Switch to a new image management system keeping the docker image ID in the database, allowing deltas and proper comparison for images that have a digest.

Signed-off-by: Pablo Carranza Velez <pablo@resin.io>

src/application-manager.coffee

@@ -10,6 +10,7 @@ process.env.DOCKER_HOST ?= "unix://#{constants.dockerSocket}"
 Docker = require './lib/docker-utils'
 updateLock = require './lib/update-lock'
 { checkTruthy, checkInt, checkString } = require './lib/validation'
+{ NotFoundError } = require './lib/errors'
 
 ServiceManager = require './compose/service-manager'
 Service = require './compose/service'
@@ -28,7 +29,7 @@ serviceAction = (action, serviceId, current, target, options) ->
 # TODO: move this to an Image class?
 imageForService = (service) ->
 	return {
-		name: service.image
+		name: service.imageName
 		appId: service.appId
 		serviceId: service.serviceId
 		serviceName: service.serviceName
@@ -186,7 +187,7 @@ module.exports = class ApplicationManager extends EventEmitter
 					@services.kill(step.current)
 					.then =>
 						if step.options?.removeImage
-							@images.remove(imageForService(step.current))
+							@images.removeByDockerId(step.current.image)
 			updateMetadata: (step) =>
 				@services.updateMetadata(step.current, step.target)
 			purge: (step, { force = false } = {}) =>
@@ -238,8 +239,8 @@ module.exports = class ApplicationManager extends EventEmitter
 					@reportCurrentState(update_downloaded: true)
 			removeImage: (step) =>
 				@images.remove(step.image)
-			updateImage: (step) =>
+			saveImage: (step) =>
-				@images.update(step.target)
+				@images.save(step.image)
 			cleanup: (step) =>
 				@images.cleanup()
 			createNetworkOrVolume: (step) =>
@@ -431,6 +432,7 @@ module.exports = class ApplicationManager extends EventEmitter
 				target: targetServicesPerId[serviceId]
 				serviceId
 			})
+
 		return { removePairs, installPairs, updatePairs }
 
 	_compareNetworksOrVolumesForUpdate: (model, { current, target }, appId) ->
@@ -480,19 +482,6 @@ module.exports = class ApplicationManager extends EventEmitter
 	compareVolumesForUpdate: ({ current, target }, appId) =>
 		@_compareNetworksOrVolumesForUpdate(@volumes, { current, target }, appId)
 
-	# TODO: should we consider the case where several services use the same image?
-	# In such case we should do more complex matching to allow several image objects
-	# with the same name but different metadata. For now this shouldn't be necessary
-	# because the Resin model requires a different imageId and name for each service.
-	compareImagesForMetadataUpdate: (availableImages, targetServices) ->
-		pairs = []
-		targetImages = _.map(targetServices, imageForService)
-		for target in targetImages
-			imageWithSameContent = _.find(availableImages, (img) => @images.isSameImage(img, target))
-			if imageWithSameContent? and !_.find(availableImages, (img) -> _.isEqual(_.omit(img, 'id'), target))
-				pairs.push({ current: imageWithSameContent, target, serviceId: target.serviceId })
-		return pairs
-
 	# Checks if a service is using a network or volume that is about to be updated
 	_hasCurrentNetworksOrVolumes: (service, networkPairs, volumePairs) ->
 		if !service?
@@ -537,7 +526,7 @@ module.exports = class ApplicationManager extends EventEmitter
 		if target.dependsOn?
 			for dependency in target.dependsOn
 				dependencyService = _.find(targetApp.services, (s) -> s.serviceName == dependency)
-				if !_.find(availableImages, (image) => @images.isSameImage(image, { name: dependencyService.image }))?
+				if !_.find(availableImages, (image) => @images.isSameImage(image, { name: dependencyService.imageName }))?
 					return false
 		return true
 
@@ -619,7 +608,7 @@ module.exports = class ApplicationManager extends EventEmitter
 			# There is already a step in progress for this service, so we wait
 			return null
 
