loosen puma version and update config as in Rails 8

Gemfile

@@ -14,7 +14,7 @@ gem "sprockets-rails"
 gem "pg", "~> 1.1"
 
 # Use the Puma web server [https://github.com/puma/puma]
-gem "puma", "~> 6.4"
+gem "puma"
 
 # Use JavaScript with ESM import maps [https://github.com/rails/importmap-rails]
 gem "importmap-rails"

Gemfile.lock

@@ -258,7 +258,7 @@ GEM
     net-smtp (0.4.0.1)
       net-protocol
     netrc (0.11.0)
-    nio4r (2.7.0)
+    nio4r (2.7.1)
     nokogiri (1.16.3-arm64-darwin)
       racc (~> 1.4)
     nokogiri (1.16.3-x86_64-darwin)
@@ -479,7 +479,7 @@ DEPENDENCIES
   kaminari
   meta-tags
   pg (~> 1.1)
-  puma (~> 6.4)
+  puma
   rails (~> 7.0.8)
   rails-i18n
   rails_admin

config/puma.rb

@@ -1,43 +1,55 @@
-# 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
+# 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.
 
-# Specifies the `worker_timeout` threshold that Puma will use to wait before
-# terminating a worker in development environments.
+# Puma starts a configurable number of processes (workers) and each process
+# serves each request in a thread from an internal thread pool.
 #
-worker_timeout 3600 if ENV.fetch("RAILS_ENV", "development") == "development"
-
-# Specifies the `port` that Puma will listen on to receive requests; default is 3000.
+# The ideal number of threads per worker depends both on how much time the
+# application spends waiting for IO operations and on how much you wish to
+# to prioritize throughput over latency.
+#
+# As a rule of thumb, increasing the number of threads will increase how much
+# traffic a given process can handle (throughput), but due to CRuby's
+# Global VM Lock (GVL) it has diminishing returns and will degrade the
+# response time (latency) of the application.
+#
+# The default is set to 3 threads as it's deemed a decent compromise between
+# throughput and latency for the average Rails application.
 #
-port ENV.fetch("PORT") { 3000 }
+# 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", 3)
+threads threads_count, threads_count
 
 # Specifies the `environment` that Puma will run in.
-#
-environment ENV.fetch("RAILS_ENV") { "development" }
+rails_env = ENV.fetch("RAILS_ENV", "development")
+environment rails_env
 
-# Specifies the `pidfile` that Puma will use.
-# pidfile ENV.fetch("PIDFILE") { "tmp/pids/server.pid" }
+case rails_env
+when "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.
+  workers_count = Integer(ENV.fetch("WEB_CONCURRENCY", 1))
+  workers workers_count if workers_count > 1
 
-# Specifies the number of `workers` to boot in clustered mode.
-# Workers are forked web server 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 }
+  preload_app!
+when "development"
+  # Specifies a very generous `worker_timeout` so that the worker
+  # isn't killed by Puma when suspended by a debugger.
+  worker_timeout 3600
+end
 
-# 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.
-#
-# preload_app!
+# Specifies the `port` that Puma will listen on to receive requests; default is 3000.
+port ENV.fetch("PORT", 3000)
 
-# Allow puma to be restarted by `rails restart` command.
+# Allow puma to be restarted by `bin/rails restart` command.
 plugin :tmp_restart
+
+# Only use a pidfile when requested
+pidfile ENV["PIDFILE"] if ENV["PIDFILE"]