Show better UX when a delta download fails because the image is processing

Change-type: patch
Closes: #679
Signed-off-by: Cameron Diver <cameron@resin.io>

src/compose/images.coffee

@@ -5,7 +5,7 @@ logTypes = require '../lib/log-types'
 constants = require '../lib/constants'
 validation = require '../lib/validation'
 
-{ NotFoundError } = require '../lib/errors'
+{ DeltaStillProcessingError, NotFoundError } = require '../lib/errors'
 
 # image = {
 # 	name: image registry/repo@digest or registry/repo:tag
@@ -78,6 +78,12 @@ module.exports = class Images extends EventEmitter
 				.then =>
 					@logger.logSystemEvent(logTypes.downloadImageSuccess, { image })
 					return true
+				.catch DeltaStillProcessingError, =>
+					# If this is a delta image pull, and the delta still hasn't finished generating,
+					# don't show a failure message, and instead just inform the user that it's remotely
+					# processing
+					@logger.logSystemEvent(logTypes.deltaStillProcessingError)
+					return false
 				.catch (err) =>
 					@logger.logSystemEvent(logTypes.downloadImageError, { image, error: err })
 					return false

src/lib/docker-utils.coffee

@@ -6,7 +6,7 @@ dockerDelta = require 'docker-delta'
 _ = require 'lodash'
 { request, resumable } = require './request'
 { envArrayToObject } = require './conversions'
-{ InvalidNetGatewayError } = require './errors'
+{ DeltaStillProcessingError, InvalidNetGatewayError } = require './errors'
 { checkInt } = require './validation'
 
 applyRsyncDelta = (imgSrc, deltaUrl, applyTimeout, opts, onProgress, log) ->
@@ -104,7 +104,7 @@ module.exports = class DockerUtils extends DockerToolbelt
 				request.getAsync("#{deltaEndpoint}/api/v#{version}/delta?src=#{deltaSource}&dest=#{imgDest}", opts)
 				.spread (res, data) ->
 					if res.statusCode in [ 502, 504 ]
-						throw new Error('Delta server is still processing the delta, will retry')
+						throw new DeltaStillProcessingError()
 					switch version
 						when 2
 							if not (300 <= res.statusCode < 400 and res.headers['location']?)

src/lib/errors.ts

@@ -20,3 +20,5 @@ export function UnitNotLoadedError(err: string[]): boolean {
 }
 
 export class InvalidNetGatewayError extends TypedError { }
+
+export class DeltaStillProcessingError extends TypedError { }

src/lib/log-types.coffee

@@ -57,6 +57,9 @@ module.exports =
 	imageAlreadyDeleted:
 		eventName: 'Image already deleted'
 		humanName: 'Image already deleted'
+	deltaStillProcessingError:
+		eventName: 'Delta still processing remotely.'
+		humanName: 'Delta still processing remotely. Will retry...'
 
 	startService:
 		eventName: 'Service start'