-		needsDownload = !_.some(availableImages, (image) => @images.isSameImage(image, { name: target.image }))
+		needsDownload = !_.some(availableImages, (image) => @images.isSameImage(image, { name: target.imageName }))
 		dependenciesMetForStart = =>
 			@_dependenciesMetForServiceStart(target, networkPairs, volumePairs, installPairs.concat(updatePairs), stepsInProgress)
 		dependenciesMetForKill = =>
@@ -656,7 +645,6 @@ module.exports = class ApplicationManager extends EventEmitter
 		networkPairs = @compareNetworksForUpdate({ current: currentApp.networks, target: targetApp.networks }, appId)
 		volumePairs = @compareVolumesForUpdate({ current: currentApp.volumes, target: targetApp.volumes }, appId)
 		{ removePairs, installPairs, updatePairs } = @compareServicesForUpdate(currentApp.services, targetApp.services)
-		imagePairs = @compareImagesForMetadataUpdate(availableImages, targetApp.services)
 		steps = []
 		# All removePairs get a 'kill' action
 		for pair in removePairs
@@ -676,8 +664,6 @@ module.exports = class ApplicationManager extends EventEmitter
 		for pair in volumePairs
 			pairSteps = @_nextStepsForVolume(pair, currentApp, removePairs.concat(updatePairs))
 			steps = steps.concat(pairSteps)
-		for pair in imagePairs
-			steps.push(_.assign({ action: 'updateImage' }, pair))
 		return steps
 
 	normaliseAppForDB: (app) =>
@@ -705,13 +691,16 @@ module.exports = class ApplicationManager extends EventEmitter
 
 	createTargetService: (service, opts) ->
 		@images.inspectByName(service.image)
-		.catchReturn(undefined)
+		.catchReturn(NotFoundError, undefined)
 		.then (imageInfo) ->
 			serviceOpts = {
 				serviceName: service.serviceName
 				imageInfo
 			}
 			_.assign(serviceOpts, opts)
+			service.imageName = service.image
+			if imageInfo?.Id?
+				service.image = imageInfo.Id
 			return new Service(service, serviceOpts)
 
 	normaliseAndExtendAppFromDB: (app) =>
@@ -803,30 +792,40 @@ module.exports = class ApplicationManager extends EventEmitter
 				return availableImage.name
 		return 'resin/scratch'
 
-	# return images that:
+	# returns:
+	# imagesToRemove: images that
 	# - are not used in the current state, and
 	# - are not going to be used in the target state, and
 	# - are not needed for delta source / pull caching or would be used for a service with delete-then-download as strategy
-	_unnecessaryImages: (current, target, available) =>
+	# imagesToSave: images that
+	# - are locally available (i.e. an image with the same digest exists)
+	# - are not saved to the DB with all their metadata (serviceId, serviceName, etc)
+	_compareImages: (current, target, available) =>
 
-		allImagesForApp = (app) -> _.map(app.services, imageForService)
+		allImagesForTargetApp = (app) -> _.map(app.services, imageForService)
-
+		allImagesForCurrentApp = (app) ->
-		currentImages = _.flatten(_.map(current.local.apps, allImagesForApp))
+			_.map app.services, (service) ->
-		targetImages = _.flatten(_.map(target.local.apps, allImagesForApp))
+				_.omit(_.find(available, (image) -> image.dockerImageId == service.image), [ 'dockerImageId', 'id' ])
-		availableAndUnused = _.filter available, (image) =>
+		availableWithoutIds = _.map(available, (image) -> _.omit(image, [ 'dockerImageId', 'id' ]))
-			!_.some currentImages.concat(targetImages), (imageInUse) => @images.isSameImage(image, imageInUse)
+		currentImages = _.flatten(_.map(current.local.apps, allImagesForCurrentApp))
+		targetImages = _.flatten(_.map(target.local.apps, allImagesForTargetApp))
+		availableAndUnused = _.filter availableWithoutIds, (image) ->
+			!_.some currentImages.concat(targetImages), (imageInUse) -> _.isEqual(image, imageInUse)
 		imagesToDownload = _.filter targetImages, (targetImage) =>
 			!_.some available, (availableImage) => @images.isSameImage(availableImage, targetImage)
+		# Images that are available but we don't have them in the DB with the exact metadata:
+		imagesToSave = _.filter targetImages, (targetImage) =>
+			_.some(available, (availableImage) => @images.isSameImage(availableImage, targetImage)) and
+				!_.find(availableWithoutIds, (img) -> _.isEqual(img, targetImage))?
 
