataSpy).toHaveBeenCalledWith(
+				new DirectedGraph().addNode(orphan).toWorkflow({ ...workflow }),
+			);
+		});
 	});
 
 	describe('checkReadyForExecution', () => {
@@ -465,6 +519,8 @@ describe('WorkflowExecute', () => {
 		const nodeParamIssuesSpy = jest.spyOn(NodeHelpers, 'getNodeParametersIssues');
 
 		const nodeTypes = mock<INodeTypes>();
+
+		beforeEach(() => {
 			nodeTypes.getByNameAndVersion.mockImplementation((type) => {
 				// TODO: getByNameAndVersion signature needs to be updated to allow returning undefined
 				if (type === 'unknownNode') return undefined as unknown as INodeType;
@@ -474,10 +530,9 @@ describe('WorkflowExecute', () => {
 					},
 				});
 			});
+		});
 		const workflowExecute = new WorkflowExecute(mock(), 'manual');
 
-		beforeEach(() => jest.clearAllMocks());
-
 		it('should return null if there are no nodes', () => {
 			const workflow = new Workflow({
 				nodes: [],
@@ -562,7 +617,9 @@ describe('WorkflowExecute', () => {
 			},
 		});
 
+		beforeEach(() => {
 			nodeTypes.getByNameAndVersion.mockReturnValue(triggerNodeType);
+		});
 
 		const workflow = new Workflow({
 			nodeTypes,

packages/core/src/execution-engine/partial-execution-utils/__tests__/find-subgraph.test.ts

@@ -33,6 +33,27 @@ describe('findSubgraph', () => {
 		expect(subgraph).toEqual(graph);
 	});
 
+	//                 ►►
+	//                ┌──────┐
+	//                │orphan│
+	//                └──────┘
+	//  ┌───────┐     ┌───────────┐
+	//  │trigger├────►│destination│
+	//  └───────┘     └───────────┘
+	test('works with a single node', () => {
+		const trigger = createNodeData({ name: 'trigger' });
+		const destination = createNodeData({ name: 'destination' });
+		const orphan = createNodeData({ name: 'orphan' });
+
+		const graph = new DirectedGraph()
+			.addNodes(trigger, destination, orphan)
+			.addConnections({ from: trigger, to: destination });
+
+		const subgraph = findSubgraph({ graph, destination: orphan, trigger: orphan });
+
+		expect(subgraph).toEqual(new DirectedGraph().addNode(orphan));
+	});
+
 	//                     ►►
 	//  ┌───────┐         ┌───────────┐
 	//  │       ├────────►│           │

packages/core/src/execution-engine/partial-execution-utils/find-subgraph.ts

@@ -13,6 +13,12 @@ function findSubgraphRecursive(
 ) {
 	// If the current node is the chosen trigger keep this branch.
 	if (current === trigger) {
+		// If this graph consists of only one node there won't be any connections
+		// and the loop below won't add anything.
+		// We're adding the trigger here so that graphs with one node and no
+		// connections are handled correctly.
+		newGraph.addNode(trigger);
+
 		for (const connection of currentBranch) {
 			newGraph.addNodes(connection.from, connection.to);
 			newGraph.addConnection(connection);

packages/core/src/execution-engine/workflow-execute.ts

@@ -354,16 +354,52 @@ export class WorkflowExecute {
 			`Could not find a node with the name ${destinationNodeName} in the workflow.`,
 		);
 
+		let graph = DirectedGraph.fromWorkflow(workflow);
+
+		// Edge Case 1:
+		// Support executing a single node that is not connected to a trigger
+		const destinationHasNoParents = graph.getDirectParentConnections(destination).length === 0;
+		if (destinationHasNoParents) {
+			// short cut here, only create a subgraph and the stacks
+			graph = findSubgraph({
+				graph: filterDisabledNodes(graph),
+				destination,
+				trigger: destination,
+			});
+			const filteredNodes = graph.getNodes();
+			runData = cleanRunData(runData, graph, new Set([destination]));
+			const { nodeExecutionStack, waitingExecution, waitingExecutionSource } =
+				recreateNodeExecutionStack(graph, new Set([destination]), runData, pinData ?? {});
+
+			this.status = 'running';
+			this.runExecutionData = {
+				startData: {
+					destinationNode: destinationNodeName,
+					runNodeFilter: Array.from(filteredNodes.values()).map((node) => node.name),
+				},
+				resultData: {
+					runData,
+					pinData,
+				},
+				executionData: {
+					contextData: {},
+					nodeExecutionStack,
+					metadata: {},
+					waitingExecution,
+					waitingExecutionSource,
+				},
+			};
+
+			return this.processRunExecutionData(graph.toWorkflow({ ...workflow }));
+		}
+
 		// 1. Find the Trigger
 		const trigger = findTriggerForPartialExecution(workflow, destinationNodeName);
 		if (trigger === undefined) {
-			throw new ApplicationError(
-				'The destination node is not connected to any trigger. Partial executions need a trigger.',
-			);
+			throw new ApplicationError('Connect a trigger to run this node');
 		}
 
 		// 2. Find the Subgraph
-		let graph = DirectedGraph.fromWorkflow(workflow);
 		graph = findSubgraph({ graph: filterDisabledNodes(graph), destination, trigger });
 		const filteredNodes = graph.getNodes();
 
@@ -380,7 +416,7 @@ export class WorkflowExecute {
 
 		// 7. Recreate Execution Stack
 		const { nodeExecutionStack, waitingExecution, waitingExecutionSource } =
-			recreateNodeExecutionStack(graph, new Set(startNodes), runData, pinData ?? {});
+			recreateNodeExecutionStack(graph, startNodes, runData, pinData ?? {});
 
 		// 8. Execute
 		this.status = 'running';