Module: Command

Defined in:
lib/prick/local/command.rb

Defined Under Namespace

Classes: Error

Class Method Summary collapse

Class Method Details

.command(env = {}, cmd, argv: nil, stdin: nil, stderr: nil, fail: true) ⇒ Object

Execute the shell command ‘cmd’ and return standard-output as an array of strings. If :stdin is a string or an array of lines if will be fed to the command on standard-input, if it is a IO object that IO object is piped to the command

By default #command pass through error message to stderr but if :stderr is true, #command will instead return a tuple of stdout/stderr lines. If :stderr is false, stderr is ignored and is the same as adding “2>/dev/null” to the command

#command raises a Command::Error exception if the command returns with an exit code != 0 unless :fail is false. In that case the the exit code can be fetched from Command::status



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# File 'lib/prick/local/command.rb', line 34

def command(env = {}, cmd, argv: nil, stdin: nil, stderr: nil, fail: true)
  command_wrapper(cmd, stdin: stdin, stderr: stderr, fail: fail) {
    # Add standard shell options
    bashcmd = "set -o errexit\nset -o pipefail\n#{cmd}"

    # Add arguments if present
    bashcmd = [bashcmd, *argv].join(' ') if argv

    # Clean bundler environment so that prick can be run in development mode.
    # The problem is that the bundler environment is inherited by
    # subprocesses and interferes with loading ruby commands. FIXME This is
    # only relevant when running prick in development mode
    ENV.delete_if { |k,v| %w(RUBYOPT RUBYLIB _).include?(k) || k =~ /^BUNDLER?_/ }

    # Setup environment
    env = env.map { |k,v| [k.to_s, v.to_s] }.to_h # Convert array values to strings
    env.each { |k,v| ENV[k] = v }

    Kernel.exec(env, bashcmd)
  }
end

.command?(env = {}, cmd, expect: 0, argv: nil, stdin: nil, stderr: false) ⇒ Boolean

Like command but returns true if the command exited with the expected status. Note that it suppresses standard-error by default

Returns:

  • (Boolean) 


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# File 'lib/prick/local/command.rb', line 59

def command?(env = {}, cmd, expect: 0, argv: nil, stdin: nil, stderr: false)
  command(env, cmd, argv: argv, stdin: stdin, stderr: stderr, fail: false)
  @status == expect
end

.command_wrapper(cmd, stdin: nil, stderr: nil, fail: true, &block) ⇒ Object

cmd is the of the command/script and is only used in error messages



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# File 'lib/prick/local/command.rb', line 98

def command_wrapper(cmd, stdin: nil, stderr: nil, fail: true, &block)
  pw = IO::pipe # pipe[0] for read, pipe[1] for write
  pr = IO::pipe
  pe = IO::pipe

  STDOUT.flush

  pid = fork {
    pw[1].close
    pr[0].close
    pe[0].close

    STDIN.reopen(pw[0])
    pw[0].close

    STDOUT.reopen(pr[1])
    pr[1].close

    STDERR.reopen(pe[1])
    pe[1].close

    yield
  }

  pw[0].close
  pr[1].close
  pe[1].close

  if stdin
    case stdin
      when IO; pw[1].write(stdin.read)
      when String; pw[1].write(stdin)
      when Array; pw[1].write(stdin.join("\n") + "\n")
    end
    pw[1].flush
  end
  pw[1].close # Closing standard input so the command doesn't hang on read

  @status = Process.waitpid2(pid)[1].exitstatus

  out = pr[0].readlines.map(&:chomp)
  err = pe[0].readlines.map(&:chomp)

  pr[0].close
  pe[0].close

  if @status != 0
    @exception = Command::Error.new(cmd, @status, stdin, out, err)
    raise @exception if fail
  else
    @exception = nil
  end

  case stderr
    when true; [out, err]
    when false; out
    when nil
      $stderr.puts err
      out
  end
end

.exception ⇒ Object

Exception of the last command if it failed, otherwise nil TODO What is this used for?



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# File 'lib/prick/local/command.rb', line 68

def exception() @exception end

.script(env = {}, script, argv: nil, stdin: nil, stderr: nil, fail: true) ⇒ Object

Like #command but “execute” the ruby file by requiring it. This is only possible using ruby scripts



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# File 'lib/prick/local/command.rb', line 72

def script(env = {}, script, argv: nil, stdin: nil, stderr: nil, fail: true)

  # Turn script into absolute path or a path relative to the current
  # directory
  if !script.start_with?("/") && !script.start_with?(".")
    script = "./#{script}"
  end

  command_wrapper(script, stdin: stdin, stderr: stderr, fail: fail) {
    ENV.delete_if { |k,v| %w(RUBYOPT RUBYLIB _).include?(k) || k =~ /^BUNDLER?_/ }

    # Setup environment
    env = env.map { |k,v| [k.to_s, v.to_s] }.to_h # Convert array values to strings
    env.each { |k,v| ENV[k] = v }

    # Setup ARGV. Only relevant when running ruby scripts using the 'require'
    # mechanish instead of calling them through the shell
    ARGV.replace (argv || [])

    # 'Execute' script by requiring it
    require script
  }
end

.status ⇒ Object

Exit status of the last command



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# File 'lib/prick/local/command.rb', line 65

def status() @status end