Class: Mixlib::ShellOut

Inherits:
Object
  • Object
show all
Includes:
Unix, Windows
Defined in:
lib/mixlib/shellout.rb,
lib/mixlib/shellout/unix.rb,
lib/mixlib/shellout/version.rb,
lib/mixlib/shellout/windows.rb,
lib/mixlib/shellout/exceptions.rb

Defined Under Namespace

Modules: Unix, Windows Classes: CommandTimeout, InvalidCommandOption, ShellCommandFailed

Constant Summary collapse

READ_WAIT_TIME = 
0.01
READ_SIZE = 
4096
DEFAULT_READ_TIMEOUT = 
600
VERSION = 
"2.0.1"

Constants included from Unix

Unix::ONE_DOT_EIGHT_DOT_SEVEN

Constants included from Windows

Windows::TIME_SLICE

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*command_args) ⇒ ShellOut

Arguments:

Takes a single command, or a list of command fragments. These are used as arguments to Kernel.exec. See the Kernel.exec documentation for more explanation of how arguments are evaluated. The last argument can be an options Hash.

Options:

If the last argument is a Hash, it is removed from the list of args passed to exec and used as an options hash. The following options are available:

  • user: the user the commmand should run as. if an integer is given, it is used as a uid. A string is treated as a username and resolved to a uid with Etc.getpwnam

  • group: the group the command should run as. works similarly to user

  • cwd: the directory to chdir to before running the command

  • umask: a umask to set before running the command. If given as an Integer, be sure to use two leading zeros so it’s parsed as Octal. A string will be treated as an octal integer

  • returns: one or more Integer values to use as valid exit codes for the subprocess. This only has an effect if you call error! after run_command.

  • environment: a Hash of environment variables to set before the command is run.

  • timeout: a Numeric value for the number of seconds to wait on the child process before raising an Exception. This is calculated as the total amount of time that ShellOut waited on the child process without receiving any output (i.e., IO.select returned nil). Default is 60 seconds. Note: the stdlib Timeout library is not used.

  • input: A String of data to be passed to the subcommand. This is written to the child process’ stdin stream before the process is launched. The child’s stdin stream will be a pipe, so the size of input data should not exceed the system’s default pipe capacity (4096 bytes is a safe value, though on newer Linux systems the capacity is 64k by default).

  • live_stream: An IO or Logger-like object (must respond to the append operator <<) that will receive data as ShellOut reads it from the child process. Generally this is used to copy data from the child to the parent’s stdout so that users may observe the progress of long-running commands.

Examples:

Invoke find(1) to search for .rb files:

find = Mixlib::ShellOut.new("find . -name '*.rb'")
find.run_command
# If all went well, the results are on +stdout+
puts find.stdout
# find(1) prints diagnostic info to STDERR:
puts "error messages" + find.stderr
# Raise an exception if it didn't exit with 0
find.error!

Run a command as the www user with no extra ENV settings from /tmp

cmd = Mixlib::ShellOut.new("apachectl", "start", :user => 'www', :env => nil, :cwd => '/tmp')
cmd.run_command # etc.



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# File 'lib/mixlib/shellout.rb', line 157

def initialize(*command_args)
  @stdout, @stderr, @process_status = '', '', ''
  @live_stdout = @live_stderr = nil
  @input = nil
  @log_level = :debug
  @log_tag = nil
  @environment = {}
  @cwd = nil
  @valid_exit_codes = [0]
  @terminate_reason = nil

  if command_args.last.is_a?(Hash)
    parse_options(command_args.pop)
  end

  @command = command_args.size == 1 ? command_args.first : command_args
end

Instance Attribute Details

#command ⇒ Object (readonly)

The command to be executed.



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# File 'lib/mixlib/shellout.rb', line 79

def command
  @command
end

#cwd ⇒ Object

Working directory for the subprocess. Normally set via options to new



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# File 'lib/mixlib/shellout.rb', line 49

def cwd
  @cwd
end

#domain ⇒ Object

Returns the value of attribute domain.



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# File 'lib/mixlib/shellout.rb', line 41

def domain
  @domain
end

#environment ⇒ Object

Environment variables that will be set for the subcommand. Refer to the documentation of new to understand how ShellOut interprets this.



