Class: SwitchTower::CLI

Inherits:
Object
  • Object
show all
Defined in:
lib/switchtower/cli.rb

Overview

The CLI class encapsulates the behavior of switchtower when it is invoked as a command-line utility. This allows other programs to embed ST and preserve it’s command-line semantics.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(args = ARGV) ⇒ CLI

Create a new CLI instance using the given array of command-line parameters to initialize it. By default, ARGV is used, but you can specify a different set of parameters (such as when embedded ST in a program):

require 'switchtower/cli'
SwitchTower::CLI.new(%w(-vvvv -r config/deploy -a update_code)).execute!

Note that you can also embed ST directly by creating a new Configuration instance and setting it up, but you’ll often wind up duplicating logic defined in the CLI class. The above snippet, redone using the Configuration class directly, would look like:

require 'switchtower'
require 'switchtower/cli'
config = SwitchTower::Configuration.new
config.logger_level = SwitchTower::Logger::TRACE
config.set(:password) { SwitchTower::CLI.password_prompt }
config.load "standard", "config/deploy"
config.actor.update_code

There may be times that you want/need the additional control offered by manipulating the Configuration directly, but generally interfacing with the CLI class is recommended.



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# File 'lib/switchtower/cli.rb', line 96

def initialize(args = ARGV)
  @args = args
  @options = { :verbose => 0, :recipes => [], :actions => [], :vars => {},
    :pre_vars => {} }

  OptionParser.new do |opts|
    opts.banner = "Usage: #{$0} [options] [args]"

    opts.separator ""
    opts.separator "Recipe Options -----------------------"
    opts.separator ""

    opts.on("-a", "--action ACTION",
      "An action to execute. Multiple actions may",
      "be specified, and are loaded in the given order."
    ) { |value| @options[:actions] << value }

    opts.on("-p", "--password [PASSWORD]",
      "The password to use when connecting. If the switch",
      "is given without a password, the password will be",
      "prompted for immediately. (Default: prompt for password",
      "the first time it is needed.)"
    ) { |value| @options[:password] = value }

    opts.on("-r", "--recipe RECIPE",
      "A recipe file to load. Multiple recipes may",
      "be specified, and are loaded in the given order."
    ) { |value| @options[:recipes] << value }

    opts.on("-s", "--set NAME=VALUE",
      "Specify a variable and it's value to set. This",
      "will be set after loading all recipe files."
    ) do |pair|
      name, value = pair.split(/=/, 2)
      @options[:vars][name.to_sym] = value
    end

    opts.on("-S", "--set-before NAME=VALUE",
      "Specify a variable and it's value to set. This",
      "will be set BEFORE loading all recipe files."
    ) do |pair|
      name, value = pair.split(/=/, 2)
      @options[:pre_vars][name.to_sym] = value
    end

    opts.separator ""
    opts.separator "Framework Integration Options --------"
    opts.separator ""

    opts.on("-A", "--apply-to DIRECTORY",
      "Create a minimal set of scripts and recipes to use",
      "switchtower with the application at the given",
      "directory. (Currently only works with Rails apps.)"
    ) { |value| @options[:apply_to] = value }

    opts.separator ""
    opts.separator "Miscellaneous Options ----------------"
    opts.separator ""

    opts.on("-h", "--help", "Display this help message") do
      puts opts
      exit
    end

    opts.on("-P", "--[no-]pretend",
      "Run the task(s), but don't actually connect to or",
      "execute anything on the servers. (For various reasons",
      "this will not necessarily be an accurate depiction",
      "of the work that will actually be performed.",
      "Default: don't pretend.)"
    ) { |value| @options[:pretend] = value }

    opts.on("-v", "--verbose",
      "Specify the verbosity of the output.",
      "May be given multiple times. (Default: silent)"
    ) { @options[:verbose] += 1 }

    opts.on("-V", "--version",
      "Display the version info for this utility"
    ) do
      require 'switchtower/version'
      puts "SwitchTower v#{SwitchTower::Version::STRING}"
      exit
    end

    opts.separator ""
    opts.separator <<-DETAIL.split(/\n/)
You can use the --apply-to switch to generate a minimal set of switchtower
scripts and recipes for an application. Just specify the path to the application
as the argument to --apply-to, like this:

  switchtower --apply-to ~/projects/myapp

You'll wind up with a sample deployment recipe in config/deploy.rb, some new
rake tasks in config/tasks, and a switchtower script in your script directory.

(Currently, --apply-to only works with Rails applications.)
DETAIL

    if args.empty?
      puts opts
      exit
    else
      opts.parse!(args)
    end
  end

  check_options!

  password_proc = Proc.new { self.class.password_prompt }

  if !@options.has_key?(:password)
    @options[:password] = password_proc
  elsif !@options[:password]
    @options[:password] = password_proc.call
  end
end

Instance Attribute Details

#args ⇒ Object (readonly)

The array of (unparsed) command-line options



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# File 'lib/switchtower/cli.rb', line 68

def args
  @args
end

#options ⇒ Object (readonly)

The hash of (parsed) command-line options



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# File 'lib/switchtower/cli.rb', line 71

def options
  @options
end

Class Method Details

.execute! ⇒ Object

Invoke switchtower using the ARGV array as the option parameters. This is what the command-line switchtower utility does.



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# File 'lib/switchtower/cli.rb', line 11

def self.execute!
  new.execute!
end

.password_prompt(prompt = "Password: ") ⇒ Object

Prompt for a password using echo suppression.



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# File 'lib/switchtower/cli.rb', line 53

def self.password_prompt(prompt="Password: ")
  sync = STDOUT.sync
  begin
    with_echo do
      STDOUT.sync = true
      print(prompt)
      STDIN.gets.chomp
    end
  ensure
    STDOUT.sync = sync
    puts
  end
end

.with_echo ⇒ Object

execute the associated block with echo-suppression enabled. Note that if termios is not available, echo suppression will not be available either.



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# File 'lib/switchtower/cli.rb', line 45

def self.with_echo
  echo(false)
  yield
ensure
  echo(true)
end

Instance Method Details

#execute! ⇒ Object

Beginning running SwitchTower based on the configured options.



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# File 'lib/switchtower/cli.rb', line 215

def execute!
  if !@options[:recipes].empty?
    execute_recipes!
  elsif @options[:apply_to]
    execute_apply_to!
  end
end