How to deploy Ruby (Sinatra Framework) using Apache with Puma on Ubuntu?

Question

I am running an Ubuntu 22.04 server on Linode and trying to deploy a simple Sinatra app using Apache with Puma, but currently, I am only able to display the index page, so I believe I am missing a simple step. I'm not sure how to connect Puma to Apache, so there is probably something related to that that I am missing. Here are the key files:

/var/www/example.com/web.rb

require 'sinatra'

get '/' do
  "Hello World"
end

/var/www/example.com/config/puma.rb

workers 2
threads 5, 5

preload_app!

port        5000
environment 'development'

/etc/apache2/sites-available/example.conf

<VirtualHost *:80>
     ServerAdmin info@example.com
     ServerName sinatra.example.com

     DocumentRoot /var/www/example.com

     <Directory /var/www/example.com>
          DirectoryIndex web.rb
          Allow from all
     </Directory>

     ErrorLog /var/www/example.com/logs/errors.log
     CustomLog /var/www/example.com/logs/access.log combined

     RewriteEngine on
     RewriteCond %{SERVER_NAME} =sinatra.example.com
     RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [END,NE,R=permanent]
</VirtualHost>

I have then run these commands without issue:

bundle install a2ensite systemctl reload apache2

Answer 1

You need to set up a reverse proxy (as @konstantin-strukov mentioned). Here is the full list of files that I set up and the commands I ran (not including installing apache and ruby), so that there is no ambiguity.

/var/www/example/web.rb

require 'sinatra'

get '/' do
  "Hello World"
end

/var/www/example/Procfile

web: bundle exec puma -C config/puma.rb

/var/www/example/GEMFILE

source 'http://rubygems.org'
ruby '3.0.4'
gem 'sinatra', '~>2'
gem 'puma', '~>5'

Note: Sinatra recently released a 3.0.0 version and Puma released a 6.0.0 and this caused conflicts with Rack, so I needed to use the previous version to get it to work.

/var/www/example/config.ru

require './web'
run Sinatra::Application

/var/www/example/config/puma.rb

workers 2
threads 1, 2

preload_app!

port        5000
environment "development"

app_dir = File.expand_path("../..", __FILE__)
bind "unix://#{app_dir}/tmp/puma/puma.sock"
stdout_redirect "#{app_dir}/logs/puma.stdout.log", "#{app_dir}/logs/puma.stderr.log", true
pidfile "#{app_dir}/tmp/puma/pid"
state_path "#{app_dir}/tmp/puma/state"
directory "#{app_dir}/"
activate_control_app "unix://#{app_dir}/tmp/puma/pumactl.sock"
prune_bundler

/etc/apache2/sites-available/example.conf

<VirtualHost *:80>
     ServerAdmin info@example.com
     ServerName sinatra.example.com
     ProxyRequests Off
     <Proxy *>
        Order Allow,Deny
        Allow from all
     </Proxy>
     ProxyPass / http://localhost:5000/
     ProxyPassReverse / http://localhost:5000/
     ProxyVia On

     DocumentRoot /var/www/example

     <Directory /var/www/example>
          DirectoryIndex web.rb
          Allow from all
     </Directory>

     ErrorLog /var/www/example/logs/errors.log
     CustomLog /var/www/example/logs/access.log combined

     RewriteEngine on
     RewriteCond %{SERVER_NAME} =sinatra.example.com
     RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [END,NE,R=permanent]
</VirtualHost>

/etc/systemd/system/puma.service

[Unit]
Description=Puma HTTP Server
After=network.target
Requires=puma.socket

[Service]
Type=notify
WatchdogSec=10
WorkingDirectory=/var/www/example
ExecStart=/usr/local/bin/puma -C /var/www/example/config/puma.rb
Restart=always

[Install]
WantedBy=multi-user.target

/etc/systemd/system/puma.socket

[Unit]
Description=Puma HTTP Server Accept Sockets

[Socket]
ListenStream=0.0.0.0:5000

# Socket options matching Puma defaults
NoDelay=true
ReusePort=true
Backlog=1024

[Install]
WantedBy=sockets.target

1. cd /var/www/example

2. bundle install

3. mkdir /var/www/example/logs

4. mkdir /var/www/example/tmp

5. mkdir /var/www/example/tmp/puma

6. chmod 777 /var/www/example/logs

7. chmod 755 /var/www/example/tmp

8. chmod 755 /var/www/example/tmp/puma

9. a2ensite example

10. a2enmod

    proxy proxy_ajp proxy_http rewrite deflate headers proxy_balancer proxy_connect proxy_html

11. systemctl daemon-reload

12. systemctl enable puma.service

13. systemctl enable puma.socket

14. systemctl start puma.socket

15. systemctl start puma.service

16. systemctl reload apache2