Class: CommonMob::Shell

Inherits:
Object
  • Object
show all
Defined in:
lib/common_mob/shell.rb

Defined Under Namespace

Classes: ShellResult

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*args, &block) ⇒ Shell

Returns a new instance of Shell.



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# File 'lib/common_mob/shell.rb', line 28

def initialize(*args,&block)
  @block = block
  @options = if Hash === args.last then args.pop else {} end

  unless args.empty?
    @options[:cmd] = args
  end

  @options[:stream] = false unless @options.key?(:stream)
end

Instance Attribute Details

#options ⇒ Object (readonly)

Returns the value of attribute options.



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# File 'lib/common_mob/shell.rb', line 26

def options
  @options
end

Instance Method Details

#debug(*msg) ⇒ Object 



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# File 'lib/common_mob/shell.rb', line 22

def debug(*msg)
  AngryMob::Mob.ui.debug "sh: #{msg * ' '}"
end

#execute ⇒ Object 



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# File 'lib/common_mob/shell.rb', line 39

def execute
  error,out = nil,nil

  rv = popen4(options) {|pid,stdin,stdout,stderr|
    out   = stdout.read
    error = stderr.read
  }
  
  # TODO print as debug

  rv.stderr = error
  rv.stdout = out

  rv
end

#massaged_args(args) ⇒ Object 



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# File 'lib/common_mob/shell.rb', line 302

def massaged_args args
  returning(args.dup) do |args_to_print|
    args_to_print[:environment] = e = args[:environment].dup

    %w{LC_ALL GEM_HOME GEM_PATH RUBYOPT BUNDLE_GEMFILE}.each {|env| e.delete(env)}

    args_to_print['cwd'] = args_to_print['cwd'].to_s if args_to_print['cwd']

    args_to_print.delete_if{|k,v| v.blank?}
  end
end

#ok? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/common_mob/shell.rb', line 59

def ok?
  execute.ok?
end

#popen4(args = {}, &b) ⇒ Object

This is taken directly from Chef and then modified to suit the needs of Igor.

This is taken directly from Ara T Howard’s Open4 library, and then modified to suit the needs of Chef. Any bugs here are most likely my own, and not Ara’s.

The original appears in external/open4.rb in its unmodified form.

Thanks Ara!



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# File 'lib/common_mob/shell.rb', line 95

def popen4(args={}, &b)

  cmd = args[:cmd]

 
  # Do we wait for the child process to die before we yield
  # to the block, or after?
  #
  # By default, we are waiting before we yield the block.
  args[:stream] ||= false
  

  args[:user] ||= nil
  unless args[:user].kind_of?(Integer)
    args[:user] = Etc.getpwnam(args[:user]).uid if args[:user]
  end

  args[:group] ||= nil
  unless args[:group].kind_of?(Integer)
    args[:group] = Etc.getgrnam(args[:group]).gid if args[:group]
  end


  args[:environment] ||= {}

  # Default on C locale so parsing commands output can be done
  # independently of the node's default locale.
  # "LC_ALL" could be set to nil, in which case we also must ignore it.
  unless args[:environment].has_key?("LC_ALL")
    args[:environment]["LC_ALL"] = "C"
  end

  unless TrueClass === args[:without_cleaning_bundler]
    args[:environment].update('RUBYOPT' => nil, 'BUNDLE_GEMFILE' => nil, 'GEM_HOME' => nil, 'GEM_PATH' => nil)
  end

  if user = args[:as]
    if (evars = args[:environment].reject {|k,v| v.nil?}.map {|k,v| "#{k}=#{v}"}) && !evars.empty?
      env = "env #{evars.join(' ')}"
    else
      env = ''
    end
    
    cmd = "sudo -H -u #{user} #{env} #{cmd}"
  end

  # debug "running #{cmd} #{massaged_args(args).inspect}"
  
  pwrite, pread, perror, pexception = IO.pipe, IO.pipe, IO.pipe, IO.pipe

  verbose = $VERBOSE
  begin
    $VERBOSE = nil
    pexception.last.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)

    cid = fork {
      pwrite.last.close
      STDIN.reopen pwrite.first
      pwrite.first.close

      pread.first.close
      STDOUT.reopen pread.last
      pread.last.close

      perror.first.close
      STDERR.reopen perror.last
      perror.last.close

      STDOUT.sync = STDERR.sync = true

      if args[:group]
        Process.egid = args[:group]
        Process.gid = args[:group]
      end

      if args[:user]
        Process.euid = args[:user]
        Process.uid = args[:user]
      end

