ux: Warn on invalid device name when trying to start a service

Device names with newlines cause reboot loops, due to newlines not being
supported by docker. This PR will warn when a device name contains a
newline.

Change-type: patch
Signed-off-by: Cameron Diver <cameron@resin.io>

src/compose/service-manager.coffee

@@ -5,7 +5,7 @@ JSONStream = require 'JSONStream'
 fs = Promise.promisifyAll(require('fs'))
 
 logTypes = require '../lib/log-types'
-{ checkInt } = require '../lib/validation'
+{ checkInt, isValidDeviceName } = require '../lib/validation'
 constants = require '../lib/constants'
 
 Service = require './service'
@@ -103,6 +103,11 @@ module.exports = class ServiceManager extends EventEmitter
 
 			@config.get('name')
 			.then (deviceName) =>
+				if !isValidDeviceName(deviceName)
+					throw new Error(
+						'The device name contains a newline, which is unsupported by balena. ' +
+						'Please fix the device name.'
+					)
 
 				service.environment['RESIN_DEVICE_NAME_AT_INIT'] = deviceName
 

src/lib/validation.ts

@@ -154,6 +154,15 @@ export function isValidLabelsObject(obj: LabelObject): boolean {
 	});
 }
 
+export function isValidDeviceName(name: string): boolean {
+	// currently the only disallowed value in a device name is a newline
+	const newline = name.indexOf('\n') !== -1;
+	if (newline) {
+		console.log('debug: newline found in device name. This is invalid and should be removed');
+	}
+	return !newline;
+}
+
 function undefinedOrValidEnv(val: EnvVarObject): boolean {
 	return val == null || isValidEnv(val);
 }