#!/usr/local/bin/python

import sys, os
import re

import tempfile
import subprocess
import logging 
import time
import signal

from proxy_segment import proxy_segment
from service_error import service_error

class start_segment(proxy_segment):
    """
    This starts an experiment on an emulab accessed remotely via ssh.  Most of
    the experiment constuction has been done by the emulab_access object.  This
    just does the wrangling of the emulab commands and collected the node to
    physical mapping.  The routine throws service errors.
    """

    def __init__(self, log=None, keyfile=None, debug=False, boss=None, 
	    cert=None):
	proxy_segment.__init__(self, log=log, keyfile=keyfile, debug=debug)
	self.null = """
set ns [new Simulator]
source tb_compat.tcl

set a [$ns node]

$ns rtproto Session
$ns run 
"""
	self.node = { }

    def get_state(self, user, host, pid, eid):
	"""
	Return the state of the experiment as reported by emulab
	"""
	# command to test experiment state
	expinfo_exec = "/usr/testbed/bin/expinfo"  
	# Regular expressions to parse the expinfo response
	state_re = re.compile("State:\s+(\w+)")
	no_exp_re = re.compile("^No\s+such\s+experiment")
	swapping_re = re.compile("^No\s+information\s+available.")
	state = None    # Experiment state parsed from expinfo
	# The expinfo ssh command.  Note the identity restriction to use
	# only the identity provided in the pubkey given.
	cmd = [self.ssh_exec, '-o', 'IdentitiesOnly yes', '-o', 
		'StrictHostKeyChecking no', '-i', 
		self.ssh_privkey_file, "%s@%s" % (user, host), 
		expinfo_exec, pid, eid]

	dev_null = None
	try:
	    dev_null = open("/dev/null", "a")
	except EnvironmentError, e:
	    self.log.error("[get_state]: can't open /dev/null: %s" %e)

	if self.debug:
	    state = 'swapped'
	    rv = 0
	else:
	    self.log.debug("Checking state")
	    status = subprocess.Popen(cmd, stdout=subprocess.PIPE,
		    stderr=dev_null, close_fds=True)
	    for line in status.stdout:
		m = state_re.match(line)
		if m: state = m.group(1)
		else:
		    for reg, st in ((no_exp_re, "none"),
			    (swapping_re, "swapping")):
			m = reg.match(line)
			if m: state = st
	    rv = status.wait()

	# If the experiment is not present the subcommand returns a
	# non-zero return value.  If we successfully parsed a "none"
	# outcome, ignore the return code.
	if rv != 0 and state != 'none':
	    raise service_error(service_error.internal,
		    "Cannot get status of segment:%s/%s" % (pid, eid))
	elif state not in ('active', 'swapped', 'swapping', 'none'):
	    raise service_error(service_error.internal,
		    "Cannot get status of segment:%s/%s" % (pid, eid))
	else:
	    self.log.debug("State is %s" % state)
	    return state


    def get_mapping(self, user, host, pid, eid):
	"""
	Get the physical to virtual mapping from the expinfo command and save
	it in the self.map member.
	"""
	# command to test experiment state
	expinfo_exec = "/usr/testbed/bin/expinfo"  
	# The expinfo ssh command.  Note the identity restriction to use
	# only the identity provided in the pubkey given.
	cmd = [self.ssh_exec, '-o', 'IdentitiesOnly yes', '-o', 
		'StrictHostKeyChecking no', '-i', 
		self.ssh_privkey_file, "%s@%s" % (user, host), 
		expinfo_exec, '-m', pid, eid]

	dev_null = None
	try:
	    dev_null = open("/dev/null", "a")
	except EnvironmentError, e:
	    self.log.error("[get_mapping]: can't open /dev/null: %s" %e)

	if self.debug:
	    rv = 0
	else:
	    self.log.debug("Getting mapping for %s %s" % (pid, eid))
	    phys_start = re.compile('^Physical\s+Node\s+Mapping')
	    phys_line = re.compile('(\S+)(\s+\S+)*\s+(\S+)')
	    phys_end = re.compile('^$')
	    status = subprocess.Popen(cmd, stdout=subprocess.PIPE,
		    stderr=dev_null, close_fds=True)

	    # Parse the info output.  Format:
	    #
	    # stuff
	    # Physical Node Mapping:
	    # ID              Type         OS              Physical    
	    # --------------- ------------ --------------- ------------
	    # virtual         dummy        dummy           physical
	    #
	    foundit = False
	    skip = 0
	    for line in status.stdout:
		if phys_start.match(line):
		    skip = 2
		    foundit = True
		elif not foundit:
		    continue
		elif skip > 0:
		    skip -= 1
		elif phys_end.match(line):
		    break
		else:
		    m = phys_line.match(line.strip())
		    if m: self.node[m.group(1)] = m.group(3)
		    else: self.log.warn(
			    "Matching failed while parsing node mapping: " +\
				    "line %s" % line)
	    rv = status.wait()

