client/common_lib/utils.py

#!/usr/bin/python
#
# Copyright 2008 Google Inc. Released under the GPL v2

import os, pickle, random, re, select, shutil, signal, StringIO, subprocess
import sys, time, textwrap, urllib, urlparse
import error, barrier


def read_one_line(filename):
	return open(filename, 'r').readline().strip()


def write_one_line(filename, str):
	open(filename, 'w').write(str.rstrip() + "\n")


def read_keyval(path):
	"""
	Read a key-value pair format file into a dictionary, and return it.
	Takes either a filename or directory name as input. If it's a
	directory name, we assume you want the file to be called keyval.
	"""
	if os.path.isdir(path):
		path = os.path.join(path, 'keyval')
	keyval = {}
	for line in open(path):
		line = re.sub('#.*', '', line.rstrip())
		if not re.search(r'^[-\w]+=', line):
			raise ValueError('Invalid format line: %s' % line)
		key, value = line.split('=', 1)
		if re.search('^\d+$', value):
			value = int(value)
		elif re.search('^(\d+\.)?\d+$', value):
			value = float(value)
		keyval[key] = value
	return keyval


def write_keyval(path, dictionary, type_tag=None):
	"""
	Write a key-value pair format file out to a file. This uses append
	mode to open the file, so existing text will not be overwritten or
	reparsed.

	If type_tag is None, then the key must be composed of alphanumeric
	characters (or dashes+underscores). However, if type-tag is not
	null then the keys must also have "{type_tag}" as a suffix. At
	the moment the only valid values of type_tag are "attr" and "perf".
	"""
	if os.path.isdir(path):
		path = os.path.join(path, 'keyval')
	keyval = open(path, 'a')

	if type_tag is None:
		key_regex = re.compile(r'^[-\w]+$')
	else:
		if type_tag not in ('attr', 'perf'):
			raise ValueError('Invalid type tag: %s' % type_tag)
		escaped_tag = re.escape(type_tag)
		key_regex = re.compile(r'^[-\w]+\{%s\}$' % escaped_tag)
	try:
		for key, value in dictionary.iteritems():
			if not key_regex.search(key):
				raise ValueError('Invalid key: %s' % key)
			keyval.write('%s=%s\n' % (key, value))
	finally:
		keyval.close()


def is_url(path):
	"""Return true if path looks like a URL"""
	# for now, just handle http and ftp
	url_parts = urlparse.urlparse(path)
	return (url_parts[0] in ('http', 'ftp'))


def get_file(src, dest, permissions=None):
	"""Get a file from src, which can be local or a remote URL"""
	if (src == dest):
		return
	if (is_url(src)):
		print 'PWD: ' + os.getcwd()
		print 'Fetching \n\t', src, '\n\t->', dest
		try:
			urllib.urlretrieve(src, dest)
		except IOError, e:
			raise error.AutotestError('Unable to retrieve %s (to %s)'
					    % (src, dest), e)
	else:
		shutil.copyfile(src, dest)
	if permissions:
		os.chmod(dest, permissions)
	return dest


def unmap_url(srcdir, src, destdir='.'):
	"""
	Receives either a path to a local file or a URL.
	returns either the path to the local file, or the fetched URL

	unmap_url('/usr/src', 'foo.tar', '/tmp')
				= '/usr/src/foo.tar'
	unmap_url('/usr/src', 'http://site/file', '/tmp')
				= '/tmp/file'
				(after retrieving it)
	"""
	if is_url(src):
		url_parts = urlparse.urlparse(src)
		filename = os.path.basename(url_parts[2])
		dest = os.path.join(destdir, filename)
		return get_file(src, dest)
	else:
		return os.path.join(srcdir, src)


def update_version(srcdir, preserve_srcdir, new_version, install,
		   *args, **dargs):
	"""
	Make sure srcdir is version new_version

	If not, delete it and install() the new version.

