feat(server): enable work queue priority levels

Most of the work for this was done in #363, just wrapping it up.

server/controllers/visits.js

@@ -44,7 +44,7 @@ var visitsController = {
     var p = request.payload;
     var userId = request.auth.credentials;
 
-    var created = visitsController._create(userId, p.url, p.title, p.visitedAt, p.visitId);
+    var created = visitsController._create(userId, p.url, p.title, p.visitedAt, p.visitId, p.priority);
     reply(visitsView.render(created));
   },
   bulk: function(request, reply) {
@@ -62,7 +62,6 @@ var visitsController = {
   },
   _create: function(userId, url, title, visitedAt, visitId, priority) {
     visitId = visitId || uuid.v4();
-    priority = priority || 'regular';
     var urlHash = crypto.createHash('sha1').update(url).digest('hex').toString();
     var data = {
       userId: userId,

server/work-queue/queue.js

@@ -120,7 +120,9 @@ _queue.on('job progress', onJobProgress);
 
 
 // TODO allow job creation to set priorities; we're setting priority here for the moment
-// opts := job data object
+// opts := { priority, data }
+// priority := 'low' | 'normal' | 'medium' | 'high' | 'critical'
+// data := data passed to the worker to run the job
 var exported = {
   enqueue: function(job, data, priority) {
     log.debug(job + '.called');
@@ -129,13 +131,13 @@ var exported = {
       .save();
   },
   createVisit: function(opts) {
-    exported.enqueue('createVisit', opts, 'high');
+    exported.enqueue('createVisit', opts.data, opts.priority || 'high');
   },
   extractPage: function(opts) {
-    exported.enqueue('extractPage', opts, 'medium');
+    exported.enqueue('extractPage', opts.data, opts.priority || 'medium');
   },
   sendWelcomeEmail: function(opts) {
-    exported.enqueue('sendWelcomeEmail', opts, 'low');
+    exported.enqueue('sendWelcomeEmail', opts.data, opts.priority || 'low');
   }
 };