utils/command_executer.py

# Copyright 2011 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Utilities to run commands in outside/inside chroot and on the board."""

import getpass
import os
import re
import select
import signal
import subprocess
import sys
import tempfile
import time

import logger
import misc

mock_default = False

LOG_LEVEL = ("none", "quiet", "average", "verbose")

def InitCommandExecuter(mock=False):
  global mock_default
  # Whether to default to a mock command executer or not
  mock_default = mock


def GetCommandExecuter(logger_to_set=None, mock=False, log_level="verbose"):
  # If the default is a mock executer, always return one.
  if mock_default or mock:
    return MockCommandExecuter(log_level, logger_to_set)
  else:
    return CommandExecuter(log_level, logger_to_set)


class CommandExecuter(object):
  """Provides several methods to execute commands on several environments."""

  def __init__(self, log_level, logger_to_set=None):
    self.log_level = log_level
    if log_level == "none":
      self.logger = None
    else:
      if logger_to_set is not None:
        self.logger = logger_to_set
      else:
        self.logger = logger.GetLogger()

  def GetLogLevel(self):
    return self.log_level

  def SetLogLevel(self, log_level):
    self.log_level = log_level

  def RunCommand(self, cmd, return_output=False, machine=None,
                 username=None, command_terminator=None,
                 command_timeout=None,
                 terminated_timeout=10,
                 print_to_console=True):
    """Run a command."""

    cmd = str(cmd)

    if self.log_level == "quiet":
      print_to_console = False

    if self.log_level == "verbose":
      self.logger.LogCmd(cmd, machine, username, print_to_console)
    elif self.logger:
      self.logger.LogCmdToFileOnly(cmd, machine, username)
    if command_terminator and command_terminator.IsTerminated():
      if self.logger:
        self.logger.LogError("Command was terminated!", print_to_console)
      if return_output:
        return [1, "", ""]
      else:
        return 1

    if machine is not None:
      user = ""
      if username is not None:
        user = username + "@"
      cmd = "ssh -t -t %s%s -- '%s'" % (user, machine, cmd)

    # We use setsid so that the child will have a different session id
    # and we can easily kill the process group. This is also important
    # because the child will be disassociated from the parent terminal.
    # In this way the child cannot mess the parent's terminal.
    p = subprocess.Popen(cmd, stdout=subprocess.PIPE,
                         stderr=subprocess.PIPE, shell=True,
                         preexec_fn=os.setsid)

    full_stdout = ""
    full_stderr = ""

    # Pull output from pipes, send it to file/stdout/string
    out = err = None
    pipes = [p.stdout, p.stderr]

    my_poll = select.poll()
    my_poll.register(p.stdout, select.POLLIN)
    my_poll.register(p.stderr, select.POLLIN)

    terminated_time = None
    started_time = time.time()

    while len(pipes):
      if command_terminator and command_terminator.IsTerminated():
        os.killpg(os.getpgid(p.pid), signal.SIGTERM)
        if self.logger:
          self.logger.LogError("Command received termination request. "
                               "Killed child process group.",
                               print_to_console)
        break

      l = my_poll.poll(100)
      for (fd, _) in l:
        if fd == p.stdout.fileno():
          out = os.read(p.stdout.fileno(), 16384)
          if return_output:
            full_stdout += out
          if self.logger:
            self.logger.LogCommandOutput(out, print_to_console)
          if out == "":
            pipes.remove(p.stdout)
            my_poll.unregister(p.stdout)
        if fd == p.stderr.fileno():
          err = os.read(p.stderr.fileno(), 16384)
          if return_output:
            full_stderr += err
          if self.logger:
            self.logger.LogCommandError(err, print_to_console)
          if err == "":
            pipes.remove(p.stderr)
            my_poll.unregister(p.stderr)

      if p.poll() is not None:
        if terminated_time is None:
          terminated_time = time.time()
        elif (terminated_timeout is not None and
              time.time() - terminated_time > terminated_timeout):
          if self.logger:
            self.logger.LogWarning("Timeout of %s seconds reached since "
                                   "process termination."
                                   % terminated_timeout, print_to_console)
          break