	In the preserve_srcdir case, we just check it's up to date,
	and if not, we rerun install, without removing srcdir
	"""
	versionfile = os.path.join(srcdir, '.version')
	install_needed = True

	if os.path.exists(versionfile):
		old_version = pickle.load(open(versionfile))
		if old_version == new_version:
			install_needed = False

	if install_needed:
		if not preserve_srcdir and os.path.exists(srcdir):
			shutil.rmtree(srcdir)
		install(*args, **dargs)
		if os.path.exists(srcdir):
			pickle.dump(new_version, open(versionfile, 'w'))


def run(command, timeout=None, ignore_status=False,
	stdout_tee=None, stderr_tee=None):
	"""
	Run a command on the host.

	Args:
		command: the command line string
		timeout: time limit in seconds before attempting to
			kill the running process. The run() function
			will take a few seconds longer than 'timeout'
			to complete if it has to kill the process.
		ignore_status: do not raise an exception, no matter what
			the exit code of the command is.
		stdout_tee: optional file-like object to which stdout data
		            will be written as it is generated (data will still
			    be stored in result.stdout)
		stderr_tee: likewise for stderr

	Returns:
		a CmdResult object

	Raises:
		CmdError: the exit code of the command
			execution was not 0
	"""
	return join_bg_job(run_bg(command), command, timeout, ignore_status,
			   stdout_tee, stderr_tee)


def run_bg(command):
	"""Run the command in a subprocess and return the subprocess."""
	result = CmdResult(command)
	sp = subprocess.Popen(command, stdout=subprocess.PIPE,
			      stderr=subprocess.PIPE,
			      shell=True, executable="/bin/bash")
	return sp, result


def join_bg_job(bg_job, command, timeout=None, ignore_status=False,
	stdout_tee=None, stderr_tee=None):
	"""Join the subprocess with the current thread. See run description."""
	sp, result = bg_job
	stdout_file = StringIO.StringIO()
	stderr_file = StringIO.StringIO()
	(ret, timeouterr) = (0, False)

	try:
		# We are holding ends to stdin, stdout pipes
		# hence we need to be sure to close those fds no mater what
		start_time = time.time()
		(ret, timeouterr) = _wait_for_command(sp, start_time,
					timeout, stdout_file, stderr_file,
					stdout_tee, stderr_tee)
		result.exit_status = ret
		result.duration = time.time() - start_time
		# don't use os.read now, so we get all the rest of the output
		_process_output(sp.stdout, stdout_file, stdout_tee,
				use_os_read=False)
		_process_output(sp.stderr, stderr_file, stderr_tee,
				use_os_read=False)
	finally:
		# close our ends of the pipes to the sp no matter what
		sp.stdout.close()
		sp.stderr.close()

	result.stdout = stdout_file.getvalue()
	result.stderr = stderr_file.getvalue()

	if result.exit_status != 0:
		if timeouterr:
			raise error.CmdError(command, result, "Command did not "
					     "complete within %d seconds" % timeout)
		elif not ignore_status:
			raise error.CmdError(command, result,
					     "Command returned non-zero exit status")

	return result

# this returns a tuple with the return code and a flag to specify if the error
# is due to the process not terminating within timeout
def _wait_for_command(subproc, start_time, timeout, stdout_file, stderr_file,
		      stdout_tee, stderr_tee):
	if timeout:
		stop_time = start_time + timeout
		time_left = stop_time - time.time()
	else:
		time_left = None # so that select never times out
	while not timeout or time_left > 0:
		# select will return when stdout is ready (including when it is
		# EOF, that is the process has terminated).
		ready, _, _ = select.select([subproc.stdout, subproc.stderr],
					     [], [], time_left)
		# os.read() has to be used instead of
		# subproc.stdout.read() which will otherwise block
		if subproc.stdout in ready:
			_process_output(subproc.stdout, stdout_file,
					stdout_tee)
		if subproc.stderr in ready:
			_process_output(subproc.stderr, stderr_file,
					stderr_tee)

		exit_status_indication = subproc.poll()

		if exit_status_indication is not None:
			return (exit_status_indication, False)

		if timeout:
			time_left = stop_time - time.time()

