hoshinotsuyoshi and nateberkopec `ps -p` will check correctly whether $PID exists (#1545)
It is appropriate to use `ps -p` in that place.

Under certain conditions, existing code ``[ "`ps -A -o pid=
| grep -c $PID`" -eq 0 ]`` may behave incorrectly.

For example, if the content of $PID happens to be a short string
(such as `199`), and another process includes the string
(process such as `2199`), then unfortunately `grep -c` will return
positive number even if `199` is not running.
Latest commit 9aea96e Mar 28, 2018

README.md

Puma daemon service

Deprecatation Warning : init.d was replaced by systemd since Debian 8 and Ubuntu 16.04, you should look into /docs/systemd unless you are on an older OS.

Init script to manage multiple Puma servers on the same box using start-stop-daemon.

Installation

# Copy the init script to services directory 
sudo cp puma /etc/init.d
sudo chmod +x /etc/init.d/puma

# Make it start at boot time. 
sudo update-rc.d -f puma defaults

# Copy the Puma runner to an accessible location
sudo cp run-puma /usr/local/bin
sudo chmod +x /usr/local/bin/run-puma

# Create an empty configuration file
sudo touch /etc/puma.conf

Managing the jungle

Puma apps are held in /etc/puma.conf by default. It's mainly a CSV file and every line represents one app. Here's the syntax:

app-path,user,config-file-path,log-file-path,environment-variables

You can add an instance by editing the file or running the following command:

sudo /etc/init.d/puma add /path/to/app user /path/to/app/config/puma.rb /path/to/app/log/puma.log

The config and log paths, as well as the environment variables, are optional parameters and default to:

  • config: /path/to/app/config/puma.rb
  • log: /path/to/app/log/puma.log
  • environment: (empty)

Multiple environment variables need to be separated by a semicolon, e.g.

FOO=1;BAR=2

To remove an app, simply delete the line from the config file or run:

sudo /etc/init.d/puma remove /path/to/app

The command will make sure the Puma instance stops before removing it from the jungle.

Assumptions

  • The script expects a temporary folder named /path/to/app/tmp/puma to exist. Create it if it's not there by default. The pid and state files should live there and must be called: tmp/puma/pid and tmp/puma/state. You can change those if you want but you'll have to adapt the script for it to work.

  • Here's what a minimal app's config file should have:

pidfile "/path/to/app/tmp/puma/pid"
state_path "/path/to/app/tmp/puma/state"
activate_control_app