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# File 'lib/mixlib/shellout.rb', line 86

def environment
  @environment
end

#execution_time ⇒ Object (readonly)

The amount of time the subcommand took to execute



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# File 'lib/mixlib/shellout.rb', line 93

def execution_time
  @execution_time
end

#group ⇒ Object

Group the command will run as. Normally set via options passed to new



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# File 'lib/mixlib/shellout.rb', line 46

def group
  @group
end

#input ⇒ Object

ShellOut will push data from :input down the stdin of the subprocss. Normally set via options passed to new. Default: nil



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# File 'lib/mixlib/shellout.rb', line 66

def input
  @input
end

#live_stderr ⇒ Object

When live_stderr is set, the stderr of the subprocess will be copied to it as the subprocess is running.



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# File 'lib/mixlib/shellout.rb', line 61

def live_stderr
  @live_stderr
end

#live_stdout ⇒ Object

When live_stdout is set, the stdout of the subprocess will be copied to it as the subprocess is running.



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# File 'lib/mixlib/shellout.rb', line 57

def live_stdout
  @live_stdout
end

#log_level ⇒ Object

The log level at which ShellOut should log.



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# File 'lib/mixlib/shellout.rb', line 73

def log_level
  @log_level
end

#log_tag ⇒ Object

A string which will be prepended to the log message.



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# File 'lib/mixlib/shellout.rb', line 76

def log_tag
  @log_tag
end

#logger ⇒ Object

If a logger is set, ShellOut will log a message before it executes the command.



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# File 'lib/mixlib/shellout.rb', line 70

def logger
  @logger
end

#password ⇒ Object

Returns the value of attribute password.



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# File 'lib/mixlib/shellout.rb', line 42

def password
  @password
end

#process_status_pipe ⇒ Object (readonly)

Returns the value of attribute process_status_pipe.



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# File 'lib/mixlib/shellout.rb', line 105

def process_status_pipe
  @process_status_pipe
end

#status ⇒ Object (readonly)

A Process::Status (or ducktype) object collected when the subprocess is reaped.



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# File 'lib/mixlib/shellout.rb', line 103

def status
  @status
end

#stderr ⇒ Object (readonly)

Data written to stderr by the subprocess



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# File 'lib/mixlib/shellout.rb', line 99

def stderr
  @stderr
end

#stderr_pipe ⇒ Object (readonly)

Returns the value of attribute stderr_pipe.



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# File 'lib/mixlib/shellout.rb', line 105

def stderr_pipe
  @stderr_pipe
end

#stdin_pipe ⇒ Object (readonly)

Returns the value of attribute stdin_pipe.



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# File 'lib/mixlib/shellout.rb', line 105

def stdin_pipe
  @stdin_pipe
end

#stdout ⇒ Object (readonly)

Data written to stdout by the subprocess



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# File 'lib/mixlib/shellout.rb', line 96

def stdout
  @stdout
end

#stdout_pipe ⇒ Object (readonly)

Returns the value of attribute stdout_pipe.



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# File 'lib/mixlib/shellout.rb', line 105

def stdout_pipe
  @stdout_pipe
end

#timeout ⇒ Object 



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# File 'lib/mixlib/shellout.rb', line 207

def timeout
  @timeout || DEFAULT_READ_TIMEOUT
end

#umask ⇒ Object

The umask that will be set for the subcommand.



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# File 'lib/mixlib/shellout.rb', line 82

def umask
  @umask
end

#user ⇒ Object

User the command will run as. Normally set via options passed to new



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# File 'lib/mixlib/shellout.rb', line 40

def user
  @user
end

#valid_exit_codes ⇒ Object

An Array of acceptable exit codes. #error? (and #error!) use this list to determine if the command was successful. Normally set via options to new



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# File 'lib/mixlib/shellout.rb', line 53

def valid_exit_codes
  @valid_exit_codes
end

#with_logon ⇒ Object

Returns the value of attribute with_logon.



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# File 'lib/mixlib/shellout.rb', line 43

def with_logon
  @with_logon
end

Instance Method Details

#error! ⇒ Object

If #error? is true, calls invalid!, which raises an Exception.

Returns

nil:

always returns nil when it does not raise

Raises

::ShellCommandFailed:

via invalid!



