Module: Backup::CLI::Helpers

Included in:
Archive, Backup::Checksum::Base, Backup::Compressor::Base, Database::Base, Encryptor::Base, Model, Packager, Pipeline, Splitter, Storage::RSync, Syncer::Base
Defined in:
lib/backup/cli/helpers.rb

Constant Summary collapse

UTILITY = 
{}

Instance Method Summary collapse

Instance Method Details

#command_name(command) ⇒ Object

Returns the name of the command name from the given command line



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# File 'lib/backup/cli/helpers.rb', line 55

def command_name(command)
  i = command =~ /\s/
  command = command.slice(0, i) if i
  command.split('/')[-1]
end

#raise_if_command_failed!(utility, process_data) ⇒ Object

Inspects the exit code returned from the POpen4 child process. If the exit code isn’t listed in the process_data array, an exception will be raised, aborting the backup process.

Information regarding the error ( EXIT CODE and STDERR ) will be returned to the shell so the user can investigate the issue.

raises Backup::Errors::CLI::SystemCallError



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# File 'lib/backup/cli/helpers.rb', line 69

def raise_if_command_failed!(utility, process_data)
  unless process_data[:ignore_exit_codes].include?(process_data[:status].to_i)

    stderr = process_data[:stderr].empty? ?
        nil : "STDERR:\n#{process_data[:stderr]}\n"
    stdout = process_data[:stdout].empty? ?
        nil : "STDOUT:\n#{process_data[:stdout]}\n"

    raise Errors::CLI::SystemCallError, <<-EOS
      Failed to run #{utility} on #{RUBY_PLATFORM}
      The following information should help to determine the problem:
      Exit Code: #{process_data[:status]}
      #{stderr}#{stdout}
    EOS
  end
end

#run(command, options = {}) ⇒ Object

Runs a given command in an isolated (sub) process using POpen4. The STDOUT, STDERR and the returned exit code of the utility will be stored in the process_data Hash.

If a command returns an exit code other than 0, an exception will raise and the backup process will abort. Some utilities return exit codes other than 0 which aren’t an issue in Backup’s context. If this is the case, you can pass in an array of exit codes to ignore (whitelist), for example:

run("tar -cf /output.tar /some/folder", :ignore_exit_codes => [1])

So if the ‘tar` utility returns in this case 1, Backup will consider it an acceptable return code.

Note: Exit code 0 is always automatically added to the :ignore_exit_codes array, regardless of whether you specify an

array to ignore or not.



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# File 'lib/backup/cli/helpers.rb', line 22

def run(command, options = {})
  command.gsub!(/^\s+/, "")

  process_data                     = Hash.new
  pid, stdin, stdout, stderr       = Open4::popen4(command)
  ignored, process_data[:status]   = Process::waitpid2(pid)
  process_data[:stdout]            = stdout.read
  process_data[:stderr]            = stderr.read
  process_data[:ignore_exit_codes] = ((options[:ignore_exit_codes] || Array.new) << 0).uniq

  raise_if_command_failed!(command_name(command), process_data)
  process_data[:stdout]
end

#utility(name) ⇒ Object

Returns the full path to the specified utility. Raises an error if utility can not be found in the system’s $PATH



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# File 'lib/backup/cli/helpers.rb', line 39

def utility(name)
  path = UTILITY[name] || %x[which #{name} 2>/dev/null].chomp
  if path.empty?
    raise Errors::CLI::UtilityNotFoundError, <<-EOS
      Path to '#{ name }' could not be found.
      Make sure the specified utility is installed
      and available in your system's $PATH.
      If this is a database utility, you may need to specify the full path
      using the Database's '<utility_name>_utility' configuration setting.
    EOS
  end
  UTILITY[name] = path
end