      if (command_timeout is not None and
          time.time() - started_time > command_timeout):
        os.killpg(os.getpgid(p.pid), signal.SIGTERM)
        if self.logger:
          self.logger.LogWarning("Timeout of %s seconds reached since process"
                                 "started. Killed child process group."
                                 % command_timeout, print_to_console)
        break

      if out == err == "":
        break

    p.wait()
    if return_output:
      return (p.returncode, full_stdout, full_stderr)
    return p.returncode

  def RemoteAccessInitCommand(self, chromeos_root, machine):
    command = ""
    command += "\nset -- --remote=" + machine
    command += "\n. " + chromeos_root + "/src/scripts/common.sh"
    command += "\n. " + chromeos_root + "/src/scripts/remote_access.sh"
    command += "\nTMP=$(mktemp -d)"
    command += "\nFLAGS \"$@\" || exit 1"
    command += "\nremote_access_init"
    return command

  def WriteToTempShFile(self, contents):
    handle, command_file = tempfile.mkstemp(prefix=os.uname()[1],
                                            suffix=".sh")
    os.write(handle, "#!/bin/bash\n")
    os.write(handle, contents)
    os.close(handle)
    return command_file


  def CrosLearnBoard(self, chromeos_root, machine):
    command = self.RemoteAccessInitCommand(chromeos_root, machine)
    command += "\nlearn_board"
    command += "\necho ${FLAGS_board}"
    retval, output, _ = self.RunCommand(command, True)
    if self.logger:
      self.logger.LogFatalIf(retval, "learn_board command failed")
    elif retval:
      sys.exit(1)
    return output.split()[-1]

  def CrosRunCommand(self, cmd, return_output=False, machine=None,
                     command_terminator=None,
                     chromeos_root=None, command_timeout=None,
                     terminated_timeout=10, print_to_console=True):
    """Run a command on a chromeos box"""

    if self.log_level != "verbose":
      print_to_console = False

    if self.logger:
      self.logger.LogCmd(cmd, print_to_console=print_to_console)
      self.logger.LogFatalIf(not machine, "No machine provided!")
      self.logger.LogFatalIf(not chromeos_root, "chromeos_root not given!")
    else:
      if not chromeos_root or not machine:
        sys.exit(1)
    chromeos_root = os.path.expanduser(chromeos_root)

    # Write all commands to a file.
    command_file = self.WriteToTempShFile(cmd)
    retval = self.CopyFiles(command_file, command_file,
                            dest_machine=machine,
                            command_terminator=command_terminator,
                            chromeos_root=chromeos_root,
                            dest_cros=True,
                            recursive=False,
                            print_to_console=print_to_console)
    if retval:
      if self.logger:
        self.logger.LogError("Could not run remote command on machine."
                             " Is the machine up?")
      return retval

    command = self.RemoteAccessInitCommand(chromeos_root, machine)
    command += "\nremote_sh bash %s" % command_file
    command += "\nl_retval=$?; echo \"$REMOTE_OUT\"; exit $l_retval"
    retval = self.RunCommand(command, return_output,
                             command_terminator=command_terminator,
                             command_timeout=command_timeout,
                             terminated_timeout=terminated_timeout,
                             print_to_console=print_to_console)
    if return_output:
      connect_signature = ("Initiating first contact with remote host\n" +
                           "Connection OK\n")
      connect_signature_re = re.compile(connect_signature)
      modded_retval = list(retval)
      modded_retval[1] = connect_signature_re.sub("", retval[1])
      return modded_retval
    return retval

  def ChrootRunCommand(self, chromeos_root, command, return_output=False,
                       command_terminator=None, command_timeout=None,
                       terminated_timeout=10,
                       print_to_console=True,
                       cros_sdk_options=""):

    if self.log_level != "verbose":
      print_to_console = False

    if self.logger:
      self.logger.LogCmd(command, print_to_console=print_to_console)

    handle, command_file = tempfile.mkstemp(dir=os.path.join(chromeos_root,
                                                             "src/scripts"),
                                            suffix=".sh",
                                            prefix="in_chroot_cmd")
    os.write(handle, "#!/bin/bash\n")
    os.write(handle, command)
    os.write(handle, "\n")
    os.close(handle)

    os.chmod(command_file, 0777)

