n8n/packages/nodes-base/nodes/ExecuteCommand.node.ts

import { IExecuteFunctions } from 'n8n-core';
import {
	INodeExecutionData,
	INodeType,
	INodeTypeDescription,
} from 'n8n-workflow';

import { exec } from 'child_process';


export interface IExecReturnData {
	exitCode: number;
	error?: Error;
	stderr: string;
	stdout: string;
}


/**
 * Promisifiy exec manually to also get the exit code
 *
 * @param {string} command
 * @returns {Promise<IExecReturnData>}
 */
function execPromise(command: string): Promise<IExecReturnData> {
	const returnData: IExecReturnData = {
		exitCode: 0,
		stderr: '',
		stdout: '',
	};

	return new Promise((resolve, reject) => {
		exec(command, { cwd: process.cwd() }, (error, stdout, stderr) => {
			returnData.stdout = stdout.trim();
			returnData.stderr = stderr.trim();

			if (error) {
				returnData.error = error;
			}

			resolve(returnData);
		}).on('exit', code => { returnData.exitCode = code || 0; });
	});
}


export class ExecuteCommand implements INodeType {
	description: INodeTypeDescription = {
		displayName: 'Execute Command',
		name: 'executeCommand',
		icon: 'fa:terminal',
		group: ['transform'],
		version: 1,
		description: 'Executes a command on the host.',
		defaults: {
			name: 'Execute Command',
			color: '#886644',
		},
		inputs: ['main'],
		outputs: ['main'],
		properties: [
			{
				displayName: 'Execute Once',
				name: 'executeOnce',
				type: 'boolean',
				default: true,
				description: 'If activated it executes only once instead of once for each entry.',
			},
			{
				displayName: 'Command',
				name: 'command',
				typeOptions: {
					rows: 5,
				},
				type: 'string',
				default: '',
				placeholder: 'echo "test"',
				description: 'The command to execute',
			},
		]
	};


	async execute(this: IExecuteFunctions): Promise<INodeExecutionData[][]> {

		let items = this.getInputData();

		let command: string;
		const executeOnce = this.getNodeParameter('executeOnce', 0) as boolean;

		if (executeOnce === true) {
			items = [items[0]];
		}

		let item: INodeExecutionData;
		for (let itemIndex = 0; itemIndex < items.length; itemIndex++) {
			item = items[itemIndex];

			command = this.getNodeParameter('command', itemIndex) as string;

			const {
				// error, TODO: Later make it possible to select if it should fail on error or not
				exitCode,
				stdout,
				stderr,
			} = await execPromise(command);

			item.json = {
				exitCode,
				stderr,
				stdout,
			};
		}

		return this.prepareOutputData(items);
	}
}