 		deltaSources = _.map imagesToDownload, (image) =>
 			return @bestDeltaSource(image, available)
-
 		proxyvisorImages = @proxyvisor.imagesInUse(current, target)
-
+		imagesToRemove = _.filter availableAndUnused, (image) =>
-		return _.filter availableAndUnused, (image) =>
 			notUsedForDelta = !_.some deltaSources, (deltaSource) -> deltaSource == image.name
 			notUsedByProxyvisor = !_.some proxyvisorImages, (proxyvisorImage) => @images.isSameImage(image, { name: proxyvisorImage })
 			return notUsedForDelta and notUsedByProxyvisor
+		return { imagesToSave, imagesToRemove }
 
 	_inferNextSteps: (cleanupNeeded, availableImages, supervisorNetworkReady, current, target, stepsInProgress) =>
 		Promise.try =>
@@ -839,7 +838,10 @@ module.exports = class ApplicationManager extends EventEmitter
 				if !_.some(stepsInProgress, (step) -> step.action == 'fetch')
 					if cleanupNeeded
 						nextSteps.push({ action: 'cleanup' })
-					imagesToRemove = @_unnecessaryImages(current, target, availableImages)
+					{ imagesToRemove, imagesToSave } = @_compareImages(current, target, availableImages)
+					for image in imagesToSave
+						nextSteps.push({ action: 'saveImage', image })
+					if _.isEmpty(imagesToSave)
 						for image in imagesToRemove
 							nextSteps.push({ action: 'removeImage', image })
 				# If we have to remove any images, we do that before anything else

src/compose/images.coffee

@@ -8,13 +8,14 @@ validation = require '../lib/validation'
 { NotFoundError } = require '../lib/errors'
 
 # image = {
-# 	name: image registry/repo:tag
+# 	name: image registry/repo@digest or registry/repo:tag
 # 	appId
 # 	serviceId
 # 	serviceName
 # 	imageId (from resin API)
 # 	releaseId
 # 	dependent
+# 	dockerImageId
 # 	status Downloading, Downloaded, Deleting
 # 	downloadProgress
 # }
@@ -45,15 +46,25 @@ module.exports = class Images extends EventEmitter
 			@markAsSupervised(image)
 			.then =>
 				@inspectByName(imageName)
+				.tap (img) =>
+					@db.models('image').update({ dockerImageId: img.Id }).where(image)
 			.catch =>
 				@reportChange(image.imageId, _.merge(_.clone(image), { status: 'Downloading', downloadProgress: 0 }))
 				Promise.try =>
 					if validation.checkTruthy(opts.delta)
 						@logger.logSystemEvent(logTypes.downloadImageDelta, { image })
+						Promise.try =>
+							if opts.deltaSource
+								@inspectByName(opts.deltaSource)
+								.then (srcImage) ->
+									opts.deltaSourceId = srcImage.Id
+						.then =>
 							@docker.rsyncImageWithProgress(imageName, opts, onProgress)
 					else
 						@logger.logSystemEvent(logTypes.downloadImage, { image })
 						@docker.fetchImageWithProgress(imageName, opts, onProgress)
+				.then (id) =>
+					@db.models('image').update({ dockerImageId: id }).where(image)
 				.then =>
 					@logger.logSystemEvent(logTypes.downloadImageSuccess, { image })
 					@inspectByName(imageName)
@@ -68,7 +79,8 @@ module.exports = class Images extends EventEmitter
 		image.serviceName ?= null
 		image.imageId ?= null
 		image.releaseId ?= null
-		image.dependent ?= false
+		image.dependent ?= 0
+		image.dockerImageId ?= null
 		return _.omit(image, 'id')
 
 	markAsSupervised: (image) =>
@@ -79,39 +91,64 @@ module.exports = class Images extends EventEmitter
 		image = @format(image)
 		@db.models('image').update(image).where(name: image.name)
 
-	_removeImageIfNotNeeded: (image) =>
+	save: (image) =>
 		@inspectByName(image.name)
 		.then (img) =>
-			@db.models('image').where(name: image.name).select()
+			image = _.clone(image)
-			.then (imagesFromDB) =>
+			image.dockerImageId = img.Id
-				if imagesFromDB.length == 1 and _.isEqual(@format(imagesFromDB[0]), @format(image))
+			@markAsSupervised(image)
-					@docker.getImage(image.name).remove(force: true)
-		.return(true)
-		.catchReturn(NotFoundError, false)
 
