Class: Rake::RemoteTask

Inherits:
Task
  • Object
show all
Includes:
Open4
Defined in:
lib/rake_remote_task.rb

Overview

Rake::RemoteTask is a subclass of Rake::Task that adds remote_actions that execute in parallel on multiple hosts via ssh.

Defined Under Namespace

Classes: Action

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Task

#vlad_original_execute

Constructor Details

#initialize(task_name, app) ⇒ RemoteTask

Create a new task named task_name attached to Rake::Application app.



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# File 'lib/rake_remote_task.rb', line 136

def initialize(task_name, app)
  super
  @remote_actions = []
end

Instance Attribute Details

#options ⇒ Object

Options for execution of this task.



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# File 'lib/rake_remote_task.rb', line 120

def options
  @options
end

#remote_actions ⇒ Object (readonly)

An Array of Actions this host will perform during execution. Use enhance to add new actions to a task.



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# File 'lib/rake_remote_task.rb', line 131

def remote_actions
  @remote_actions
end

#target_host ⇒ Object

The host this task is running on during execution.



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# File 'lib/rake_remote_task.rb', line 125

def target_host
  @target_host
end

Class Method Details

.all_hosts ⇒ Object

Returns an Array with every host configured.



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# File 'lib/rake_remote_task.rb', line 245

def self.all_hosts
  hosts_for(roles.keys)
end

.default_env ⇒ Object

The default environment values. Used for resetting (mostly for tests).



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# File 'lib/rake_remote_task.rb', line 253

def self.default_env
  @@default_env
end

.env ⇒ Object

The vlad environment.



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# File 'lib/rake_remote_task.rb', line 260

def self.env
  @@env
end

.fetch(name, default = nil) ⇒ Object

Fetches environment variable name from the environment using default default.



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# File 'lib/rake_remote_task.rb', line 268

def self.fetch name, default = nil
  name = name.to_s if Symbol === name
  if @@env.has_key? name then
    protect_env(name) do
      v = @@env[name]
      v = @@env[name] = v.call if Proc === v
      v
    end
  elsif default
    v = @@env[name] = default
  else
    raise Vlad::FetchError
  end
end

.host(host_name, *roles) ⇒ Object

Add host host_name that belongs to roles. Extra arguments may be specified for the host as a hash as the last argument.

host is the inversion of role:

host 'db1.example.com', :db, :master_db

Is equivalent to:

role :db, 'db1.example.com'
role :master_db, 'db1.example.com'



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# File 'lib/rake_remote_task.rb', line 296

def self.host host_name, *roles
  opts = Hash === roles.last ? roles.pop : {}

  roles.each do |role_name|
    role role_name, host_name, opts.dup
  end
end

.hosts_for(*roles) ⇒ Object

Returns an Array of all hosts in roles.



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# File 'lib/rake_remote_task.rb', line 307

def self.hosts_for *roles
  roles.flatten.map { |r|
    self.roles[r].keys
  }.flatten.uniq.sort
end

.mandatory(name, desc) ⇒ Object

:nodoc:



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# File 'lib/rake_remote_task.rb', line 313

def self.mandatory name, desc # :nodoc:
  self.set(name) do
    raise(Vlad::ConfigurationError,
          "Please specify the #{desc} via the #{name.inspect} variable")
  end
end

.protect_env(name) ⇒ Object

Ensures exclusive access to name.



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# File 'lib/rake_remote_task.rb', line 323

def self.protect_env name # :nodoc:
  @@env_locks[name].synchronize do
    yield
  end
end

.remote_task(name, options = {}, &block) ⇒ Object

Adds a remote task named name with options options that will execute block.



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# File 'lib/rake_remote_task.rb', line 333

def self.remote_task name, options = {}, &block
  t = Rake::RemoteTask.define_task(name, &block)
  t.options = options
  t
end

.reserved_name?(name) ⇒ Boolean

Ensures name does not conflict with an existing method.

Returns:

  • (Boolean) 


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# File 'lib/rake_remote_task.rb', line 342

def self.reserved_name? name # :nodoc:
  !@@env.has_key?(name.to_s) && self.respond_to?(name)
end

.reset ⇒ Object

Resets vlad, restoring all roles, tasks and environment variables to the defaults.