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# File 'lib/mixlib/shellout.rb', line 264

def error!
  invalid!("Expected process to exit with #{valid_exit_codes.inspect}, but received '#{exitstatus}'") if error?
end

#error? ⇒ Boolean

Checks the exitstatus against the set of valid_exit_codes.

Returns

true if exitstatus is not in the list of valid_exit_codes, false otherwise.

Returns:

  • (Boolean) 


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# File 'lib/mixlib/shellout.rb', line 255

def error?
  !Array(valid_exit_codes).include?(exitstatus)
end

#exitstatus ⇒ Object

The exit status of the subprocess. Will be nil if the command is still running or died without setting an exit status (e.g., terminated by ‘kill -9`).



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# File 'lib/mixlib/shellout.rb', line 228

def exitstatus
  @status && @status.exitstatus
end

#format_for_exception ⇒ Object

Creates a String showing the output of the command, including a banner showing the exact command executed. Used by invalid! to show command results when the command exited with an unexpected status.



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# File 'lib/mixlib/shellout.rb', line 214

def format_for_exception
  msg = ""
  msg << "#{@terminate_reason}\n" if @terminate_reason
  msg << "---- Begin output of #{command} ----\n"
  msg << "STDOUT: #{stdout.strip}\n"
  msg << "STDERR: #{stderr.strip}\n"
  msg << "---- End output of #{command} ----\n"
  msg << "Ran #{command} returned #{status.exitstatus}" if status
  msg
end

#gid ⇒ Object

The gid that the subprocess will switch to. If the group attribute is given as a group name, it is converted to a gid by Etc.getgrnam



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# File 'lib/mixlib/shellout.rb', line 202

def gid
  return nil unless group
  group.kind_of?(Integer) ? group : Etc.getgrnam(group.to_s).gid
end

#inspect ⇒ Object 



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# File 'lib/mixlib/shellout.rb', line 281

def inspect
  "<#{self.class.name}##{object_id}: command: '#@command' process_status: #{@status.inspect} " +
  "stdout: '#{stdout.strip}' stderr: '#{stderr.strip}' child_pid: #{@child_pid.inspect} " +
  "environment: #{@environment.inspect} timeout: #{timeout} user: #@user group: #@group working_dir: #@cwd >"
end

#invalid!(msg = nil) ⇒ Object

Raises a ShellCommandFailed exception, appending the command’s stdout, stderr, and exitstatus to the exception message.

Arguments

msg: A String to use as the basis of the exception message. The default explanation is very generic, providing a more informative message is highly encouraged.

Raises

ShellCommandFailed always

Raises:



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# File 'lib/mixlib/shellout.rb', line 276

def invalid!(msg=nil)
  msg ||= "Command produced unexpected results"
  raise ShellCommandFailed, msg + "\n" + format_for_exception
end

#live_stream ⇒ Object

Returns the stream that both is being used by both live_stdout and live_stderr, or nil



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# File 'lib/mixlib/shellout.rb', line 176

def live_stream
  live_stdout == live_stderr ? live_stdout : nil
end

#live_stream=(stream) ⇒ Object

A shortcut for setting both live_stdout and live_stderr, so that both the stdout and stderr from the subprocess will be copied to the same stream as the subprocess is running.



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# File 'lib/mixlib/shellout.rb', line 183

def live_stream=(stream)
  @live_stdout = @live_stderr = stream
end

#run_command ⇒ Object

Run the command, writing the command’s standard out and standard error to stdout and stderr, and saving its exit status object to status

Returns

returns self; stdout, stderr, status, and exitstatus will be populated with results of the command

Raises

  • Errno::EACCES when you are not privileged to execute the command

  • Errno::ENOENT when the command is not available on the system (or not in the current $PATH)

  • CommandTimeout when the command does not complete within timeout seconds (default: 600s)



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# File 'lib/mixlib/shellout.rb', line 243

def run_command
  if logger
    log_message = (log_tag.nil? ? "" : "#@log_tag ") << "sh(#@command)"
    logger.send(log_level, log_message)
  end
  super
end

#uid ⇒ Object

The uid that the subprocess will switch to. If the user attribute was given as a username, it is converted to a uid by Etc.getpwnam



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# File 'lib/mixlib/shellout.rb', line 195

def uid
  return nil unless user
  user.kind_of?(Integer) ? user : Etc.getpwnam(user.to_s).uid
end