Adding env vars to configure worker

In order to make it easy to configure the worker component (set how many times
it should be respawned; if it should be spawned by this process or it will be
invoked elsewhere), couple optional env vars were added.

Author: nuxlli

Rakefile

@@ -46,7 +46,8 @@ desc "Work the delayed_job queue."
 task :work_jobs do
   Delayed::Job.delete_all
 
-  3.times do
+  worker_retry = Integer(ENV["WORKER_RETRY"] || 3)
+  worker_retry.times do
     Delayed::Worker.new(
       min_priority: ENV["MIN_PRIORITY"],
       max_priority: ENV["MAX_PRIORITY"]

app.json

@@ -23,6 +23,14 @@
     "ENFORCE_SSL": {
       "description": "Force all clients to connect over SSL",
       "value": "true"
+    },
+    "WORKER_EMBEDDED": {
+      "description": "Force worker threads to be spawned by main process",
+      "value": "true"
+    },
+    "WORKER_RETRY": {
+      "description": "Number of times to respawn the worker thread if it fails",
+      "value": "3"
     }
   },
   "addons": [

config/unicorn.rb

@@ -9,7 +9,7 @@
   # as there's no need for the master process to hold a connection
   ActiveRecord::Base.connection.disconnect! if defined?(ActiveRecord::Base)
 
-  @delayed_job_pid ||= spawn("bundle exec rake work_jobs")
+  @delayed_job_pid ||= spawn("bundle exec rake work_jobs") unless ENV["WORKER_EMBEDDED"] == "false"
 
   sleep 1
 end