Processing Groups is a way to set specific configurations, such as queues, concurrency, long polling per queue(s).

Given this configuration:

concurrency: 25
queues:
  - queue1
  - queue2
  - queue3

Shoryuken will fetch messages from queue1, then queue2, then queue3, then repeat. See Polling strategies for more information.

If you don't want to wait on fetching for queue1 to fetch for queue2, you can move them into separate groups:

groups:
  group1:
    concurrency: 10
    queues:
      - queue1
  group2:
    concurrency: 10
    delay: 10
    queues:
      - queue2

Is that all? No, it is not! If you want to process only one message at time for queue1, but keeping concurrency: 25 for queue2 and queue3:

concurrency: 25
queues:
  - queue2
  - queue3
groups:
  group1:
    concurrency: 1
    queues:
      - queue1

Note: If you want to make sure to process only one message at time for a given queue while running multiple Shoryuken processes, have a look at FIFO Queues.

groups:
  group1:
    polling_strategy: StrictPriority
    queues:
      - queue1
  group2:
    polling_strategy: WeightedRoundRobin # Default, declaration optional
    queues:
      - queue2

See Polling strategies.

# config/initializers/shoryuken.rb
Shoryuken.sqs_client_receive_message_opts[:group1] = { wait_time_seconds: 20 }

See Long Polling.