Compatibility with kamal

[navidemad]

Hi, I’m migrating an I/O-bound application from Puma to Falcon.
I’ve followed the official guide locally, but I’m wondering if there’s anything specific that needs to be configured in Kamal for deployment. Also i am using Net::HTTP to make my HTTP calls, should i move to Async::HTTP ?

config/deploy.yml:

  proxy:
  ssl: true
  host: foo.bar.fr
  app_port: 3000

falcon.rb:

#!/usr/bin/env -S falcon host
# frozen_string_literal: true

require "falcon/environment/rack"

hostname = File.basename(__dir__)
port = ENV["PORT"] || 3000

service hostname do
  include Falcon::Environment::Rack

  # By default, Falcon uses Etc.nprocessors to set the count, which is likely incorrect on shared hosts like Heroku.
  # Review the following for guidance about how to find the right value for your app:
  # https://help.heroku.com/88G3XLA6/what-is-an-acceptable-amount-of-dyno-load
  # https://devcenter.heroku.com/articles/deploying-rails-applications-with-the-puma-web-server#workers
  count ENV.fetch("WEB_CONCURRENCY", 1).to_i

  # If using count > 1 you may want to preload your app to reduce memory usage and increase performance:
  # This file will be loaded in the main process before forking.
  preload "preload.rb"

  cache false
  verbose true

  endpoint Async::HTTP::Endpoint.parse("http://0.0.0.0:#{port}")
end

Dockerfile:
CMD ["bundle", "exec", "falcon", "host"]

bin/docker-entrypoint:

#!/bin/bash -e

# If running the rails server then create or migrate existing database
if [ "${@: -4:1}" == "bundle" ] && [ "${@: -3:1}" == "exec" ] && [ "${@: -2:1}" == "falcon" ] && [ "${@: -1:1}" == "host" ]; then
  ./bin/rails db:prepare
fi

exec "${@}"

Thanks

[ioquatix]

This looks fine to me, but it did make me consider why port = ... is not in the service environment. So I've updated the documentation and recommend you make the change too:

#!/usr/bin/env -S falcon host
# frozen_string_literal: true

require "falcon/environment/rack"

hostname = File.basename(__dir__)

service hostname do
  include Falcon::Environment::Rack

  # By default, Falcon uses Etc.nprocessors to set the count, which is likely incorrect on shared hosts like Heroku.
  # Review the following for guidance about how to find the right value for your app:
  # https://help.heroku.com/88G3XLA6/what-is-an-acceptable-amount-of-dyno-load
  # https://devcenter.heroku.com/articles/deploying-rails-applications-with-the-puma-web-server#workers
  count ENV.fetch("WEB_CONCURRENCY", 1).to_i

  # If using count > 1 you may want to preload your app to reduce memory usage and increase performance:
  # This file will be loaded in the main process before forking.
  preload "preload.rb"

  cache false
  verbose true

  port {ENV.fetch("PORT", 3000).to_i}
  endpoint {Async::HTTP::Endpoint.parse("http://0.0.0.0:#{port}")}
end

(The last two port and endpoint lines are changed).