Better Puma configuration + documentation for systemd unit

INSTALL.md

@@ -11,7 +11,7 @@ We are usually running Chexpire on typical POSIX servers like :
 - Linux Debian 9, Ruby 2.5.4, NodeJS 8.11 and MariaDB 10.1
 - macOS High Sierra, Ruby 2.5.4, NodeJS 10.2.1 and MariaDB 10.2
 
-It probably works on any system that supports Ruby >2.3, NodeJS >6 and MySQL >5.5. Feel free to report any unexpected incompatibilities.
+It probably works on any system that supports Ruby >= 2.5.4, NodeJS >= 6 and MySQL >= 5.5. Feel free to report any unexpected incompatibilities.
 
 If you use rbenv, chruby or RVM, you can set your prefered Ruby version in the `.ruby-version` file at the root of the project.
 
@@ -34,7 +34,7 @@ If you want to do manual installations, you can use our Wiki documentations for
 
 Execute `# bundle install` to install Ruby gems (including Rails itself).
 
-Execute `# yarn install` to install Javascript/NodeJS packages.
+Execute `# yarn install --check-files` to install Javascript/NodeJS packages.
 
 Depending on what is already installed on your OS or not, you might need to install a few system packages to be able to have everything working.
 
@@ -45,15 +45,21 @@ To use elliptic curve SSH keys, we need to have `libsodium` and its headers.
 * on macOS with Homebrew : `# brew install libsodium`.
 
 
-## Rails configuration
+## Application configuration
 
 After cloning this repository, you have to create and edit a few files for your local development/test configuration. Theses files will be ignored by git.
 
+### Environment variables
+
+A handful of settings can be set by environment variables. If you use Heroku-like platforms they offer a simple way to set them.
+
+If you use Rbenv, there is the `rbenv-vars` plugin. That is what we recommend on POSIX servers. You have to put an `.rbenv-vars` file at the root of the project. If you use Capistrano, put it in the shared directory and have it linked in the `current` directory at deploy time.
+
 ### Database configuration
 
 Create the file if missing : `cp config/database.example.yml config/database.yml`. If you change the settings in the `defaults` section it applies to the `development` and `test` sections. More information is available at "guides.rubyonrails.org":https://guides.rubyonrails.org/configuring.html#configuring-a-database
 
-Note that on Debian 9 with MariaDB, the database socket is at `/var/run/mysqld/mysqld.sock`, which is not the default in the configuration file.
+Note that on Debian 9+ with MariaDB, the database socket is at `/var/run/mysqld/mysqld.sock`, which is not the default in the configuration file.
 
 ### Rails secrets
 
@@ -113,3 +119,17 @@ You can use the `script/to_staging` and/or `script/to_production` scripts.
 * with `to_production` you deploy the `master` branch to production.
 
 On the remote servers – where the application will be deployed – you have to copy the configuration files just as you've just did for your development setup. The files has to go in the `shared/config/` directory, relative to your `deploy_to` path. They will be symlinked to the proper destination by Capistrano.
+If an `.rbenv-vars` file is found in the shared directory, it will be linked to help loading environment files (by Ruby via Rbenv, systemd…).
+
+### systemd
+
+If you want to use systemd to manage your Puma process, there are [a few different ways](https://github.com/puma/puma/blob/master/docs/systemd.md). We've prepared a systemd unit file (`config/deploy/puma-chexpire@.service`) but you can adjust to better suit your needs.
+
+If you deploy your application to `/home/chexpire_<environment>`, the systemd unit can be used as a template, for example : `puma-chexpire@production.service`. This template is compatible with systemd actions like `systemctl stop puma-chexpire@production.service` and also with Capistrano tasks like `cap production puma:stop`.
+
+To install the systemd unit :
+
+```
+$ cp config/deploy/puma-chexpire@.service /etc/systemd/system/puma-chexpire@.service
+$ systemctl enable puma-chexpire@<environment>.service
+```

config/deploy.rb

@@ -24,12 +24,16 @@ set :repo_url, "https://github.com/Evolix/chexpire.git"
 
 # Default value for :linked_files is []
 append :linked_files,
+  ".rbenv-vars",
   "config/chexpire.yml",
   "config/database.yml",
   "config/secrets.yml"
 
 # Default value for linked_dirs is []
 # append :linked_dirs, "log", "tmp/pids", "tmp/cache", "tmp/sockets", "public/system"
+append :linked_dirs,
+  "tmp/pids",
+  "tmp/sockets"
 
 # Default value for default_env is {}
 # set :default_env, { path: "/opt/ruby/bin:$PATH" }

config/deploy/puma-chexpire@.service

@@ -0,0 +1,21 @@
+[Unit]
+Description=Puma Server for Chexpire (%i)
+After=network.target
+
+[Service]
+Type=forking
+User=chexpire_%i
+EnvironmentFile=/home/chexpire_%i/www/current/.rbenv-vars
+Environment=RAILS_ENV=%i
+WorkingDirectory=/home/chexpire_%i/www/current/
+PIDFile=/home/chexpire_%i/www/shared/tmp/pids/puma.pid
+
+ExecStart=/home/chexpire_%i/.rbenv/bin/rbenv exec bundle exec puma -C /home/chexpire_%i/www/current/config/puma.rb --daemon
+ExecStop=/home/chexpire_%i/.rbenv/bin/rbenv exec bundle exec pumactl -F /home/chexpire_%i/www/current/config/puma.rb stop
+ExecReload=/home/chexpire_%i/.rbenv/bin/rbenv exec bundle exec pumactl -F /home/chexpire_%i/www/current/config/puma.rb phased-restart
+
+Restart=no
+RemainAfterExit=yes
+
+[Install]
+WantedBy=multi-user.target

config/puma.rb

@@ -8,31 +8,44 @@ 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
 
-# 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 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" }
+app_dir = File.expand_path("../..", __FILE__)
+directory app_dir
+shared_dir = "#{app_dir}/tmp"
 
-# 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 }
+if %w[production staging].member?(rails_env)
+  # Logging
+  stdout_redirect "#{app_dir}/log/puma.stdout.log", "#{app_dir}/log/puma.stderr.log", true
 
-# 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!
+  # Set master PID and state locations
+  pidfile "#{shared_dir}/pids/puma.pid"
+  state_path "#{shared_dir}/pids/puma.state"
+
+  # Change to match your CPU core count
+  workers ENV.fetch("WEB_CONCURRENCY") { 2 }
+
+  preload_app!
+
+  # Set up socket location and port
+  bind "unix://#{shared_dir}/sockets/puma.sock"
+  port ENV.fetch("PORT") { 3000 }
+
+  before_fork do
+    ActiveRecord::Base.connection_pool.disconnect!
+  end
 
-# Allow puma to be restarted by `rails restart` command.
-plugin :tmp_restart
+  on_worker_boot do
+    ActiveSupport.on_load(:active_record) do
+      db_url = ENV.fetch('DATABASE_URL')
+      # puts "puma: connecting to DB at #{db_url}"
+      ActiveRecord::Base.establish_connection(db_url)
+    end
+  end
+elsif rails_env == "development"
+  # Specifies the `port` that Puma will listen on to receive requests; default is 3000.
+  port   ENV.fetch("PORT") { 3000 }
+  plugin :tmp_restart
+end