add db queue file for global db query queues

services/clsi/app/coffee/DbQueue.coffee

@@ -0,0 +1,13 @@
+async = require "async"
+
+queue = async.queue((task, cb)->
+		console.log("running task")
+		task(cb)
+	, 1)
+
+queue.drain = ()->
+    console.log('HI all items have been processed')
+    
+module.exports = 
+	queue: queue
+

services/clsi/app/coffee/ProjectPersistenceManager.coffee

@@ -1,6 +1,7 @@
 UrlCache = require "./UrlCache"
 CompileManager = require "./CompileManager"
 db = require "./db"
+dbQueue = require "./DbQueue"
 async = require "async"
 logger = require "logger-sharelatex"
 oneDay = 24 * 60 * 60 * 1000
@@ -11,15 +12,18 @@ module.exports = ProjectPersistenceManager =
 	EXPIRY_TIMEOUT: Settings.project_cache_length_ms || oneDay * 2.5
 
 	markProjectAsJustAccessed: (project_id, callback = (error) ->) ->
+		job = (cb)->
 			console.log("markProjectAsJustAccessed")
 			db.Project.findOrCreate(where: {project_id: project_id})
 				.spread(
 					(project, created) ->
 						project.updateAttributes(lastAccessed: new Date())
-						.then(() -> callback())
+							.then(() -> cb())
-						.error callback
+							.error cb
 				)
-			.error callback
+				.error cb
+		dbQueue.queue.push(job, callback)
+
 
 	clearExpiredProjects: (callback = (error) ->) ->
 		ProjectPersistenceManager._findExpiredProjectIds (error, project_ids) ->
@@ -54,16 +58,22 @@ module.exports = ProjectPersistenceManager =
 				callback()
 
 	_clearProjectFromDatabase: (project_id, callback = (error) ->) ->
+		job = (cb)->
 			console.log("_clearProjectFromDatabase")
 			db.Project.destroy(where: {project_id: project_id})
 				.then(() -> callback())
 				.error callback
+		dbQueue.queue.push(job, callback)
+
 
 	_findExpiredProjectIds: (callback = (error, project_ids) ->) ->
+		job = (cb)->
 			console.log("_findExpiredProjectIds")
 			db.Project.findAll(where: ["lastAccessed < ?", new Date(Date.now() - ProjectPersistenceManager.EXPIRY_TIMEOUT)])
 				.then((projects) ->
 					callback null, projects.map((project) -> project.project_id)
 				).error callback
+		dbQueue.queue.push(job, callback)
+
 
 logger.log {EXPIRY_TIMEOUT: ProjectPersistenceManager.EXPIRY_TIMEOUT}, "project assets kept timeout"

services/clsi/app/coffee/UrlCache.coffee

@@ -1,4 +1,5 @@
 db = require("./db")
+dbQueue = require "./DbQueue"
 UrlFetcher = require("./UrlFetcher")
 Settings = require("settings-sharelatex")
 crypto = require("crypto")
@@ -6,15 +7,6 @@ fs = require("fs")
 logger = require "logger-sharelatex"
 async = require "async"
 
-queue = async.queue((task, cb)->
-	console.log("running task")
-	task(cb)
-, 1)
-
-console.log("hi there queue")
-queue.drain = ()->
-    console.log('HI all items have been processed')
-
 module.exports = UrlCache =
 	downloadUrlToFile: (project_id, url, destPath, lastModified, callback = (error) ->) ->
 		UrlCache._ensureUrlIsInCache project_id, url, lastModified, (error, pathToCachedUrl) =>
@@ -108,7 +100,7 @@ module.exports = UrlCache =
 			db.UrlCache.find(where: { url: url, project_id: project_id })
 				.then((urlDetails) -> cb null, urlDetails)
 				.error cb
-		queue.push job, callback
+		dbQueue.queue.push job, callback
 
 	_updateOrCreateUrlDetails: (project_id, url, lastModified, callback = (error) ->) ->
 		job = (cb)->
@@ -121,7 +113,7 @@ module.exports = UrlCache =
 							.error(cb)
 				)
 				.error cb
-		queue.push(job, callback)
+		dbQueue.queue.push(job, callback)
 
 	_clearUrlDetails: (project_id, url, callback = (error) ->) ->
 		job = (cb)->
@@ -129,7 +121,7 @@ module.exports = UrlCache =
 			db.UrlCache.destroy(where: {url: url, project_id: project_id})
 				.then(() -> cb null)
 				.error cb
-		queue.push(job, callback)
+		dbQueue.queue.push(job, callback)
 
 
 	_findAllUrlsInProject: (project_id, callback = (error, urls) ->) ->
@@ -141,7 +133,7 @@ module.exports = UrlCache =
 						cb null, urlEntries.map((entry) -> entry.url)
 				)
 				.error cb
-		queue.push(job, callback)
+		dbQueue.queue.push(job, callback)