kamal/lib/mrsk/cli/app.rb

require "mrsk/cli/base"

class Mrsk::Cli::App < Mrsk::Cli::Base
  desc "boot", "Boot app on servers (or start them if they've already been booted)"
  def boot
    cli = self

    using_version(options[:version] || most_recent_version_available) do |version|
      MRSK.config.roles.each do |role|
        on(role.hosts) do |host|
          begin
            execute *MRSK.app.run(role: role.name)
          rescue SSHKit::Command::Failed => e
            if e.message =~ /already in use/
              error "Rebooting container with same version already deployed on #{host}"

              cli.stop
              cli.remove_container version

              execute *MRSK.app.run(role: role.name)
            else
              raise
            end
          end
        end
      end
    end
  end

  desc "reboot", "Reboot app on host (stop container, remove container, start new container with latest image)"
  def reboot
    old_version = current_running_version

    stop
    remove_container old_version
    boot
  end

  desc "start", "Start existing app on servers (use --version=<git-hash> to designate specific version)"
  def start
    on(MRSK.hosts) { execute *MRSK.app.start, raise_on_non_zero_exit: false }
  end
  
  desc "stop", "Stop app on servers"
  def stop
    on(MRSK.hosts) { execute *MRSK.app.stop, raise_on_non_zero_exit: false }
  end
  
  desc "details", "Display details about app containers"
  def details
    on(MRSK.hosts) { |host| puts_by_host host, capture_with_info(*MRSK.app.info) }
  end
  
  desc "exec [CMD]", "Execute a custom command on servers"
  option :method, aliases: "-m", default: "exec", desc: "Execution method: [exec] perform inside app container / [run] perform in new container / [ssh] perform over ssh"
  def exec(cmd)
    runner = \
      case options[:method]
      when "exec" then "exec"
      when "run"  then "run_exec"
      when "ssh"  then "exec_over_ssh"
      else raise "Unknown method: #{options[:method]}"
      end.inquiry

    if runner.exec_over_ssh?
      run_locally do
        info "Launching command on #{MRSK.primary_host}"
        exec MRSK.app.exec_over_ssh(cmd, host: MRSK.primary_host)
      end
    else
      on(MRSK.hosts) { |host| puts_by_host host, capture_with_info(*MRSK.app.send(runner, cmd)) }
    end
  end

  desc "console", "Start Rails Console on primary host (or specific host set by --hosts)"
  def console
    using_version(options[:version] || most_recent_version_available) do
      run_locally do
        if version
          info "Launching Rails console on #{MRSK.primary_host} [Version: #{version}]"
          exec MRSK.app.console(host: MRSK.primary_host)
        else
          error "No image available for #{MRSK.config.repository}"
        end
      end
    end
  end

  desc "bash", "Start a bash session on primary host (or specific host set by --hosts)"
  def bash
    run_locally do
      info "Launching bash session on #{MRSK.primary_host}"
      exec MRSK.app.bash(host: MRSK.primary_host)
    end
  end

  desc "runner [EXPRESSION]", "Execute Rails runner with given expression"
  def runner(expression)
    on(MRSK.hosts) { |host| puts_by_host host, capture_with_info(*MRSK.app.exec("bin/rails", "runner", "'#{expression}'")) }
  end

  desc "containers", "List all the app containers currently on servers"
  def containers
    on(MRSK.hosts) { |host| puts_by_host host, capture_with_info(*MRSK.app.list_containers) }
  end

  desc "images", "List all the app images currently on servers"
  def images
    on(MRSK.hosts) { |host| puts_by_host host, capture_with_info(*MRSK.app.list_images) }
  end

  desc "current", "Return the current running container ID"
  def current
    on(MRSK.hosts) { |host| puts_by_host host, capture_with_info(*MRSK.app.current_container_id) }
  end
  
  desc "logs", "Show lines from app on servers"
  option :since, aliases: "-s", desc: "Show logs since timestamp (e.g. 2013-01-02T13:23:37Z) or relative (e.g. 42m for 42 minutes)"
  option :lines, type: :numeric, aliases: "-n", desc: "Number of log lines to pull from each server"
  option :grep, aliases: "-g", desc: "Show lines with grep match only (use this to fetch specific requests by id)"
  option :follow, aliases: "-f", desc: "Follow logs on primary server (or specific host set by --hosts)"
  def logs
    # FIXME: Catch when app containers aren't running

    grep = options[:grep]

    if options[:follow]
      run_locally do
        info "Following logs on #{MRSK.primary_host}..."
        info MRSK.app.follow_logs(host: MRSK.primary_host, grep: grep)
        exec MRSK.app.follow_logs(host: MRSK.primary_host, grep: grep)
      end
    else
      since = options[:since]
      lines = options[:lines].presence || ((since || grep) ? nil : 100) # Default to 100 lines if since or grep isn't set

      on(MRSK.hosts) do |host|
        begin
          puts_by_host host, capture_with_info(*MRSK.app.logs(since: since, lines: lines, grep: grep))
        rescue SSHKit::Command::Failed
          puts_by_host host, "Nothing found"
        end
      end
    end
  end

  desc "remove", "Remove app containers and images from servers"
  def remove
    remove_containers
    remove_images
  end

  desc "remove_container [VERSION]", "Remove app container with given version from servers"
  def remove_container(version)
    on(MRSK.hosts) { execute *MRSK.app.remove_container(version: version) }
  end

  desc "remove_containers", "Remove all app containers from servers"
  def remove_containers
    on(MRSK.hosts) { execute *MRSK.app.remove_containers }
  end

  desc "remove_images", "Remove all app images from servers"
  def remove_images
    on(MRSK.hosts) { execute *MRSK.app.remove_images }
  end

  desc "current_version", "Shows the version currently running"
  def current_version
    on(MRSK.hosts) { |host| puts_by_host host, capture_with_info(*MRSK.app.current_running_version).strip }
  end

  private
    def using_version(new_version)
      if new_version
        begin
          old_version = MRSK.config.version
          MRSK.config.version = new_version
          yield new_version
        ensure
          MRSK.config.version = old_version
        end
      else
        yield MRSK.config.version
      end
    end

    def most_recent_version_available(host: MRSK.primary_host)
      version = nil
      on(host) { version = capture_with_info(*MRSK.app.most_recent_version_from_available_images).strip }
      version.presence
    end

    def current_running_version(host: MRSK.primary_host)
      version = nil
      on(host) { version = capture_with_info(*MRSK.app.current_running_version).strip }
      version.presence
    end
end