new worker-options: exclude_queues and eval_qeues

One can explicitly exclude queues by name (see collectiveidea#789) or even give an
argument through, for eval with where.

lib/delayed/command.rb

@@ -70,6 +70,14 @@ def initialize(args) # rubocop:disable MethodLength
         opt.on('--queue=queue', 'Specify which queue DJ must look up for jobs') do |queue|
           @options[:queues] = queue.split(',')
         end
+        opt.on('--exclude_queues=queues', 'Specify which queues DJ must NOT look up for jobs') do |exclude_queues|
+          @options[:exlude_queues] = exclude_queues.split(',')
+        end
+        opt.on('--eval_queues=evalstring', "Specify a string, which will be eval'ed to where() while lookup. E.g. \"['created_at < ',2.days.ago]\"") do |eval_queues|
+          # this will fail (throwing an exception), if option eval_queues is not a valid argument to eval or where
+          Delayed::Job.where(eval(eval_queues)).any?
+          @options[:eval_queues] = eval_queues
+        end
         opt.on('--pool=queue1[,queue2][:worker_count]', 'Specify queues and number of workers for a worker pool') do |pool|
           parse_worker_pool(pool)
         end

lib/delayed/worker.rb

@@ -15,6 +15,8 @@ class Worker # rubocop:disable ClassLength
     DEFAULT_DEFAULT_PRIORITY = 0
     DEFAULT_DELAY_JOBS       = true
     DEFAULT_QUEUES           = []
+    DEFAULT_EXCLUDE_QUEUES   = []
+    DEFAULT_EVAL_QUEUES      = nil
     DEFAULT_READ_AHEAD       = 5
 
     cattr_accessor :min_priority, :max_priority, :max_attempts, :max_run_time,
@@ -25,6 +27,10 @@ class Worker # rubocop:disable ClassLength
     # Named queue into which jobs are enqueued by default
     cattr_accessor :default_queue_name
 
+    # Named queues to exclude
+    cattr_accessor :exclude_queues, :eval_queues
+
+
     cattr_reader :backend
 
     # name_prefix is ignored if name is set directly
@@ -38,6 +44,8 @@ def self.reset
       self.default_priority  = DEFAULT_DEFAULT_PRIORITY
       self.delay_jobs        = DEFAULT_DELAY_JOBS
       self.queues            = DEFAULT_QUEUES
+      self.exclude_queues    = DEFAULT_EXCLUDE_QUEUES
+      self.eval_queues       = DEFAULT_EVAL_QUEUES
       self.read_ahead        = DEFAULT_READ_AHEAD
       @lifecycle             = nil
     end
@@ -125,7 +133,7 @@ def initialize(options = {})
       @quiet = options.key?(:quiet) ? options[:quiet] : true
       @failed_reserve_count = 0
 
-      [:min_priority, :max_priority, :sleep_delay, :read_ahead, :queues, :exit_on_complete].each do |option|
+      [:min_priority, :max_priority, :sleep_delay, :read_ahead, :queues, :exit_on_complete, :exclude_queues, :eval_queues].each do |option|
         self.class.send("#{option}=", options[option]) if options.key?(option)
       end