Merge pull request #1497 from balena-io/1494-balena-socket

Mount docker socket under `/host/run` for services

src/compose/utils.ts

@@ -344,13 +344,19 @@ export async function addFeaturesFromLabels(
 				? service.config.volumes.push('/lib/firmware:/lib/firmware')
 				: null,
 		'io.balena.features.balena-socket': () => {
+			service.config.volumes.push(
+				`${constants.dockerSocket}:${constants.containerDockerSocket}`,
+			);
+
+			// Maintain the /var/run mount for backwards compatibility
 			service.config.volumes.push(
 				`${constants.dockerSocket}:${constants.dockerSocket}`,
 			);
+
 			if (service.config.environment['DOCKER_HOST'] == null) {
 				service.config.environment[
 					'DOCKER_HOST'
-				] = `unix://${constants.dockerSocket}`;
+				] = `unix://${constants.containerDockerSocket}`;
 			}
 			// We keep balena.sock for backwards compatibility
 			if (constants.dockerSocket !== '/var/run/balena.sock') {

src/lib/constants.ts

@@ -11,6 +11,10 @@ const constants = {
 		checkString(process.env.DATABASE_PATH) || '/data/database.sqlite',
 	containerId: checkString(process.env.SUPERVISOR_CONTAINER_ID) || undefined,
 	dockerSocket: process.env.DOCKER_SOCKET || '/var/run/docker.sock',
+
+	// In-container location for docker socket
+	// Mount in /host/run to avoid clashing with systemd
+	containerDockerSocket: '/host/run/balena-engine.sock',
 	supervisorImage:
 		checkString(process.env.SUPERVISOR_IMAGE) || 'resin/rpi-supervisor',
 	ledFile:

test/04-service.spec.ts

@@ -8,6 +8,7 @@ import {
 	ServiceComposeConfig,
 	ServiceConfig,
 } from '../src/compose/types/service';
+import * as constants from '../src/lib/constants';
 
 const configs = {
 	simple: {
@@ -270,6 +271,30 @@ describe('compose/service', () => {
 			]);
 	});
 
+	it('should correctly handle io.balena.features.balena-socket label', async () => {
+		const service = await Service.fromComposeObject(
+			{
+				appId: 123456,
+				serviceId: 123456,
+				serviceName: 'foobar',
+				labels: {
+					'io.balena.features.balena-socket': '1',
+				},
+			},
+			{ appName: 'test' } as any,
+		);
+
+		expect(service.config.volumes).to.include.members([
+			`${constants.dockerSocket}:${constants.dockerSocket}`,
+			`${constants.dockerSocket}:/host/run/balena-engine.sock`,
+			`${constants.dockerSocket}:/var/run/balena.sock`,
+		]);
+
+		expect(service.config.environment['DOCKER_HOST']).to.equal(
+			'unix:///host/run/balena-engine.sock',
+		);
+	});
+
 	describe('Ordered array parameters', () => {
 		it('Should correctly compare ordered array parameters', async () => {
 			const svc1 = await Service.fromComposeObject(