--- title: Sidekiq Background Workers layout: framework_docs objective: Deploy Rails applications that run in multiple processes to one Fly application, like Sidekiq background jobs. order: 6 --- Rails applications commonly defer complex tasks that take a long to complete to a background worker to make web responses seem fast. This guide shows how to use [Sidekiq](https://github.com/mperham/sidekiq), a popular open-source Rails background job framework, to set up background workers, but it could be done with other great libraries like [Good Job](https://github.com/bensheldon/good_job), [Resque](https://github.com/resque/resque), [etc](https://www.ruby-toolbox.com/categories/Background_Jobs). ## Provision a Redis server Sidekiq depends on Redis to communicate between the Rails server process and the background workers. Follow the [Redis setup guide](/docs/upstash/redis/) to provision a Redis server and set a `REDIS_URL` within the Rails app. Be sure to set the `REDIS_URL` via a secret as demonstrated [here](/docs/rails/the-basics/configuration/#secret-variables). Verify the `REDIS_URL` is available to your Rails application before you continue by running: ```cmd fly ssh console -C "printenv REDIS_URL" ``` ```output REDIS_URL=redis://default:yoursecretpassword@my-apps-redis-host.internal:6379 ``` If you don't see `REDIS_URL` in the command above, Sidekiq won't be able to connect and process background jobs. ## Run multiple processes Most production Rails applications run background workers in a separate process. There's a few ways of accomplishing that on Fly that are [outlined in the multiple-processes](/docs/app-guides/multiple-processes) docs. The quickest way to run multiple processes in one region is via the `processes` directive in the `fly.toml` file. <aside class="callout"> The `[processes]` directive currently only works within a single Fly region. [Scaling a Rails application to multiple regions](/docs/rails/advanced-guides/multi-region) requires a different approach to running multiple processes. </aside> Add the following to the `fly.toml`: ```toml [processes] app = "bin/rails server" worker = "bundle exec sidekiq" ``` Then under the `[http_service]` directive, add `processes = ["app"]`. The configuration file should look something like this: ```toml [http_service] processes = ["app"] # this service only applies to the app process internal_port = 3000 force_https = true auto_stop_machines = true auto_start_machines = true min_machines_running = 0 ``` This associates the process with the service that Fly launches. ## Deploy and test Once multiple processes are configured in the `fly.toml` file, deploy them via: ```cmd fly deploy ``` If all goes well the application should launch with both `app` and `worker` processes. Be sure to run through the application and test features that kick-off background jobs. If you're having issues getting it working, run `fly logs` to see errors. ## Scaling Scaling up and down processes may be accomplished by running: ```cmd fly scale count app=3 worker=3 ``` To view the current state of the application's scale, run: ```cmd fly status ``` ```output App Name = my-rails-app Owner = personal Version = 41 Status = running Hostname = my-rails-app.fly.dev Instances ID PROCESS VERSION REGION DESIRED STATUS HEALTH CHECKS RESTARTS CREATED 15088508 worker 41 ord run running 0 34s ago 8789ef49 app 41 ord run running 1 total, 1 passing 0 2022-07-26T16:06:34Z c419942b app 41 ord run running 1 total, 1 passing 0 2022-07-26T16:05:52Z ea7af986 app 41 ord run running 1 total, 1 passing 0 2022-07-26T16:05:52Z d681c33d worker 41 ord run running 0 2022-07-26T15:42:30Z d8d8dc08 worker 41 ord run running 0 2022-07-26T15:42:30Z ``` In this case, we can see that 3 worker processes and 3 app processes are running in the `ord` region.

fly ssh console -C "printenv REDIS_URL"

REDIS_URL=redis://default:yoursecretpassword@my-apps-redis-host.internal:6379

[processes]
app = "bin/rails server"
worker = "bundle exec sidekiq"

[http_service]
  processes = ["app"] # this service only applies to the app process
  internal_port = 3000
  force_https = true
  auto_stop_machines = true
  auto_start_machines = true
  min_machines_running = 0

fly deploy

fly scale count app=3 worker=3

fly status

App
  Name     = my-rails-app
  Owner    = personal
  Version  = 41
  Status   = running
  Hostname = my-rails-app.fly.dev

Instances
ID        PROCESS VERSION REGION  DESIRED STATUS  HEALTH CHECKS       RESTARTS  CREATED
15088508  worker  41      ord     run     running                     0         34s ago
8789ef49  app     41      ord     run     running 1 total, 1 passing  0         2022-07-26T16:06:34Z
c419942b  app     41      ord     run     running 1 total, 1 passing  0         2022-07-26T16:05:52Z
ea7af986  app     41      ord     run     running 1 total, 1 passing  0         2022-07-26T16:05:52Z
d681c33d  worker  41      ord     run     running                     0         2022-07-26T15:42:30Z
d8d8dc08  worker  41      ord     run     running                     0         2022-07-26T15:42:30Z