-	remove: (image) =>
+	_removeImageIfNotNeeded: (image) =>
+		# We first fetch the image from the DB to ensure it exists,
+		# and get the dockerImageId and any other missing field
+		@db.models('image').select().where(image)
+		.then (images) =>
+			if images.length == 0
+				return false
+			img = images[0]
+			Promise.try =>
+				if !img.dockerImageId?
+					# Legacy image from before we started using dockerImageId, so we try to remove it by name
+					@docker.getImage(img.name).remove(force: true)
+					.return(true)
+				else
+					@db.models('image').where(dockerImageId: img.dockerImageId).select()
+					.then (imagesFromDB) =>
+						if imagesFromDB.length == 1 and _.isEqual(@format(imagesFromDB[0]), @format(img))
 							@reportChange(image.imageId, _.merge(_.clone(image), { status: 'Deleting' }))
 							@logger.logSystemEvent(logTypes.deleteImage, { image })
-		@_removeImageIfNotNeeded(image)
+							@docker.getImage(img.dockerImageId).remove(force: true)
+							.return(true)
+						else
+							return false
+			.catchReturn(NotFoundError, false)
 			.tap =>
-			@db.models('image').del().where(image)
+				@db.models('image').del().where(id: img.id)
 		.then (removed) =>
 			if removed
 				@logger.logSystemEvent(logTypes.deleteImageSuccess, { image })
-			else
+		.finally =>
-				@logger.logSystemEvent(logTypes.imageAlreadyDeleted, { image })
+			@reportChange(image.imageId)
+
+	remove: (image) =>
+		@_removeImageIfNotNeeded(image)
 		.catch (err) =>
 			@logger.logSystemEvent(logTypes.deleteImageError, { image, error: err })
 			throw err
-		.finally =>
+
-			@reportChange(image.imageId)
+	getByDockerId: (id) =>
+		@db.models('image').where(dockerImageId: id).first()
+
+	removeByDockerId: (id) =>
+		@getByDockerId(id)
+		.then(@remove)
 
 	getNormalisedTags: (image) ->
 		Promise.map(image.RepoTags ? [], (tag) => @normalise(tag))
 
 	_withImagesFromDockerAndDB: (callback) =>
 		Promise.join(
-			@docker.listImages()
+			@docker.listImages(digests: true)
 			.map (image) =>
 				image.NormalisedRepoTags = @getNormalisedTags(image)
 				Promise.props(image)
@@ -119,9 +156,13 @@ module.exports = class Images extends EventEmitter
 			callback
 		)
 
-	_isAvailableInDocker: (image, dockerImages) ->
+	_matchesTagOrDigest: (image, dockerImage) ->
-		_.some dockerImages, (dockerImage) ->
+		return _.includes(dockerImage.NormalisedRepoTags, image.name) or
-			_.includes(dockerImage.NormalisedRepoTags, image.name) or _.includes(dockerImage.RepoDigests, image.name)
+			_.some(dockerImage.RepoDigests, (digest) -> Images.hasSameDigest(image.name, digest))
+
+	_isAvailableInDocker: (image, dockerImages) =>
+		_.some dockerImages, (dockerImage) =>
+			@_matchesTagOrDigest(image, dockerImage) or image.dockerImageId == dockerImage.Id
 
 	# Gets all images that are supervised, in an object containing name, appId, serviceId, serviceName, imageId, dependent.
 	getAvailable: =>
@@ -130,7 +171,17 @@ module.exports = class Images extends EventEmitter
 
 	cleanupDatabase: =>
 		@_withImagesFromDockerAndDB (dockerImages, supervisedImages) =>
-			return _.filter(supervisedImages, (image) => !@_isAvailableInDocker(image, dockerImages))
+			Promise.map supervisedImages, (image) =>
+				# If the supervisor was interrupted between fetching an image and storing its id,
+				# some entries in the db might need to have the dockerImageId populated
+				if !image.dockerImageId?
+					id = _.find(dockerImages, (dockerImage) => @_matchesTagOrDigest(image, dockerImage))?.Id
+					if id?
+						@db.models('image').update(dockerImageId: id).where(image)
+						.then ->
+							image.dockerImageId = id
+			.then =>
+				_.filter(supervisedImages, (image) => !@_isAvailableInDocker(image, dockerImages))
 		.then (imagesToRemove) =>
 			ids = _.map(imagesToRemove, 'id')
 			@db.models('image').del().whereIn('id', ids)
@@ -147,35 +198,56 @@ module.exports = class Images extends EventEmitter
 				status[image.imageId] ?= image
 			return _.values(status)
 