      # Copy the specified environment across to the child's environment.
      # Keys with `nil` values are deleted from the environment.
      args[:environment].each do |key,value|
        if value.nil?
          ENV.delete(key.to_s)
        else
          ENV[key.to_s] = value
        end
      end

      if args[:umask]
        umask = ((args[:umask].respond_to?(:oct) ? args[:umask].oct : args[:umask].to_i) & 007777)
        File.umask(umask)
      end

      if args[:cwd]
        Dir.chdir args[:cwd]
      end
      
      begin
        if cmd.kind_of?(Array)
          exec(*cmd)
        else
          exec(cmd)
        end
        raise 'forty-two' 
      rescue Exception => e
        Marshal.dump(e, pexception.last)
        pexception.last.flush
      end
      pexception.last.close unless (pexception.last.closed?)
      exit!
    }
  ensure
    $VERBOSE = verbose
  end

  [pwrite.first, pread.last, perror.last, pexception.last].each{|fd| fd.close}

  begin
    e = Marshal.load pexception.first
    raise(Exception === e ? e : "unknown failure!")
  rescue EOFError # If we get an EOF error, then the exec was successful
    42
  ensure
    pexception.first.close
  end

  pwrite.last.sync = true

  pi = [pwrite.last, pread.first, perror.first]

  if b 
    begin
      if args[:stream]
        b[cid, *pi]
        ShellResult.new(Process.waitpid2(cid).last, args)
      else
        o = StringIO.new
        e = StringIO.new

        if args[:input]
          pi[0].puts args[:input]
        end

        pi[0].close
        
        stdout = pi[1]
        stderr = pi[2]

        stdout.sync = true
        stderr.sync = true

        stdout.fcntl(Fcntl::F_SETFL, pi[1].fcntl(Fcntl::F_GETFL) | Fcntl::O_NONBLOCK)
        stderr.fcntl(Fcntl::F_SETFL, pi[2].fcntl(Fcntl::F_GETFL) | Fcntl::O_NONBLOCK)
        
        stdout_finished = false
        stderr_finished = false
       
        results = nil

        while !stdout_finished || !stderr_finished
          begin
            channels_to_watch = []
            channels_to_watch << stdout if !stdout_finished
            channels_to_watch << stderr if !stderr_finished
            ready = IO.select(channels_to_watch, nil, nil, 1.0)
          rescue Errno::EAGAIN
            results = Process.waitpid2(cid, Process::WNOHANG)
            if results
              stdout_finished = true
              stderr_finished = true 
            end
          end

          if ready && ready.first.include?(stdout)
            line = results ? stdout.gets(nil) : stdout.gets
            if line
              o.write(line)
            else
              stdout_finished = true
            end
          end
          if ready && ready.first.include?(stderr)
            line = results ? stderr.gets(nil) : stderr.gets
            if line
              e.write(line)
            else
              stderr_finished = true
            end
          end
        end
        results = Process.waitpid2(cid).last unless results
        o.rewind
        e.rewind
        b[cid, pi[0], o, e]

        ShellResult.new(results, args)
      end
    ensure
      pi.each{|fd| fd.close unless fd.closed?}
    end
  else
    [cid, pw.last, pr.first, pe.first]
  end
end

#run ⇒ Object 



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# File 'lib/common_mob/shell.rb', line 55

def run
  execute.ensure_ok!
end

#to_s ⇒ Object 



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# File 'lib/common_mob/shell.rb', line 63

def to_s
  result = execute
  if result.ok?
    result.stdout.chomp
  else
    ''
  end
end