✨ Add support for "_FILE" environment variables

packages/cli/src/GenericHelpers.ts

@@ -1,6 +1,12 @@
 import * as config from '../config';
 import * as express from 'express';
+import {
+	readFile as fsReadFile,
+} from 'fs';
+import { promisify } from "util";
+import { IDataObject } from 'n8n-workflow';
 
+const fsReadFileAsync = promisify(fsReadFile);
 
 /**
  * Displays a message to the user
@@ -46,3 +52,54 @@ export function getBaseUrl(): string {
 export function getSessionId(req: express.Request): string | undefined {
 	return req.headers.sessionid as string | undefined;
 }
+
+
+/**
+ * Gets value from config with support for "_FILE" environment variables
+ *
+ * @export
+ * @param {string} configKey The key of the config data to get
+ * @returns {(Promise<string | boolean | number | undefined>)}
+ */
+export async function getConfigValue(configKey: string): Promise<string | boolean | number | undefined> {
+	const configKeyParts = configKey.split('.');
+
+	// Get the environment variable
+	const configSchema = config.getSchema();
+	let currentSchema = configSchema.properties as IDataObject;
+	for (const key of configKeyParts) {
+		if (currentSchema[key] === undefined) {
+			throw new Error(`Key "${key}" of ConfigKey "${configKey}" does not exist`);
+		} else if ((currentSchema[key]! as IDataObject).properties === undefined) {
+			currentSchema = currentSchema[key] as IDataObject;
+		} else {
+			currentSchema = (currentSchema[key] as IDataObject).properties as IDataObject;
+		}
+	}
+
+	// Check if environment variable is defined for config key
+	if (currentSchema.env === undefined) {
+		// No environment variable defined, so return value from config
+		return config.get(configKey);
+	}
+
+	// Check if special file enviroment variable exists
+	const fileEnvironmentVariable = process.env[currentSchema.env + '_FILE'];
+	if (fileEnvironmentVariable === undefined) {
+		// Does not exist, so return value from config
+		return config.get(configKey);
+	}
+
+	let data;
+	try {
+		data = await fsReadFileAsync(fileEnvironmentVariable, 'utf8') as string;
+	} catch (error) {
+		if (error.code === 'ENOENT') {
+			throw new Error(`The file "${fileEnvironmentVariable}" could not be found.`);
+		}
+
+		throw error;
+	}
+
+	return data;
+}