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# File 'lib/rake_remote_task.rb', line 350

def self.reset
  @@roles = Hash.new { |h,k| h[k] = {} }
  @@env = {}
  @@tasks = {}
  @@env_locks = Hash.new { |h,k| h[k] = Mutex.new }

  @@default_env.each do |k,v|
    case v
    when Symbol, Fixnum, nil, true, false, 42 then # ummmm... yeah. bite me.
      @@env[k] = v
    else
      @@env[k] = v.dup
    end
  end
end

.role(role_name, host, args = {}) ⇒ Object

Adds role role_name with host and args for that host.

Raises:

  • (ArgumentError) 


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# File 'lib/rake_remote_task.rb', line 369

def self.role role_name, host, args = {}
  raise ArgumentError, "invalid host" if host.nil? or host.empty?
  @@roles[role_name][host] = args
end

.roles ⇒ Object

The configured roles.



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# File 'lib/rake_remote_task.rb', line 377

def self.roles
  host domain, :app, :web, :db if @@roles.empty?

  @@roles
end

.set(name, value = nil, &default_block) ⇒ Object

Set environment variable name to value or default_block.

If default_block is defined, the block will be executed the first time the variable is fetched, and the value will be used for every subsequent fetch.

Raises:

  • (ArgumentError) 


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# File 'lib/rake_remote_task.rb', line 390

def self.set name, value = nil, &default_block
  raise ArgumentError, "cannot provide both a value and a block" if
    value and default_block
  raise ArgumentError, "cannot set reserved name: '#{name}'" if
    Rake::RemoteTask.reserved_name?(name) unless $TESTING

  Rake::RemoteTask.default_env[name.to_s] = Rake::RemoteTask.env[name.to_s] =
    value || default_block

  Object.send :define_method, name do
    Rake::RemoteTask.fetch name
  end
end

.set_defaults ⇒ Object

Sets all the default values. Should only be called once. Use reset if you need to restore values.



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# File 'lib/rake_remote_task.rb', line 408

def self.set_defaults
  @@default_env ||= {}
  self.reset

  mandatory :code_repo,  "code repo path"
  mandatory :deploy_to,  "deploy path"
  mandatory :domain,     "server domain"

  simple_set(:deploy_timestamped, true,
             :deploy_via,         :export,
             :keep_releases,      5,
             :migrate_args,       "",
             :migrate_target,     :latest,
             :rails_env,          "production",
             :rake_cmd,           "rake",
             :revision,           "head",
             :rsync_cmd,          "rsync",
             :rsync_flags,        ['-azP', '--delete'],
             :ssh_cmd,            "ssh",
             :ssh_flags,          nil,
             :sudo_cmd,           "sudo",
             :sudo_flags,         nil)

  set(:current_release)    { File.join(releases_path, releases[-1]) }
  set(:latest_release)     { deploy_timestamped ?release_path: current_release }
  set(:previous_release)   { File.join(releases_path, releases[-2]) }
  set(:release_name)       { Time.now.utc.strftime("%Y%m%d%H%M%S") }
  set(:release_path)       { File.join(releases_path, release_name) }
  set(:releases)           { task.run("ls -x #{releases_path}").split.sort }

  set_path :current_path,  "current"
  set_path :releases_path, "releases"
  set_path :scm_path,      "scm"
  set_path :shared_path,   "shared"

  set(:sudo_password) do
    state = `stty -g`

    raise Vlad::Error, "stty(1) not found" unless $?.success?

    begin
      system "stty -echo"
      $stdout.print "sudo password: "
      $stdout.flush
      sudo_password = $stdin.gets
      $stdout.puts
    ensure
      system "stty #{state}"
    end
    sudo_password
  end
end

.set_path(name, subdir) ⇒ Object

:nodoc:



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# File 'lib/rake_remote_task.rb', line 461

def self.set_path(name, subdir) # :nodoc:
  set(name) { File.join(deploy_to, subdir) }
end

.simple_set(*args) ⇒ Object

:nodoc:



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# File 'lib/rake_remote_task.rb', line 465

def self.simple_set(*args) # :nodoc:
  args = Hash[*args]
  args.each do |k, v|
    set k, v
  end
end

.task ⇒ Object

The Rake::RemoteTask executing in this Thread.



