Modernize puma configuration

config/puma.rb

@@ -1,44 +1,21 @@
-# This configuration file will be evaluated by Puma. The top-level methods that
-# are invoked here are part of Puma's configuration DSL. For more information
-# about methods provided by the DSL, see https://puma.io/puma/Puma/DSL.html.
-
-# Puma can serve each request in a thread from an internal thread pool.
-# The `threads` method setting takes two numbers: a minimum and maximum.
-# Any libraries that use thread pools should be configured to match
-# the maximum value specified for Puma. Default is set to 5 threads for minimum
-# and maximum; this matches the default thread size of Active Record.
-max_threads_count = ENV.fetch("RAILS_MAX_THREADS") { 5 }
-min_threads_count = ENV.fetch("RAILS_MIN_THREADS") { max_threads_count }
-threads min_threads_count, max_threads_count
-
-rails_env = ENV.fetch("RAILS_ENV") { "development" }
-
-if rails_env == "production"
-  # If you are running more than 1 thread per process, the workers count
-  # should be equal to the number of processors (CPU cores) in production.
-  #
-  # It defaults to 1 because it's impossible to reliably detect how many
-  # CPU cores are available. Make sure to set the `WEB_CONCURRENCY` environment
-  # variable to match the number of processors.
-  worker_count = Integer(ENV.fetch("WEB_CONCURRENCY") { 1 })
-  if worker_count > 1
-    workers worker_count
-  else
-    preload_app!
-  end
-end
-# Specifies the `worker_timeout` threshold that Puma will use to wait before
-# terminating a worker in development environments.
-worker_timeout 3600 if ENV.fetch("RAILS_ENV", "development") == "development"
+# Puma starts a configurable number of processes (workers) and each process
+# serves each request in a thread from an internal thread pool.
+#
+# You can control the number of workers using ENV["WEB_CONCURRENCY"]. You
+# should only set this value when you want to run 2 or more workers. The
+# default is already 1.
+#
+# Any libraries that use a connection pool or another resource pool should
+# be configured to provide at least as many connections as the number of
+# threads. This includes Active Record's `pool` parameter in `database.yml`.
+threads_count = ENV.fetch("RAILS_MAX_THREADS", 5)
+threads threads_count, threads_count
 
 # Specifies the `port` that Puma will listen on to receive requests; default is 3000.
-port ENV.fetch("PORT") { 3000 }
-
-# Specifies the `environment` that Puma will run in.
-environment rails_env
+port ENV.fetch("PORT", 3000)
 
 # Specifies the `pidfile` that Puma will use.
-pidfile ENV.fetch("PIDFILE") { "tmp/pids/server.pid" }
+pidfile ENV.fetch("PIDFILE", "tmp/pids/server.pid")
 
 # Allow puma to be restarted by `bin/rails restart` command.
 plugin :tmp_restart