Initial version of self-updates, adds an "/v1/update-supervisor" endpoint that can be posted to in order to trigger a supervisor update, which it then fetches as the resin/rpi-supervisor repo of the registry endpoint.

package.json

@@ -12,7 +12,7 @@
     "express": "~3.2.6",
     "lodash": "~2.4.1",
     "csr-gen": "~0.2.1",
-    "dockerode": "~0.2.5",
+    "dockerode": "~2.0.0",
     "knex": "~0.5.1",
     "bluebird": "~1.1.1",
     "JSONStream": "~0.7.1",

src/api.coffee

@@ -3,6 +3,7 @@ fs = Promise.promisifyAll require 'fs'
 utils = require './utils'
 express = require 'express'
 application = require './application'
+supervisor = require './supervisor-update'
 
 api = express()
 
@@ -25,4 +26,9 @@ api.post '/v1/update', (req, res) ->
 	application.update()
 	res.send(204)
 
+api.post '/v1/update-supervisor', (req, res) ->
+	console.log('Got supervisor update')
+	supervisor.update()
+	res.send(204)
+
 module.exports = api

src/supervisor-update.coffee

@@ -0,0 +1,71 @@
+es = require 'event-stream'
+Docker = require 'dockerode'
+Promise = require 'bluebird'
+JSONStream = require 'JSONStream'
+config = require './config'
+
+DOCKER_SOCKET = '/run/docker.sock'
+
+docker = Promise.promisifyAll(new Docker(socketPath: DOCKER_SOCKET))
+# Hack dockerode to promisify internal classes' prototypes
+Promise.promisifyAll(docker.getImage().__proto__)
+Promise.promisifyAll(docker.getContainer().__proto__)
+
+supervisorTag = 'resin/rpi-supervisor'
+updateImage = config.REGISTRY_ENDPOINT + '/' + supervisorTag
+
+supervisorUpdating = Promise.resolve()
+exports.update = ->
+	# Make sure only one attempt to update the full supervisor is running at a time, ignoring any errors from previous update attempts
+	supervisorUpdating = supervisorUpdating.catch(->).then -> 
+		console.log('Fetching updated supervisor:', updateImage)
+		docker.createImageAsync(fromImage: updateImage)
+	.then (stream) ->
+		deferred = Promise.defer()
+
+		if stream.headers['content-type'] is 'application/json'
+			stream.pipe(JSONStream.parse('error'))
+			.pipe es.mapSync (error) ->
+				deferred.reject(error)
+		else
+			stream.pipe es.wait (error, text) -> deferred.reject(text)
+
+		stream.on 'end', -> deferred.resolve()
+
+		return deferred.promise
+	.then ->
+		console.log('Tagging updated supervisor:', updateImage)
+		docker.getImage(updateImage).tagAsync(
+			repo: supervisorTag
+			force: true
+		)
+	.then ->
+		console.log('Creating updated supervisor container:', supervisorTag)
+		docker.createContainerAsync(
+			Image: supervisorTag
+			Cmd: ['/start']
+			Volumes:
+				'/boot/config.json': '/mnt/mmcblk0p1/config.json',
+				'/data': '/var/lib/docker/data',
+				'/run/docker.sock': '/var/run/docker.sock'
+			Env: [
+				'API_ENDPOINT=' + config.API_ENDPOINT
+				'REGISTRY_ENDPOINT=' + config.REGISTRY_ENDPOINT
+			]
+		)
+	.then (container) ->
+		console.log('Starting updated supervisor container:', supervisorTag)
+		container.startAsync(
+			Privileged: true
+			Binds: [
+				'/mnt/mmcblk0p1/config.json:/boot/config.json'
+				'/var/run/docker.sock:/run/docker.sock'
+				'/var/lib/docker/data:/data'
+			]
+		)
+	.then ->
+		# We've started the new container, so we're done here! #pray
+		process.exit()
+	.catch (err) ->
+		console.error('Error updating supervisor:', err)
+		throw err