	# the process has not terminated within timeout,
	# kill it via an escalating series of signals.
	if exit_status_indication is None:
		exit_status_indication = nuke_subprocess(subproc)

	return (exit_status_indication, True)


def _process_output(pipe, fbuffer, teefile=None, use_os_read=True):
	if use_os_read:
		data = os.read(pipe.fileno(), 1024)
	else:
		data = pipe.read()
	fbuffer.write(data)
	if teefile:
		teefile.write(data)
		teefile.flush()


def nuke_subprocess(subproc):
       # the process has not terminated within timeout,
       # kill it via an escalating series of signals.
       signal_queue = [signal.SIGTERM, signal.SIGKILL]
       for sig in signal_queue:
	       try:
		       os.kill(subproc.pid, sig)
	       # The process may have died before we could kill it.
	       except OSError:
		       pass

	       for i in range(5):
		       rc = subproc.poll()
		       if rc != None:
			       return rc
		       time.sleep(1)


def nuke_pid(pid):
       # the process has not terminated within timeout,
       # kill it via an escalating series of signals.
       signal_queue = [signal.SIGTERM, signal.SIGKILL]
       for sig in signal_queue:
	       try:
		       os.kill(pid, sig)

	       # The process may have died before we could kill it.
	       except OSError:
		       pass

	       try:
		       for i in range(5):
			       status = os.waitpid(pid, os.WNOHANG)[0]
			       if status == pid:
				       return
			       time.sleep(1)

		       if status != pid:
			       raise error.AutoservRunError('Could not kill %d'
				       % pid, None)

	       # the process died before we join it.
	       except OSError:
		       pass


def _process_output(pipe, fbuffer, teefile=None, use_os_read=True):
	if use_os_read:
		data = os.read(pipe.fileno(), 1024)
	else:
		data = pipe.read()
	fbuffer.write(data)
	if teefile:
		teefile.write(data)
		teefile.flush()


def system(command, timeout=None, ignore_status=False):
	return run(command, timeout, ignore_status,
		stdout_tee=sys.stdout, stderr_tee=sys.stderr).exit_status


def system_output(command, timeout=None, ignore_status=False,
		  retain_output=False):
	if retain_output:
		out = run(command, timeout, ignore_status,
			  stdout_tee=sys.stdout, stderr_tee=sys.stderr).stdout
	else:
		out = run(command, timeout, ignore_status).stdout
	if out[-1:] == '\n': out = out[:-1]
	return out

"""
This function is used when there is a need to run more than one
job simultaneously starting exactly at the same time. It basically returns
a modified control file (containing the synchronization code prepended)
whenever it is ready to run the control file. The synchronization
is done using barriers to make sure that the jobs start at the same time.

Here is how the synchronization is done to make sure that the tests
start at exactly the same time on the client.
sc_bar is a server barrier and s_bar, c_bar are the normal barriers

                  Job1              Job2         ......      JobN
 Server:   |                        sc_bar
 Server:   |                        s_bar        ......      s_bar
 Server:   |      at.run()         at.run()      ......      at.run()
 ----------|------------------------------------------------------
 Client    |      sc_bar
 Client    |      c_bar             c_bar        ......      c_bar
 Client    |    <run test>         <run test>    ......     <run test>


PARAMS:
   control_file : The control file which to which the above synchronization
                  code would be prepended to
   host_name    : The host name on which the job is going to run
   host_num (non negative) : A number to identify the machine so that we have
                  different sets of s_bar_ports for each of the machines.
   instance     : The number of the job
   num_jobs     : Total number of jobs that are going to run in parallel with
                  this job starting at the same time
   port_base    : Port number that is used to derive the actual barrier ports.

RETURN VALUE:
    The modified control file.

