linux services systemd

_systemd.txt

# list all services
sudo systemctl --type=service | tee

# work with particular service
# status / start / stop / restart
sudo systemctl status app | tee

# see service log
sudo journalctl -u app.service

# if things go south
sudo systemctl daemon-reload
sudo systemctl reset-failed

app-puma.service

# /etc/systemd/system/app-puma.service

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

[Service]
Type=simple
User=deployer
WorkingDirectory=/home/deployer/app
ExecStart=/home/deployer/.rbenv/shims/puma -C /home/deployer/app/config/puma.rb
PIDFile=/home/deployer/app/tmp/puma.pid
Restart=always

[Install]
WantedBy=multi-user.target

caddy.service

# caddy.service
# /lib/systemd/system/caddy.service
# See https://caddyserver.com/docs/install for instructions.

[Unit]
Description=Caddy
Documentation=https://caddyserver.com/docs/
After=network.target network-online.target
Requires=network-online.target

[Service]
Type=notify
User=caddy
Group=caddy
ExecStart=/usr/bin/caddy run --environ --config /etc/caddy/Caddyfile
ExecReload=/usr/bin/caddy reload --config /etc/caddy/Caddyfile
TimeoutStopSec=5s
LimitNOFILE=1048576
LimitNPROC=512
PrivateTmp=true
ProtectSystem=full
AmbientCapabilities=CAP_NET_BIND_SERVICE

[Install]
WantedBy=multi-user.target

Caddyfile

# https://caddy.community/t/serving-tens-of-thousands-of-domains-over-https-with-caddy/11179

{
  admin off

  # on_demand_tls {
  #  ask http://localhost:3000
  #  interval 2m
  #  burst 5
  # }
}

(static) {
  @static {
    path /assets/*
    path *.ico *.css *.js *.gif *.jpg *.jpeg *.png *.svg *.woff *.woff2 *.json
  }

  header @static Cache-Control max-age=5184000
}

:443 {
  encode gzip

  import static

  tls {
    on_demand
  }

  route {
    file_server /assets/* {
      root /home/deployer/app/public
    }
    reverse_proxy  http://localhost:3000
  }
}

config_puma.rb

# set app root
Dir.chdir File.expand_path("../..", __FILE__)

# load RACK_ENV
require 'dotenv'
Dotenv.load

require 'bundler/setup'
Bundler.require

plugin          :tmp_restart # restart on touch of tmp/restart.txt
port            3000
log_requests    false
nakayoshi_fork  true
pidfile         './tmp/puma.pid'
state_path      './tmp/puma.state'

# activate_control_app('tcp://127.0.0.1:9000', no_token: true)

if ENV['RACK_ENV'] == 'production'
  stdout_redirect './log/puma.log', './log/puma_errros.log'
  environment 'production'
  threads     32, 32

  # this kills ruby Sequel and producess erros
  # https://stackoverflow.com/a/22100819/254915
  # preload_app!
  # and this must be 0
  workers 0

  # restart if there is no response on /ok
  Thread.new do
    loop do
      sleep 10

      unless `curl -si -m 5 http://localhost:3000/ok`.include?('200 OK')
        Logger.new('log/app_boot.log').error 'http://localhost:3000/ok fail, restarting'
        `touch tmp/restart.txt`
      end
    end
  end
end