added redis write check to healthcheck

services/track-changes/app.coffee

@@ -47,6 +47,8 @@ app.post "/pack", (req, res, next) ->
 app.get "/status", (req, res, next) ->
 	res.send "track-changes is alive"
 
+app.get "/check_lock", HttpController.checkLock
+
 app.get "/health_check",  HttpController.healthCheck
 
 app.use (error, req, res, next) ->

services/track-changes/app/coffee/HealthChecker.coffee

@@ -11,6 +11,14 @@ module.exports =
 		url = "http://localhost:#{port}/project/#{project_id}"
 		logger.log project_id:project_id, "running health check"
 		jobs = [
+			(cb)->
+				request.get {url:"http://localhost:#{port}/check_lock", timeout:3000}, (err, res, body) ->
+					if err?
+						cb(err)
+					else if res?.statusCode != 200
+						cb("status code not 200, it's #{res.statusCode}")
+					else
+						cb()
 			(cb)->
 				request.post {url:"#{url}/flush", timeout:3000}, (err, res, body) ->
 					if err?

services/track-changes/app/coffee/HttpController.coffee

@@ -5,6 +5,7 @@ RestoreManager = require "./RestoreManager"
 logger = require "logger-sharelatex"
 DocArchiveManager = require "./DocArchiveManager"
 HealthChecker = require "./HealthChecker"
+LockManager = require "./LockManager"
 
 module.exports = HttpController =
 	flushDoc: (req, res, next = (error) ->) ->
@@ -90,3 +91,11 @@ module.exports = HttpController =
 				res.send 500
 			else
 				res.send 200
+
+	checkLock: (req, res)->
+		LockManager.healthCheck (err) ->
+			if err?
+				logger.err err:err, "error performing lock check"
+				res.send 500
+			else
+				res.send 200

services/track-changes/app/coffee/LockManager.coffee

@@ -66,4 +66,7 @@ module.exports = LockManager =
 					return callback(error) if error?
 					callback()
 
-	
+	healthCheck: (callback) ->
+		action = (releaseLock) ->
+			releaseLock()
+		LockManager.runWithLock	"HistoryLock:HealthCheck:host=#{HOST}:pid=#{PID}:random=#{RND}", action, callback