Added ability set the size of dynos when scaling

Author: raldred

README.md

@@ -106,6 +106,18 @@ heroku config:add WORKLESS_WORKERS_RATIO=50
 
 In this example, it will scale up to a maximum of 10 workers, firing up 1 worker for every 50 jobs on the queue. The minimum will be 0 workers, but you could set it to a higher value if you want.
 
+## Worker size
+
+By default heroku will scale using standard-1x dynos, if you wish to use a different pro dyno size use the following config variable:
+
+<pre>
+heroku config:add WORKLESS_WORKER_SIZE=performance-m
+</pre>
+
+Possible values for [dyno size](https://devcenter.heroku.com/articles/dyno-types)
+
+Note: This will not work for Hobby dynos, switch to Professional to support configuring dyno size
+
 ## How does Workless work?
 
 - `Delayed::Workless::Scaler` is mixed into the `Delayed::Job` class, which adds a bunch of callbacks to it.

lib/workless/scalers/heroku.rb

@@ -11,6 +11,7 @@ class Heroku < Base
         def self.up
           return unless workers_needed > min_workers && workers < workers_needed
           updates = { "quantity": workers_needed }
+          updates[:size] = worker_size if worker_size
           client.formation.update(ENV['APP_NAME'], 'worker', updates)
         end
 
@@ -29,6 +30,7 @@ def self.workers
         # ENV['WORKLESS_WORKERS_RATIO']
         # ENV['WORKLESS_MAX_WORKERS']
         # ENV['WORKLESS_MIN_WORKERS']
+        # ENV['WORKLESS_WORKER_SIZE']
         #
         def self.workers_needed
           [[(jobs.count.to_f / workers_ratio).ceil, max_workers].min, min_workers].max
@@ -49,6 +51,10 @@ def self.max_workers
         def self.min_workers
           ENV['WORKLESS_MIN_WORKERS'].present? ? ENV['WORKLESS_MIN_WORKERS'].to_i : 0
         end
+
+        def self.worker_size
+          ENV['WORKLESS_WORKER_SIZE'].present? ? ENV['WORKLESS_WORKER_SIZE'] : nil
+        end
       end
     end
   end

spec/workless/scalers/heroku_spec.rb

@@ -22,6 +22,18 @@
         Delayed::Workless::Scaler::Heroku.client.formation.should_receive(:update).once.with(ENV['APP_NAME'], 'worker', updates)
         Delayed::Workless::Scaler::Heroku.up
       end
+
+      context 'with WORKLESS_WORKER_SIZE' do
+        before do
+          ENV['WORKLESS_WORKER_SIZE'] = 'performance-l'
+        end
+
+        it 'should set the workers size to WORKLESS_WORKER_SIZE' do
+          updates = { "quantity": 1, "size": "performance-l" }
+          Delayed::Workless::Scaler::Heroku.client.formation.should_receive(:update).once.with(ENV['APP_NAME'], 'worker', updates)
+          Delayed::Workless::Scaler::Heroku.up
+        end
+      end
     end
 
     context 'with workers' do