    # if return_output is set, run a dummy command first to make sure that
    # the chroot already exists. We want the final returned output to skip
    # the output from chroot creation steps.
    if return_output:
      ret = self.RunCommand("cd %s; cros_sdk %s -- true" %
                            (chromeos_root, cros_sdk_options))
      if ret:
        return (ret, "", "")

    # Run command_file inside the chroot, making sure that any "~" is expanded
    # by the shell inside the chroot, not outside.
    command = ("cd %s; cros_sdk %s -- bash -c '%s/%s'" %
               (chromeos_root,
                cros_sdk_options,
                misc.CHROMEOS_SCRIPTS_DIR,
                os.path.basename(command_file)))
    ret = self.RunCommand(command, return_output,
                          command_terminator=command_terminator,
                          command_timeout=command_timeout,
                          terminated_timeout=terminated_timeout,
                          print_to_console=print_to_console)
    os.remove(command_file)
    return ret


  def RunCommands(self, cmdlist, return_output=False, machine=None,
                  username=None, command_terminator=None):
    cmd = " ;\n" .join(cmdlist)
    return self.RunCommand(cmd, return_output, machine, username,
                           command_terminator)

  def CopyFiles(self, src, dest, src_machine=None, dest_machine=None,
                src_user=None, dest_user=None, recursive=True,
                command_terminator=None,
                chromeos_root=None, src_cros=False, dest_cros=False,
                print_to_console=True):
    src = os.path.expanduser(src)
    dest = os.path.expanduser(dest)

    if recursive:
      src = src + "/"
      dest = dest + "/"

    if src_cros == True or dest_cros == True:
      if self.logger:
        self.logger.LogFatalIf(src_cros == dest_cros,
                               "Only one of src_cros and desc_cros can "
                               "be True.")
        self.logger.LogFatalIf(not chromeos_root, "chromeos_root not given!")
      elif src_cros == dest_cros or not chromeos_root:
        sys.exit(1)
      if src_cros == True:
        cros_machine = src_machine
      else:
        cros_machine = dest_machine

      command = self.RemoteAccessInitCommand(chromeos_root, cros_machine)
      ssh_command = ("ssh -p ${FLAGS_ssh_port}" +
                     " -o StrictHostKeyChecking=no" +
                     " -o UserKnownHostsFile=$(mktemp)" +
                     " -i $TMP_PRIVATE_KEY")
      rsync_prefix = "\nrsync -r -e \"%s\" " % ssh_command
      if dest_cros == True:
        command += rsync_prefix + "%s root@%s:%s" % (src, dest_machine, dest)
        return self.RunCommand(command,
                               machine=src_machine,
                               username=src_user,
                               command_terminator=command_terminator,
                               print_to_console=print_to_console)
      else:
        command += rsync_prefix + "root@%s:%s %s" % (src_machine, src, dest)
        return self.RunCommand(command,
                               machine=dest_machine,
                               username=dest_user,
                               command_terminator=command_terminator,
                               print_to_console=print_to_console)


    if dest_machine == src_machine:
      command = "rsync -a %s %s" % (src, dest)
    else:
      if src_machine is None:
        src_machine = os.uname()[1]
        src_user = getpass.getuser()
      command = "rsync -a %s@%s:%s %s" % (src_user, src_machine, src, dest)
    return self.RunCommand(command,
                           machine=dest_machine,
                           username=dest_user,
                           command_terminator=command_terminator,
                           print_to_console=print_to_console)


  def RunCommand2(self, cmd, cwd=None, line_consumer=None,
                  timeout=None, shell=True, join_stderr=True, env=None):
    """Run the command with an extra feature line_consumer.

    This version allow developers to provide a line_consumer which will be
    fed execution output lines.

    A line_consumer is a callback, which is given a chance to run for each
    line the execution outputs (either to stdout or stderr). The
    line_consumer must accept one and exactly one dict argument, the dict
    argument has these items -
      'line'   -  The line output by the binary. Notice, this string includes
                  the trailing '\n'.
      'output' -  Whether this is a stdout or stderr output, values are either
                  'stdout' or 'stderr'. When join_stderr is True, this value
                  will always be 'output'.
      'pobject' - The object used to control execution, for example, call
                  pobject.kill().