-	_getOldSupervisorsForCleanup: =>
+	_getImagesForCleanup: =>
 		images = []
+		Promise.join(
 			@docker.getRegistryAndName(constants.supervisorImage)
-		.then (supervisorImageInfo) =>
+			@db.models('image').select('dockerImageId')
-			@docker.listImages()
+			.map((image) -> image.dockerImageId)
+			(supervisorImageInfo, usedImageIds) =>
+				@docker.listImages(digests: true)
 				.map (image) =>
-				Promise.map image.RepoTags ? [], (repoTag) =>
+					# Cleanup should remove truly dangling images (i.e. dangling and with no digests)
+					if _.isEmpty(image.RepoTags) and _.isEmpty(image.RepoDigests) and not image.Id in usedImageIds
+						images.push(image.Id)
+					else if !_.isEmpty(image.RepoTags)
+						# We also remove images from the supervisor repository with a different tag
+						Promise.map image.RepoTags, (repoTag) =>
 							@docker.getRegistryAndName(repoTag)
 							.then ({ imageName, tagName }) ->
 								if imageName == supervisorImageInfo.imageName and tagName != supervisorImageInfo.tagName
-							images.push(repoTag)
+									images.push(image.Id)
+		)
+		.then(_.uniq)
 		.then =>
 			return _.filter images, (image) =>
 				!@imageCleanupFailures[image]? or Date.now() - @imageCleanupFailures[image] > constants.imageCleanupErrorIgnoreTimeout
 
 	inspectByName: (imageName) =>
 		@docker.getImage(imageName).inspect()
+		.catch NotFoundError, (err) =>
+			digest = imageName.split('@')[1]
+			if !digest?
+				throw err
+			@db.models('image').where('name', 'like', "%@#{digest}").select()
+			.then (imagesFromDB) =>
+				for image in imagesFromDB
+					if image.dockerImageId?
+						return @docker.getImage(image.dockerImageId).inspect()
+				throw err
+
 
 	normalise: (imageName) =>
 		@docker.normaliseImageName(imageName)
 
 	isCleanupNeeded: =>
-		@_getOldSupervisorsForCleanup()
+		@_getImagesForCleanup()
 		.then (imagesForCleanup) ->
 			return !_.isEmpty(imagesForCleanup)
 
-	# Delete old supervisor images
+	# Delete dangling images and old supervisor images
 	cleanup: =>
-		@_getOldSupervisorsForCleanup()
+		@_getImagesForCleanup()
 		.map (image) =>
 			console.log("Cleaning up #{image}")
 			@docker.getImage(image).remove(force: true)
@@ -185,9 +257,12 @@ module.exports = class Images extends EventEmitter
 				@logger.logSystemMessage("Error cleaning up #{image}: #{err.message} - will ignore for 1 hour", { error: err }, 'Image cleanup error')
 				@imageCleanupFailures[image] = Date.now()
 
+	@hasSameDigest: (name1, name2) ->
+		hash1 = name1.split('@')[1]
+		hash2 = name2.split('@')[1]
+		return hash1? and hash1 == hash2
+
 	@isSameImage: (image1, image2) ->
-		hash1 = image1.name.split('@')[1]
+		return image1.name == image2.name or Images.hasSameDigest(image1.name, image2.name)
-		hash2 = image2.name.split('@')[1]
-		return image1.name == image2.name or (hash1? and hash1 == hash2)
 
 	isSameImage: @isSameImage

src/compose/networks.coffee

@@ -10,9 +10,11 @@ module.exports = class Networks
 
 	# TODO: parse supported config fields
 	format: (network) ->
-		[ appId, name ] = network.Name.split('_')
+		m = /^([0-9]+)_(.+)$/.match(network.Name)
+		appId = checkInt(m[1])
+		name = m[2]
 		return {
-			appId: checkInt(appId)
+			appId: appId
 			name: name
 			config: {}
 		}

src/compose/service.coffee

@@ -6,7 +6,6 @@ constants = require '../lib/constants'
 conversions =  require '../lib/conversions'
 
 Duration = require 'duration-js'
-Images = require './images'
 
 validRestartPolicies = [ 'no', 'always', 'on-failure', 'unless-stopped' ]
 
