1 files changed, 43 insertions, 9 deletions
diff --git a/config/puma.rb b/config/puma.rb
index 49f4b974d..e8212125f 100644
--- a/config/puma.rb
+++ b/config/puma.rb
@@ -1,13 +1,47 @@
-workers Integer(ENV['WEB_CONCURRENCY'] || 2)
-threads_count = Integer(ENV['MAX_THREADS'] || 5)
+# 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.
+#
+threads_count = ENV.fetch("MAX_THREADS") { 5 }.to_i
 threads threads_count, threads_count
 
-preload_app!
+# Specifies the `port` that Puma will listen on to receive requests, default is 3000.
+#
+port        ENV.fetch("PORT") { 3000 }
 
-rackup      DefaultRackup
-port        ENV['PORT']     || 3000
-environment ENV['RACK_ENV'] || 'development'
+# Specifies the `environment` that Puma will run in.
+#
+environment ENV.fetch("RAILS_ENV") { "development" }
 
-on_worker_boot do
-  ActiveRecord::Base.establish_connection
-end
+# Specifies the number of `workers` to boot in clustered mode.
+# Workers are forked webserver processes. If using threads and workers together
+# the concurrency of the application would be max `threads` * `workers`.
+# Workers do not work on JRuby or Windows (both of which do not support
+# processes).
+#
+workers ENV.fetch("WEB_CONCURRENCY") { 2 }
+
+# Use the `preload_app!` method when specifying a `workers` number.
+# This directive tells Puma to first boot the application and load code
+# before forking the application. This takes advantage of Copy On Write
+# process behavior so workers use less memory. If you use this option
+# you need to make sure to reconnect any threads in the `on_worker_boot`
+# block.
+#
+# preload_app!
+
+# The code in the `on_worker_boot` will be called if you are using
+# clustered mode by specifying a number of `workers`. After each worker
+# process is booted this block will be run, if you are using `preload_app!`
+# option you will want to use this block to reconnect to any threads
+# or connections that may have been created at application boot, Ruby
+# cannot share connections between processes.
+#
+# on_worker_boot do
+#   ActiveRecord::Base.establish_connection if defined?(ActiveRecord)
+# end
+
+# Allow puma to be restarted by `rails restart` command.
+plugin :tmp_restart