Add listener for container events and reattach on restart

CHANGELOG.md

@@ -1,3 +1,4 @@
+* Add listener for container events and reattach on restart [Pablo]
 * fix deltas by not using the supervisor as source [Pablo]
 
 # v1.11.2

package.json

@@ -6,6 +6,7 @@
     "start": "./entry.sh"
   },
   "dependencies": {
+    "JSONStream": "^1.1.2",
     "blinking": "~0.0.2",
     "bluebird": "^2.9.24",
     "body-parser": "^1.12.0",

src/application.coffee

@@ -14,6 +14,7 @@ lockFile = Promise.promisifyAll(require('lockfile'))
 bootstrap = require './bootstrap'
 TypedError = require 'typed-error'
 fs = Promise.promisifyAll(require('fs'))
+JSONStream = require 'JSONStream'
 
 class UpdatesLockedError extends TypedError
 
@@ -67,6 +68,14 @@ logTypes =
 		eventName: 'Application update error'
 		humanName: 'Failed to update application'
 
+	appExit:
+		eventName: 'Application exit'
+		humanName: 'Application exited'
+
+	appRestart:
+		eventName: 'Application restart'
+		humanName: 'Restarting application'
+
 logSystemMessage = (message, obj, eventName) ->
 	logger.log({ message, isSystem: true })
 	utils.mixpanelTrack(eventName ? message, obj)
@@ -644,7 +653,38 @@ application.update = update = (force) ->
 			# Set the updating as finished in its own block, so it never has to worry about other code stopping this.
 			updateStatus.state = UPDATE_IDLE
 
+listenToEvents = do ->
+	appHasDied = {}
+	return ->
+		docker.getEventsAsync()
+		.then (stream) ->
+			stream.on 'error', (err) ->
+				console.error('Error on docker events stream:', err, err.stack)
+			parser = JSONStream.parse()
+			parser.on 'error', (err) ->
+				console.error('Error on docker events JSON stream:', err, err.stack)
+			parser.on 'data', (data) ->
+				if data?.Type? && data.Type == 'container' && data.status in ['die', 'start']
+					knex('app').select().where({ containerId: data.id })
+					.then ([ app ]) ->
+						if app?
+							if data.status == 'die'
+								logSystemEvent(logTypes.appExit, app)
+								appHasDied[app.containerId] = true
+							else if data.status == 'start' and appHasDied[app.containerId]
+								logSystemEvent(logTypes.appRestart, app)
+								logger.attach(app)
+					.catch (err) ->
+						console.error('Error on docker event:', err, err.stack)
+			parser.on 'end', ->
+				console.error('Docker events stream ended, this should never happen')
+				listenToEvents()
+			stream.pipe(parser)
+		.catch (err) ->
+			console.error('Error listening to events:', err, err.stack)
+
 application.initialize = ->
+	listenToEvents()
 	knex('app').select()
 	.then (apps) ->
 		Promise.map apps, (app) ->

src/lib/logger.coffee

@@ -51,9 +51,18 @@ exports.disableLogPublishing = (disable) ->
 exports.log = ->
 	publish(arguments...)
 
-exports.attach = (app) ->
-	dockerPromise.then (docker) ->
-		docker.getContainer(app.containerId)
-		.attachAsync({ stream: true, stdout: true, stderr: true, tty: true })
-		.then (stream) ->
-			stream.pipe(es.split()).on('data', publish)
+do ->
+	attached = {}
+	exports.attach = (app) ->
+		if !attached[app.containerId]
+			dockerPromise.then (docker) ->
+				docker.getContainer(app.containerId)
+				.attachAsync({ stream: true, stdout: true, stderr: true, tty: true })
+				.then (stream) ->
+					attached[app.containerId] = true
+					stream.pipe(es.split())
+					.on('data', publish)
+					.on 'error', ->
+						attached[app.containerId] = false
+					.on 'end', ->
+						attached[app.containerId] = false