Merge pull request #149 from collectiveidea/dg/pi

Rough but working start to running on the pi

pi/Gemfile

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+source "https://rubygems.org"
+ruby "3.2.1"
+
+gem "action_cable_client"
+gem "json"
+gem "sd_notify"

pi/Gemfile.lock

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+GEM
+  remote: https://rubygems.org/
+  specs:
+    action_cable_client (3.1.0)
+      websocket-eventmachine-client (>= 1.2.0)
+    eventmachine (1.2.7)
+    json (2.6.3)
+    websocket (1.2.9)
+    websocket-eventmachine-base (1.2.0)
+      eventmachine (~> 1.0)
+      websocket (~> 1.0)
+      websocket-native (~> 1.0)
+    websocket-eventmachine-client (1.3.0)
+      websocket-eventmachine-base (~> 1.0)
+    websocket-native (1.0.0)
+
+PLATFORMS
+  arm64-darwin-21
+  armv7l-linux-eabihf
+
+DEPENDENCIES
+  action_cable_client
+  json
+
+RUBY VERSION
+   ruby 3.2.1p31
+
+BUNDLED WITH
+   2.4.7

pi/buildlight_listener.service

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+[Unit]
+Description=Buildlight Listener
+After=network.target
+
+[Service]
+Type=notify
+
+# If theprocess locks up, systemd's watchdog will restart it within seconds.
+WatchdogSec=60
+
+# Preferably configure a non-privileged user
+User=pi
+
+# The path to your application code root directory.
+# Also replace the "<YOUR_APP_PATH>" placeholders below with this path.
+# Example /home/username/myapp
+WorkingDirectory=/home/pi/listener
+
+# Helpful for debugging socket activation, etc.
+# Environment=PUMA_DEBUG=1
+
+# SystemD will not run puma even if it is in your path. You must specify
+# an absolute URL to puma. For example /usr/local/bin/puma
+# Alternatively, create a binstub with `bundle binstubs puma --path ./sbin` in the WorkingDirectory
+ExecStart=/home/pi/listener/listener.rb
+
+Restart=always
+
+[Install]
+WantedBy=multi-user.target

pi/listener.rb

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+#!/usr/local/bin/ruby
+
+require "bundler/setup"
+require "json"
+require "action_cable_client"
+require "sd_notify"
+
+if ENV["NOTIFY_SOCKET"]
+  $stdout.reopen "listener.log", "a"
+  $stderr.reopen "listener.log", "a"
+  $stdout.sync = true
+  $stderr.sync = true
+end
+
+class StopLight
+  RED_LED = "16"
+  YELLOW_LED = "15"
+  GREEN_LED = "14"
+  HOST = "buildlight.collectiveidea.com"
+  DEVICE_ID = "collectiveidea-office"
+
+  @red = true
+  @yellow = true
+  @green = true
+  @blink_state = true
+  @running = true
+
+  def self.startup
+    export_pin(RED_LED)
+    export_pin(YELLOW_LED)
+    export_pin(GREEN_LED)
+
+    trap_signals
+    SdNotify.ready
+    setup_watchdog
+    start_client
+  end
+
+  def self.set_colors(colors)
+    @red = colors["red"]
+    @yellow = colors["yellow"]
+    @green = colors["green"]
+    start_light_thread
+  end
+
+  def self.write_colors
+    write_color(RED_LED, @red)
+    write_color(YELLOW_LED, @yellow && @blink_state)
+    write_color(GREEN_LED, @green)
+  end
+
+  def self.write_color(pin, value)
+    File.write("/sys/class/gpio/gpio#{pin}/value", value ? "1" : "0")
+  end
+
+  def self.export_pin(pin)
+    File.write("/sys/class/gpio/export", pin) unless File.exist?("/sys/class/gpio/gpio#{pin}/value")
+  end
+
+  def self.start_light_thread
+    return if @started_light_thread
+
+    Thread.new do
+      loop do
+        start = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+        write_colors
+        @blink_state = !@blink_state
+        SdNotify.status("{red: #{@red}, yellow: #{@yellow}, green: #{@green}}")
+        sleep Process.clock_gettime(Process::CLOCK_MONOTONIC) - start + 1
+      end
+    end
+    @started_light_thread = true
+  end
+
+  def self.setup_watchdog
+    return unless SdNotify.watchdog?
+
+    usec = Integer(ENV["WATCHDOG_USEC"])
+
+    sec_f = usec / 1_000_000.0
+    # "It is recommended that a daemon sends a keep-alive notification message
+    # to the service manager every half of the time returned here."
+    ping_f = sec_f / 2
+
+    Thread.new do
+      puts "[#{Time.current}] Pinging systemd watchdog every #{ping_f.round(1)} sec"
+      loop do
+        sleep ping_f
+        SdNotify.watchdog
+      end
+    end
+  end
+
+  def self.start_client
+    params = {channel: "DeviceChannel", id: DEVICE_ID}
+    headers = {"ORIGIN" => "https://#{HOST}"}
+    EventMachine.run do
+      client = ActionCableClient.new("wss://#{HOST}/cable", params, true, headers)
+      client.connected { puts "[#{Time.current}] successfully connected." }
+      client.received do |message|
+        puts "[#{Time.current}] #{message["message"]["colors"]}"
+        set_colors(message["message"]["colors"])
+      end
+      client.disconnected { restart }
+    end
+  end
+
+  def self.trap_signals
+    Signal.trap("SIGTERM") { shutdown }
+    Signal.trap("SIGHUP") { shutdown }
+    Signal.trap("SIGINT") { shutdown }
+    Signal.trap("SIGUSR1") { restart }
+    Signal.trap("SIGUSR2") { restart }
+  end
+
+  def self.shutdown
+    SdNotify.stopping
+    @running = false
+    exit
+  end
+
+  def self.restart
+    return unless @running
+
+    puts "[#{Time.current}] restarting"
+    SdNotify.reloading
+    Kernel.exec(__FILE__)
+  end
+end
+
+StopLight.startup

pi/readme.txt

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+Load Raspberry Pi OS Lite (64 bit)
+
+sudo apt update
+sudo apt dist-upgrade
+sudo reboot
+
+sudo apt install libcurl4-openssl-dev git libreadline6-dev libssl-dev libyaml-dev libxml2-dev libxslt-dev autoconf ncurses-dev automake libtool bison
+
+wget https://cache.ruby-lang.org/pub/ruby/3.2/ruby-3.2.1.tar.gz
+tar xzf ruby-3.2.1.tar.gz
+cd ruby-3.2.1/
+./configure --prefix=/usr/local --enable-shared --disable-install-doc
+make -j 2
+sudo make install
+
+mkdir listener
+copy listener.rb Gemfile Gemfile.lock
+chmod +x listener.rb
+bundle config set --local path 'vendor'
+bundle install
+
+# Setup listener to load via systemd
+copy buildlight_listener.service to /etc/systemd/system/
+sudo systemctl daemon-reload
+sudo systemctl enable buildlight_listener.service
+sudo systemctl start buildlight_listener.service