    Note: As this is written, the stdin for the process executed is
    not associated with the stdin of the caller of this routine.

    Args:
      cmd: Command in a single string.
      cwd: Working directory for execution.
      line_consumer: A function that will ba called by this function. See above
        for details.
      timeout: terminate command after this timeout.
      shell: Whether to use a shell for execution.
      join_stderr: Whether join stderr to stdout stream.
      env: Execution environment.

    Returns:
      Execution return code.

    Raises:
      child_exception: if fails to start the command process (missing
                       permission, no such file, etc)
    """

    class StreamHandler(object):
      """Internal utility class."""

      def __init__(self, pobject, fd, name, line_consumer):
        self._pobject = pobject
        self._fd = fd
        self._name = name
        self._buf = ''
        self._line_consumer = line_consumer

      def read_and_notify_line(self):
        t = os.read(fd, 1024)
        self._buf = self._buf + t
        self.notify_line()

      def notify_line(self):
        p = self._buf.find('\n')
        while p >= 0:
          self._line_consumer(line=self._buf[:p+1], output=self._name,
                              pobject=self._pobject)
          if p < len(self._buf) - 1:
            self._buf = self._buf[p+1:]
            p = self._buf.find('\n')
          else:
            self._buf = ''
            p = -1
            break

      def notify_eos(self):
        # Notify end of stream. The last line may not end with a '\n'.
        if self._buf != '':
          self._line_consumer(line=self._buf, output=self._name,
                              pobject=self._pobject)
          self._buf = ''

    if self.log_level == "verbose":
      self.logger.LogCmd(cmd)
    elif self.logger:
      self.logger.LogCmdToFileOnly(cmd)

    # We use setsid so that the child will have a different session id
    # and we can easily kill the process group. This is also important
    # because the child will be disassociated from the parent terminal.
    # In this way the child cannot mess the parent's terminal.
    pobject = subprocess.Popen(
        cmd, cwd=cwd, bufsize=1024, env=env, shell=shell,
        universal_newlines=True, stdout=subprocess.PIPE,
        stderr=subprocess.STDOUT if join_stderr else subprocess.PIPE,
        preexec_fn=os.setsid)

    # We provide a default line_consumer
    if line_consumer is None:
      line_consumer = lambda **d: None
    start_time = time.time()
    poll = select.poll()
    outfd = pobject.stdout.fileno()
    poll.register(outfd, select.POLLIN | select.POLLPRI)
    handlermap = {outfd: StreamHandler(pobject, outfd, 'stdout', line_consumer)}
    if not join_stderr:
      errfd = pobject.stderr.fileno()
      poll.register(errfd, select.POLLIN | select.POLLPRI)
      handlermap[errfd] = StreamHandler(
          pobject, errfd, 'stderr', line_consumer)
    while len(handlermap):
      readables = poll.poll(300)
      for (fd, evt) in readables:
        handler = handlermap[fd]
        if evt & (select.POLLPRI | select.POLLIN):
          handler.read_and_notify_line()
        elif evt & (select.POLLHUP | select.POLLERR | select.POLLNVAL):
          handler.notify_eos()
          poll.unregister(fd)
          del handlermap[fd]

      if timeout is not None and (time.time() - start_time > timeout):
        os.killpg(os.getpgid(pobject.pid), signal.SIGTERM)

    return pobject.wait()


class MockCommandExecuter(CommandExecuter):
  """Mock class for class CommandExecuter."""
  def __init__(self, log_level, logger_to_set=None):
    super(MockCommandExecuter, self).__init__(log_level, logger_to_set)

  def RunCommand(self, cmd, return_output=False, machine=None,
                 username=None, command_terminator=None,
                 command_timeout=None, terminated_timeout=10,
                 print_to_console=True):
    assert not command_timeout
    cmd = str(cmd)
    if machine is None:
      machine = "localhost"
    if username is None:
      username = "current"
    logger.GetLogger().LogCmd("(Mock) " + cmd, machine,
                              username, print_to_console)
    return 0


class CommandTerminator(object):
  """Object to request termination of a command in execution."""
  def __init__(self):
    self.terminated = False

  def Terminate(self):
    self.terminated = True

  def IsTerminated(self):
    return self.terminated