How do I use puma's configuration file?

Question

I was following this guide it documents the puma.rb file that is stored inside the app's config directory.

The guide is a bit flakey, but here's what I assume the puma.rb file does. Instead of running crazy commands such as this to get puma running on a specified socket:

bundle exec puma -e production -b unix:///var/run/my_app.sock

You can just specify the port, pid, session and other parameters in the puma.rb file like this:

rails_env = ENV['RAILS_ENV'] || 'production'

threads 4,4

bind  "/home/starkers/Documents/alpha/tmp/socket"
pidfile "/home/starkers/Documents/alpha/tmp/pid"
state_path "/home/starkers/Documents/alpha/tmp/state"

activate_control_app

And then you could cd into the app's root and run a simple command like

'puma'

and the parameters set in puma.rb would be followed. Unfortunately that doesn't seem to work for me.

At least, I ran puma inside the root of a tiny test app, and no .sock file appeared in /home/starkers/Documents/alpha/tmp/sockets so does that mean it isn't working?

How do I get this working? I am on a local development machine, so could that cause this error somehow? Is there a parameter I need to pass in when running

puma ?

Answer 1

I was also stuck trying to find documentation on the config file for puma but I did find the all-in-one config.ru file useful. I've formatted it here for future reference:

# The directory to operate out of.
# The default is the current directory.

directory '/u/apps/lolcat'

# Load “path” as a rackup file.
# The default is “config.ru”.

rackup '/u/apps/lolcat/config.ru'

# Set the environment in which the rack's app will run. The value must be a string.
# The default is “development”.

environment 'production'

# Daemonize the server into the background. Highly suggest that
# this be combined with “pidfile” and “stdout_redirect”.
# The default is “false”.

daemonize
daemonize false

# Store the pid of the server in the file at “path”.

pidfile '/u/apps/lolcat/tmp/pids/puma.pid'

# Use “path” as the file to store the server info state. This is
# used by “pumactl” to query and control the server.

state_path '/u/apps/lolcat/tmp/pids/puma.state'

# Redirect STDOUT and STDERR to files specified. The 3rd parameter
# (“append”) specifies whether the output is appended, the default is
# “false”.

stdout_redirect '/u/apps/lolcat/log/stdout', '/u/apps/lolcat/log/stderr'
stdout_redirect '/u/apps/lolcat/log/stdout', '/u/apps/lolcat/log/stderr', true

# Disable request logging.
# The default is “false”.

quiet

# Configure “min” to be the minimum number of threads to use to answer
# requests and “max” the maximum.
# The default is “0, 16”.

threads 0, 16

# Bind the server to “url”. “tcp://”, “unix://” and “ssl://” are the only
# accepted protocols.
# The default is “tcp://0.0.0.0:9292”.

bind 'tcp://0.0.0.0:9292'
bind 'unix:///var/run/puma.sock'
bind 'unix:///var/run/puma.sock?umask=0777'
bind 'ssl://127.0.0.1:9292?key=path_to_key&cert=path_to_cert'

# Listens on port 7001
# The default is 9292
port 7001

# Instead of “bind 'ssl://127.0.0.1:9292?key=path_to_key&cert=path_to_cert'” you
# can also use the “ssl_bind” option.

 ssl_bind '127.0.0.1', '9292', { key: path_to_key, cert: path_to_cert }

# Code to run before doing a restart. This code should
# close log files, database connections, etc.

# This can be called multiple times to add code each time.

on_restart do
  puts 'On restart...'
end

# Command to use to restart puma. This should be just how to
# load puma itself (ie. 'ruby -Ilib bin/puma'), not the arguments
# to puma, as those are the same as the original process.

restart_command '/u/app/lolcat/bin/restart_puma'

# === Cluster mode ===

# How many worker processes to run.
# The default is “0”.

workers 2

# Code to run when a worker boots to setup the process before booting
# the app.
# This can be called multiple times to add hooks.

on_worker_boot do
  puts 'On worker boot...'
end

# === Puma control rack application ===

# Start the puma control rack application on “url”. This application can
# be communicated with to control the main server. Additionally, you can
# provide an authentication token, so all requests to the control server
# will need to include that token as a query parameter. This allows for
# simple authentication.

# Check out https://github.com/puma/puma/blob/master/lib/puma/app/status.rb
# to see what the app has available.

activate_control_app 'unix:///var/run/pumactl.sock'
activate_control_app 'unix:///var/run/pumactl.sock', { auth_token: '12345' }
activate_control_app 'unix:///var/run/pumactl.sock', { no_token: true }

Those settings would then go in a ruby file (e.g. config/puma.rb) and then as Starkers says, you can run it with

puma -C config/puma.rb

Answer 2

Update: The original answer is no longer correct for Puma versions since 2019: Puma added a fallback mechanism, so both locations are checked now. ( https://github.com/puma/puma/pull/1885)

Puma first looks for configuration at config/puma/<environment_name>.rb, and then falls back to config/puma.rb.

Outdated answer:

If there is an environment defined - which is the case in your example - the configuration file is read from config/puma/[environment].rb and not config/puma.rb.

Just move your config/puma.rb to config/puma/production.rb and it should work.

Read the Puma documentation for more details: Configuration file

Answer 3

This will work:

puma -C config/puma.rb

Answer 4

You need to tell puma where to find your rackup file you can do it by putting this in your config:

rackup DefaultRackup

It looks like a fix for this is merged into master: https://github.com/puma/puma/pull/271