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# File 'lib/rake_remote_task.rb', line 475

def self.task
  Thread.current[:task]
end

.tasks ⇒ Object

The configured Rake::RemoteTasks.



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# File 'lib/rake_remote_task.rb', line 482

def self.tasks
  @@tasks
end

Instance Method Details

#enhance(deps = nil, &block) ⇒ Object

Add remote action block to this task with dependencies deps. See Rake::Task#enhance.



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# File 'lib/rake_remote_task.rb', line 150

def enhance(deps=nil, &block)
  original_enhance(deps) # can't use super because block passed regardless.
  @remote_actions << Action.new(self, block) if block_given?
  self
end

#execute(args = nil) ⇒ Object

Execute this action. Local actions will be performed first, then remote actions will be performed in parallel on each host configured for this RemoteTask.

Raises:



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# File 'lib/rake_remote_task.rb', line 161

def execute(args = nil)
  raise(Vlad::ConfigurationError,
        "No target hosts specified for task: #{self.name}") if
    target_hosts.empty?

  super args

  @remote_actions.each { |act| act.execute(target_hosts, args) }
end

#original_enhance ⇒ Object

Add a local action to this task. This calls Rake::Task#enhance.



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# File 'lib/rake_remote_task.rb', line 144

alias_method :original_enhance, :enhance

#rsync(local, remote) ⇒ Object

Use rsync to send local to remote on target_host.



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# File 'lib/rake_remote_task.rb', line 174

def rsync local, remote
  cmd = [rsync_cmd, rsync_flags, local, "#{@target_host}:#{remote}"].flatten.compact

  success = system(*cmd)

  unless success then
    raise Vlad::CommandFailedError, "execution failed: #{cmd.join ' '}"
  end
end

#run(command) ⇒ Object

Use ssh to execute command on target_host. If command uses sudo, the sudo password will be prompted for then saved for subsequent sudo commands.



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# File 'lib/rake_remote_task.rb', line 188

def run command
  cmd = [ssh_cmd, ssh_flags, target_host, command].compact
  result = []

  warn cmd.join(' ') if $TRACE

  pid, inn, out, err = popen4(*cmd)

  inn.sync   = true
  streams    = [out, err]
  out_stream = {
    out => $stdout,
    err => $stderr,
  }

  # Handle process termination ourselves
  status = nil
  Thread.start do
    status = Process.waitpid2(pid).last
  end

  until streams.empty? do
    # don't busy loop
    selected, = select streams, nil, nil, 0.1

    next if selected.nil? or selected.empty?

    selected.each do |stream|
      if stream.eof? then
        streams.delete stream if status # we've quit, so no more writing
        next
      end

      data = stream.readpartial(1024)
      out_stream[stream].write data

      if stream == err and data =~ /^Password:/ then
        inn.puts sudo_password
        data << "\n"
        $stderr.write "\n"
      end

      result << data
    end
  end

  unless status.success? then
    raise(Vlad::CommandFailedError,
          "execution failed with status #{status.exitstatus}: #{cmd.join ' '}")
  end

  result.join
end

#sudo(command) ⇒ Object

Execute command under sudo using run.



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# File 'lib/rake_remote_task.rb', line 489

def sudo command
  run [sudo_cmd, sudo_flags, command].compact.join(" ")
end

#target_hosts ⇒ Object

The hosts this task will execute on. The hosts are determined from the role this task belongs to.

The target hosts may be overridden by providing a comma-separated list of commands to the HOSTS environment variable:

rake my_task HOSTS=app1.example.com,app2.example.com



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# File 'lib/rake_remote_task.rb', line 502

def target_hosts
  if hosts = ENV["HOSTS"] then
    hosts.strip.gsub(/\s+/, '').split(",")
  else
    roles = options[:roles]
    roles ? Rake::RemoteTask.hosts_for(roles) : Rake::RemoteTask.all_hosts
  end
end