@@ -112,6 +111,7 @@ module.exports = class Service
 	constructor: (serviceProperties, opts = {}) ->
 		{
 			@image
+			@imageName
 			@expose
 			@ports
 			@networkMode
@@ -553,6 +553,7 @@ module.exports = class Service
 
 	isSameContainer: (otherService) =>
 		propertiesToCompare = [
+			'image'
 			'command'
 			'entrypoint'
 			'networkMode'
@@ -590,8 +591,7 @@ module.exports = class Service
 			'extraHosts'
 			'ulimitsArray'
 		]
-		isEq = Images.isSameImage({ name: @image }, { name: otherService.image }) and
+		isEq = _.isEqual(_.pick(this, propertiesToCompare), _.pick(otherService, propertiesToCompare)) and
-			_.isEqual(_.pick(this, propertiesToCompare), _.pick(otherService, propertiesToCompare)) and
 			@hasSameNetworks(otherService) and
 			_.every arraysToCompare, (property) =>
 				_.isEmpty(_.xorWith(this[property], otherService[property], _.isEqual))

src/compose/volumes.coffee

@@ -12,10 +12,12 @@ module.exports = class Volumes
 	constructor: ({ @docker, @logger }) ->
 
 	format: (volume) =>
-		[ appId, name ] = volume.Name.split('_')
+		m = /^([0-9]+)_(.+)$/.match(volume.Name)
+		appId = checkInt(m[1])
+		name = m[2]
 		return {
 			name: name
-			appId: checkInt(appId)
+			appId: appId
 			config: {
 				labels: _.omit(volume.Labels, _.keys(@defaultLabels(appId)))
 				driverOpts: volume.Options

src/lib/docker-utils.coffee

@@ -49,13 +49,14 @@ module.exports = class DockerUtils extends DockerToolbelt
 		{
 			deltaRequestTimeout, deltaApplyTimeout, deltaRetryCount, deltaRetryInterval,
 			uuid, currentApiKey, deltaEndpoint, resinApiEndpoint,
-			deltaSource, startFromEmpty = false
+			deltaSource, deltaSourceId, startFromEmpty = false
 		} = fullDeltaOpts
 		retryCount = checkInt(deltaRetryCount)
 		retryInterval = checkInt(deltaRetryInterval)
 		requestTimeout = checkInt(deltaRequestTimeout)
 		applyTimeout = checkInt(deltaApplyTimeout)
 		deltaSource = 'resin/scratch' if startFromEmpty or !deltaSource?
+		deltaSourceId ?= deltaSource
 		# I'll leave this debug log here in case we ever wonder what delta source a device is using in production
 		console.log("Using delta source #{deltaSource}")
 		Promise.join @getRegistryAndName(imgDest), @getRegistryAndName(deltaSource), (dstInfo, srcInfo) ->
@@ -92,14 +93,10 @@ module.exports = class DockerUtils extends DockerToolbelt
 							if deltaSource is 'resin/scratch'
 								deltaSrc = null
 							else
-								deltaSrc = deltaSource
+								deltaSrc = deltaSourceId
 							resumeOpts = { maxRetries: retryCount, retryInterval }
 							resolve(applyDelta(deltaSrc, deltaUrl, { requestTimeout, applyTimeout, resumeOpts }, onProgress))
 					.on 'error', reject
-		.then (id) =>
-			@getRepoAndTag(imgDest)
-			.then ({ repo, tag }) =>
-				@getImage(id).tag({ repo, tag, force: true })
 		.catch dockerDelta.OutOfSyncError, (err) =>
 			throw err if startFromEmpty
 			console.log('Falling back to delta-from-empty')
@@ -109,13 +106,15 @@ module.exports = class DockerUtils extends DockerToolbelt
 
 	fetchImageWithProgress: (image, { uuid, currentApiKey }, onProgress) =>
 		@getRegistryAndName(image)
-		.then ({ registry, imageName, tagName }) =>
+		.then ({ registry }) =>
 			dockerOptions =
 				authconfig:
 					username: 'd_' + uuid,
 					password: currentApiKey,
 					serveraddress: registry
 			@dockerProgress.pull(image, onProgress, dockerOptions)
+			.then =>
+				@getImage(image).inspect().get('Id')
 
 	getImageEnv: (id) ->
 		@getImage(id).inspect()

src/migrations/20171214172530_image_docker_id.js

@@ -0,0 +1,10 @@
+// Adds a dockerImageId column to the image table to identify images downloaded with deltas
+exports.up = function (knex, Promise) {
+	return knex.schema.table('image', (t) => {
+			t.string('dockerImageId')
+		})
+}
+
+exports.down = function(knex, Promise) {
+	return Promise.try(() => { throw new Error('Not implemented') })
+}