device-api: Add container id endpoint

Change-type: minor
Signed-off-by: Cameron Diver <cameron@balena.io>

docs/API.md

@@ -793,6 +793,41 @@ Response:
 }
 ```
 
+### Container ID (GET /v2/containerId)
+
+Added in supervisor v8.6.0
+
+Use this endpoint to match a service name to a container ID.
+
+From the user container:
+```
+$ curl "$BALENA_SUPERVISOR_ADDRESS/v2/containerId?apikey=$BALENA_SUPERVISOR_API_KEY"
+```
+
+Response:
+```json
+{
+	"status": "success",
+	"services": {
+		"service-one": "ad6d5d32576ad3cb1fcaa59b564b8f6f22b079631080ab1a3bbac9199953eb7d",
+		"service-two": "756535dc6e9ab9b560f84c85063f55952273a23192641fc2756aa9721d9d1000"
+	}
+}
+```
+
+You can also specify a service, to return only that container id:
+```
+$ curl "$BALENA_SUPERVISOR_ADDRESS/v2/containerId?apikey=$BALENA_SUPERVISOR_API_KEY&service=service-one"
+```
+
+Response:
+```json
+{
+	"status": "sucess",
+	"containerId": "ad6d5d32576ad3cb1fcaa59b564b8f6f22b079631080ab1a3bbac9199953eb7d"
+}
+```
+
 ### Local mode endpoints
 
 These endpoints are mainly for use by the CLI, for working with a local mode device.

src/compose/service-manager.d.ts

@@ -1,3 +1,4 @@
+import * as Bluebird from 'bluebird';
 import { EventEmitter } from 'events';
 
 import { Service } from '../compose/service';
@@ -5,6 +6,7 @@ import { Service } from '../compose/service';
 // FIXME: Unfinished definition for this class...
 declare class ServiceManager extends EventEmitter {
 	public getStatus(): Service[];
+	public getAll(): Bluebird<Service[]>;
 }
 
 export = ServiceManager;

src/device-api/v2.ts

@@ -337,4 +337,42 @@ export function createV2Api(router: Router, applications: ApplicationManager) {
 			version: supervisorVersion,
 		});
 	});
+
+	router.get('/v2/containerId', async (req, res) => {
+		try {
+			const services = await applications.services.getAll();
+
+			if (req.query.serviceName != null || req.query.service != null) {
+				const serviceName = req.query.serviceName || req.query.service;
+				const service = _.find(
+					services,
+					svc => svc.serviceName === serviceName,
+				);
+				if (service != null) {
+					res.status(200).json({
+						status: 'success',
+						containerId: service.containerId,
+					});
+				} else {
+					res.status(503).json({
+						status: 'failed',
+						message: 'Could not find service with that name',
+					});
+				}
+			} else {
+				res.status(200).json({
+					status: 'success',
+					services: _(services)
+						.keyBy('serviceName')
+						.mapValues('containerId')
+						.value(),
+				});
+			}
+		} catch (e) {
+			res.status(503).json({
+				status: 'failed',
+				message: messageFromError(e),
+			});
+		}
+	});
 }