module Chef::Mixin::Command

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NOTE:
The popen4 method upon which all the code here is based has a race
condition where it may fail to read all of the data written to stdout and
stderr after the child process exits. The tests for the code here
occasionally fail because of this race condition, so they have been
tagged "volatile".

This code is considered deprecated, so it should not need to be modified
frequently, if at all. HOWEVER, if you do modify the code here, you must
explicitly enable volatile tests:

  bundle exec rspec spec/unit/mixin/command_spec.rb -t volatile

In addition, you should make a note that tests need to be run with
volatile tests enabled on any pull request or bug report you submit with
your patch.

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Public Instance Methods

chdir_or_tmpdir(dir, &block) click to toggle source

module_function :popen4

# File lib/chef/mixin/command.rb, line 180
def chdir_or_tmpdir(dir, &block)
  dir ||= Dir.tmpdir
  unless File.directory?(dir)
    raise Chef::Exceptions::Exec, "#{dir} does not exist or is not a directory"
  end
  Dir.chdir(dir) do
    block.call
  end
end
handle_command_failures(status, command_output, opts={}) click to toggle source
# File lib/chef/mixin/command.rb, line 146
def handle_command_failures(status, command_output, opts={})
  return if opts[:ignore_failure]
  opts[:returns] ||= 0
  return if Array(opts[:returns]).include?(status.exitstatus)

  # if the log level is not debug, through output of command when we fail
  output = ""
  if Chef::Log.level == :debug || opts[:output_on_failure]
    output << "\n---- Begin output of #{opts[:command]} ----\n"
    output << command_output.to_s
    output << "\n---- End output of #{opts[:command]} ----\n"
  end
  raise Chef::Exceptions::Exec, "#{opts[:command]} returned #{status.exitstatus}, expected #{opts[:returns]}#{output}"
end
output_of_command(command, args) click to toggle source
# File lib/chef/mixin/command.rb, line 109
def output_of_command(command, args)
  Chef::Log.debug("Executing #{command}")
  stderr_string, stdout_string, status = "", "", nil

  exec_processing_block = lambda do |pid, stdin, stdout, stderr|
    stdout_string, stderr_string = stdout.string.chomp, stderr.string.chomp
  end

  args[:cwd] ||= Dir.tmpdir
  unless ::File.directory?(args[:cwd])
    raise Chef::Exceptions::Exec, "#{args[:cwd]} does not exist or is not a directory"
  end

  Dir.chdir(args[:cwd]) do
    if args[:timeout]
      begin
        Timeout.timeout(args[:timeout]) do
          status = popen4(command, args, &exec_processing_block)
        end
      rescue Timeout::Error => e
        Chef::Log.error("#{command} exceeded timeout #{args[:timeout]}")
        raise(e)
      end
    else
      status = popen4(command, args, &exec_processing_block)
    end

    Chef::Log.debug("---- Begin output of #{command} ----")
    Chef::Log.debug("STDOUT: #{stdout_string}")
    Chef::Log.debug("STDERR: #{stderr_string}")
    Chef::Log.debug("---- End output of #{command} ----")
    Chef::Log.debug("Ran #{command} returned #{status.exitstatus}")
  end

  return status, stdout_string, stderr_string
end
run_command(args={}) click to toggle source

Parameters

args<Hash>: A number of required and optional arguments

command<String>, <Array>: A complete command with options to execute or a command and options as an Array
creates<String>: The absolute path to a file that prevents the command from running if it exists
cwd<String>: Working directory to execute command in, defaults to Dir.tmpdir
timeout<String>: How many seconds to wait for the command to execute before timing out
returns<String>: The single exit value command is expected to return, otherwise causes an exception
ignore_failure<Boolean>: Whether to raise an exception on failure, or just return the status
output_on_failure<Boolean>: Return output in raised exception regardless of Log.level

user<String>: The UID or user name of the user to execute the command as
group<String>: The GID or group name of the group to execute the command as
environment<Hash>: Pairs of environment variable names and their values to set before execution

Returns

Returns the exit status of args

# File lib/chef/mixin/command.rb, line 78
def run_command(args={})
  status, stdout, stderr = run_command_and_return_stdout_stderr(args)

  status
end
run_command_and_return_stdout_stderr(args={}) click to toggle source

works same as above, except that it returns stdout and stderr requirement => platforms like solaris 9,10 has wierd issues where even in command failure the exit code is zero, so we need to lookup stderr.

# File lib/chef/mixin/command.rb, line 87
def run_command_and_return_stdout_stderr(args={})
  command_output = ""

  args[:ignore_failure] ||= false
  args[:output_on_failure] ||= false

  # TODO: This is the wrong place for this responsibility.
  if args.has_key?(:creates)
    if File.exists?(args[:creates])
      Chef::Log.debug("Skipping #{args[:command]} - creates #{args[:creates]} exists.")
      return false
    end
  end

  status, stdout, stderr = output_of_command(args[:command], args)
  command_output << "STDOUT: #{stdout}"
  command_output << "STDERR: #{stderr}"
  handle_command_failures(status, command_output, args)

  return status, stdout, stderr
end
run_command_with_systems_locale(args={}) click to toggle source

Call run_command but set LC_ALL to the system's current environment so it doesn't get changed to C.

Parameters

args<Hash>: A number of required and optional arguments that will be handed out to run_command

Returns

Returns the result of run_command

# File lib/chef/mixin/command.rb, line 168
def run_command_with_systems_locale(args={})
  args[:environment] ||= {}
  args[:environment]["LC_ALL"] = ENV["LC_ALL"]
  run_command args
end