Module: Std

Defined in:
lib/vmbuilder_plugins/std.rb

Overview

Purpose

Std is a Capistrano plugin that provides a set of standard methods refactored out of several Capistrano task libraries.

Installs within Capistrano as the plugin std

Usage

require 'vmbuilder_plugins/std'

Prefix all calls to the library with std.

Instance Method Summary collapse

Instance Method Details

#connect_as_root(&block) ⇒ Object

Wrap this around your task to force a connection as root. Flushes the session cache before and after the connection.

std.connect_as_root do
  install_sudo
end



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# File 'lib/vmbuilder_plugins/std.rb', line 120

def connect_as_root (&block)
  begin
    tempuser = user
    set :user, "root"
    actor.sessions.delete_if { true }
    yield tempuser
  ensure
    set :user, tempuser if tempuser
    actor.sessions.delete_if { true }
  end
end

#fput(file_pattern, destination, options = {}) ⇒ Object

Copies the files specified by file_pattern to destination

Error checking is minimal - a pattern onto a single file will result in destination containing the data from the last file only.

Installs via sudo, options are as for put.



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# File 'lib/vmbuilder_plugins/std.rb', line 40

def fput(file_pattern, destination, options={})
  logger.info file_pattern
  Dir.glob(file_pattern) do |fname|
    if File.readable?(fname) then
	if MMAP
 logger.debug "Using Memory Mapped File Upload"
 fdata=Mmap.new(fname,"r", Mmap::MAP_SHARED, :advice => Mmap::MADV_SEQUENTIAL)
      else
 fdata=File.open(fname).read
	end
	su_put(fdata, destination, File.join('/tmp',File.basename(fname)), options)
    else
	logger.error "Unable to read file #{fname}"
    end
  end
end

#ignore_no_servers_error(&block) ⇒ Object

Wrap this around your task calls to catch the no servers error and ignore it

std.ignore_no_servers_error do
  activate_mysql
end



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# File 'lib/vmbuilder_plugins/std.rb', line 101

def ignore_no_servers_error (&block)
  begin
    yield
  rescue RuntimeError => failure
    if failure.message =~ /no servers matched/
	logger.debug "Ignoring 'no servers matched' error in task #{current_task.name}"
    else
	raise
    end
  end
end

#patch(patchfile, level = '0', where = '/') ⇒ Object

Run a patchfile on the servers Ignores reverses and rejects.



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# File 'lib/vmbuilder_plugins/std.rb', line 164

def patch(patchfile, level = '0', where = '/')
  temp_name = random_string
  begin
    fput(patchfile, temp_name, :mode => 0600)
    send(run_method, %{
      patch -p#{level} -tNd #{where} -r /dev/null < #{temp_name} || true
    })
  ensure
    delete temp_name
  end
end

#put_template(template, destination, options = {}) ⇒ Object

Render a template file and upload it to the servers



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# File 'lib/vmbuilder_plugins/std.rb', line 189

def put_template(template, destination, options={})
  if MMAP
    logger.debug "Using Memory Mapped File Upload"
    fdata=Mmap.new(template,"r", Mmap::MAP_SHARED, :advice => Mmap::MADV_SEQUENTIAL)
  else
    fdata=File.read(template)
  end
  put(render(:template => fdata), destination, options)
end

#random_string(size = 10) ⇒ Object

Returns a random string of alphanumeric characters of size size Useful for passwords, usernames and the like.



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# File 'lib/vmbuilder_plugins/std.rb', line 134

def random_string(size=10)
  s = ""
  size.times { s << (i = rand(62); i += ((i < 10) ? 48 : ((i < 36) ? 55 : 61 ))).chr }
  s
end

#relative_path(from_str, to_str) ⇒ Object

Return a relative path from the destination directory from_str to the target file/directory to_str. Used to create relative symbolic link paths.



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# File 'lib/vmbuilder_plugins/std.rb', line 144

def relative_path (from_str, to_str) 
  require 'pathname'
  Pathname.new(to_str).relative_path_from(Pathname.new(from_str)).to_s
end

#ruby(cmd, options = {}, &block) ⇒ Object

Run a ruby command file on the servers



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# File 'lib/vmbuilder_plugins/std.rb', line 151

def ruby(cmd, options={}, &block)
  temp_name = random_string + ".rb"
  begin
    put(cmd, temp_name, :mode => 0700)
    send(run_method, "ruby #{temp_name}", options, &block)
  ensure
    delete temp_name
  end
end

#su_delete(path, options = {}) ⇒ Object

Deletes the given file(s) from all servers targetted by the current task, but runs the delete command according to the current setting of :use_sudo.

If :recursive => true is specified, it may be used to remove directories.



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# File 'lib/vmbuilder_plugins/std.rb', line 182

def su_delete(path, options={})
  cmd = "rm -%sf #{path}" % (options[:recursive] ? "r" : "")
  send(run_method, cmd, options)
end

#su_put(data, destination, temporary_area = '/tmp', options = {}) ⇒ Object

Upload data to temporary_area before installing it in destination using sudo.

options are as for put



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# File 'lib/vmbuilder_plugins/std.rb', line 62

def su_put(data, destination, temporary_area='/tmp', options={})
  temporary_area = File.join(temporary_area,"#{File.basename(destination)}-$CAPISTRANO:HOST$") 
  put(data, temporary_area, options)
  send run_method, <<-CMD
    sh -c "install -m#{sprintf("%3o",options[:mode]||0755)} #{temporary_area} #{destination} &&
    rm -f #{temporary_area}"
  CMD
end

#unzip(file_pattern, destination, options = {}) ⇒ Object

Copies the file_pattern, which is assumed to be a tar file of some description (gzipped or plain), and unpacks it into destination.



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# File 'lib/vmbuilder_plugins/std.rb', line 74

def unzip(file_pattern, destination, options={})
  Dir.glob(file_pattern) do |fname|
    if File.readable?(fname) then
	target="/tmp/#{File.basename(fname)}"
	if MMAP
 logger.debug "Using Memory Mapped File Upload"
 fdata=Mmap.new(fname,"r", Mmap::MAP_SHARED, :advice => Mmap::MADV_SEQUENTIAL)
      else
 fdata=File.open(fname).read
	end
	put(fdata, target, options)
	send run_method, <<-CMD
 sh -c "cd #{destination} &&
 zcat -f #{target} | tar xvf - &&
 rm -f #{target}"
	CMD
    end
  end
end