"""
def get_sync_control_file(control, host_name, host_num,
			  instance, num_jobs, port_base=63100):
	sc_bar_port = port_base
	c_bar_port = port_base
	if host_num < 0:
		print "Please provide a non negative number for the host"
		return None
	s_bar_port = port_base + 1 + host_num # The set of s_bar_ports are
                                              # the same for a given machine

	sc_bar_timeout = 180
	s_bar_timeout = c_bar_timeout = 120

	# The barrier code snippet is prepended into the conrol file
	# dynamically before at.run() is called finally.
	control_new = []

       	# jobid is the unique name used to identify the processes
	# trying to reach the barriers
	jobid = "%s#%d" % (host_name, instance)

	rendv = []
	# rendvstr is a temp holder for the rendezvous list of the processes
	for n in range(num_jobs):
		rendv.append("'%s#%d'" % (host_name, n))
	rendvstr = ",".join(rendv)

	if instance == 0:
		# Do the setup and wait at the server barrier
		# Clean up the tmp and the control dirs for the first instance
		control_new.append('if os.path.exists(job.tmpdir):')
		control_new.append("\t system('umount -f %s > /dev/null"
				   "2> /dev/null' % job.tmpdir,"
				   "ignore_status=True)")
		control_new.append("\t system('rm -rf ' + job.tmpdir)")
		control_new.append(
		    'b0 = job.barrier("%s", "sc_bar", %d, port=%d)'
		    % (jobid, sc_bar_timeout, sc_bar_port))
		control_new.append(
		'b0.rendevous_servers("PARALLEL_MASTER", "%s")'
		 % jobid)

	elif instance == 1:
		# Wait at the server barrier to wait for instance=0
		# process to complete setup
		b0 = barrier.barrier("PARALLEL_MASTER", "sc_bar", sc_bar_timeout,
			     port=sc_bar_port)
		b0.rendevous_servers("PARALLEL_MASTER", jobid)

		if(num_jobs > 2):
			b1 = barrier.barrier(jobid, "s_bar", s_bar_timeout,
				     port=s_bar_port)
	        	b1.rendevous(rendvstr)

	else:
		# For the rest of the clients
		b2 = barrier.barrier(jobid, "s_bar", s_bar_timeout, port=s_bar_port)
		b2.rendevous(rendvstr)

	# Client side barrier for all the tests to start at the same time
	control_new.append('b1 = job.barrier("%s", "c_bar", %d, port=%d)'
			% (jobid, c_bar_timeout, c_bar_port))
	control_new.append("b1.rendevous(%s)" % rendvstr)

	# Stick in the rest of the control file
	control_new.append(control)

	return "\n".join(control_new)


class CmdResult(object):
	"""
	Command execution result.

	command:     String containing the command line itself
	exit_status: Integer exit code of the process
	stdout:      String containing stdout of the process
	stderr:      String containing stderr of the process
	duration:    Elapsed wall clock time running the process
	"""


	def __init__(self, command = None):
		self.command = command
		self.exit_status = None
		self.stdout = ""
		self.stderr = ""
		self.duration = 0


	def __repr__(self):
		wrapper = textwrap.TextWrapper(width = 78,
					       initial_indent="\n    ",
					       subsequent_indent="    ")

		stdout = self.stdout.rstrip()
		if stdout:
			stdout = "\nstdout:\n%s" % stdout

		stderr = self.stderr.rstrip()
		if stderr:
			stderr = "\nstderr:\n%s" % stderr

		return ("* Command: %s\n"
			"Exit status: %s\n"
			"Duration: %s\n"
			"%s"
			"%s"
			% (wrapper.fill(self.command), self.exit_status,
			self.duration, stdout, stderr))


class run_randomly:


	def __init__(self):
		self.test_list = []


	def add(self, *args, **dargs):
		test = (args, dargs)
		self.test_list.append(test)


	def run(self, fn):
		while self.test_list:
			test_index = random.randint(0, len(self.test_list)-1)
			(args, dargs) = self.test_list.pop(test_index)
			fn(*args, **dargs)