	# If the experiment is not present the subcommand returns a
	# non-zero return value.  If we successfully parsed a "none"
	# outcome, ignore the return code.
	if rv != 0 :
	    raise service_error(service_error.internal,
		    "Cannot get node mapping of segment:%s/%s" % (pid, eid))
	else:
	    return True


    def make_null_experiment(self, user, host, pid, eid, tmpdir, gid=None):
	"""
	Create a null copy of the experiment so that we capture any logs there
	if the modify fails.  Emulab software discards the logs from a failed
	startexp
	"""

	if gid is not None: gparam = '-g %s' % gid
	else: gparam = ''

	try:
	    f = open("%s/null.tcl" % tmpdir, "w")
	    print >>f, self.null
	    f.close()
	except EnvironmentError, e:
	    raise service_error(service_error.internal,
		    "Cannot stage tarfile/rpm: %s" % e.strerror)

	if not self.scp_file("%s/null.tcl" % tmpdir, user, host):
	    return False
	self.log.info("[start_segment]: Creating %s" % eid)
	timedout = False
	try:
	    if not self.ssh_cmd(user, host,
		    ("/usr/testbed/bin/startexp -i -f -w -p %s " + 
		    "-e %s %s null.tcl") % (pid, eid, gparam), "startexp",
		    timeout=60 * 10):
		return False
	except self.ssh_cmd_timeout:
	    timedout = True

	if timedout:
	    state = self.get_state(user, host, pid, eid)
	    if state != "swapped":
		return False
	return True

    def set_up_experiment_filespace(self, user, host, pid, eid, tmpdir):
	"""
	Send all the software and configuration files into the experiment's
	file space.  To reduce the number of ssh connections, we script many
	changes and execute the script.
	"""
	# Configuration directories on the remote machine
	proj_dir = "/proj/%s/exp/%s/tmp" % (pid, eid)
	softdir = "/proj/%s/software/%s" % (pid, eid)
	# Local software dir
	lsoftdir = "%s/software" % tmpdir

	# Open up a temporary file to contain a script for setting up the
	# filespace for the new experiment.
	self.log.info("[start_segment]: creating script file")
	try:
	    sf, scriptname = tempfile.mkstemp()
	    scriptfile = os.fdopen(sf, 'w')
	except EnvironmentError:
	    return False

	scriptbase = os.path.basename(scriptname)

	# Script the filesystem changes
	print >>scriptfile, "/bin/rm -rf %s" % proj_dir
	# Clear and create the software directory
	print >>scriptfile, "/bin/rm -rf %s/*" % softdir
	print >>scriptfile, 'mkdir -p %s' % proj_dir
	if os.path.isdir(lsoftdir):
	    print >>scriptfile, 'mkdir -p %s' % softdir
	print >>scriptfile, "rm -f %s" % scriptbase
	scriptfile.close()

	# Move the script to the remote machine
	# XXX: could collide tempfile names on the remote host
	if self.scp_file(scriptname, user, host, scriptbase):
	    os.remove(scriptname)
	else:
	    return False

	# Execute the script (and the script's last line deletes it)
	if not self.ssh_cmd(user, host, "sh -x %s" % scriptbase):
	    return False

	for f in os.listdir(tmpdir):
	    if not os.path.isdir("%s/%s" % (tmpdir, f)):
		if not self.scp_file("%s/%s" % (tmpdir, f), user, host,
			"%s/%s" % (proj_dir, f)):
		    return False
	if os.path.isdir(lsoftdir):
	    for f in os.listdir(lsoftdir):
		if not os.path.isdir("%s/%s" % (lsoftdir, f)):
		    if not self.scp_file("%s/%s" % (lsoftdir, f), 
			    user, host, "%s/%s" % (softdir, f)):
			return False
	return True

    def swap_in(self, user, host, pid, eid):
	"""
	Swap experiment in.  This includes code to cope with the experiment
	swaping command timing out, but the experiment being swapped in
	successfully.
	"""
	self.log.info("[start_segment]: Swapping %s in" % eid)
	timedout = False
	try:
	    if not self.ssh_cmd(user, host,
		    "/usr/testbed/bin/swapexp -w %s %s in" % (pid, eid),
		    "swapexp", timeout=25*60):
		return False
	except self.ssh_cmd_timeout:
	    timedout = True
       
	# If the command was terminated, but completed successfully,
	# report success.
	if timedout:
	    self.log.debug("[start_segment]: swapin timed out " +\
		    "checking state")
	    state = self.get_state(user, host, pid, eid)
	    self.log.debug("[start_segment]: state is %s" % state)
	    return state == 'active'

	return True


    def __call__(self, parent, eid, pid, user, tclfile, tmpdir, timeout=0,
	    gid=None):
	"""
	Start a sub-experiment on a federant.

	Get the current state, and terminate the experiment if it exists. The
	group membership of the experiment is difficult to determine or change,
	so start with a clean slate.  Create a new one and ship data
	and configs and start the experiment.  There are small ordering
	"""
	# ops node in the federant
	host = "%s%s" % (parent.ops, parent.domain)
	state = self.get_state(user, host, pid, eid)

	if not self.scp_file(tclfile, user, host):
	    return False
	
	if state != 'none':
	    self.ssh_cmd(user, host, 
		    "/usr/testbed/bin/endexp -w %s %s" % (pid, eid))

	# Put a dummy in place to capture logs, and establish an experiment
	# directory.
	if not self.make_null_experiment(user, host, pid, eid, tmpdir, gid):
	    return False

	if not self.set_up_experiment_filespace(user, host, pid, eid, tmpdir):
	    return False

	# With the filespace in place, we can modify and swap in.
	self.log.info("[start_segment]: Modifying %s" % eid)
	try:
	    if not self.ssh_cmd(user, host,
		    "/usr/testbed/bin/modexp -r -s -w %s %s %s" % \
			    (pid, eid, tclfile.rpartition('/')[2]),
		    "modexp", timeout= 60 * 10):
		return False
	except self.ssh_cmd_timeout:
	    self.log.error("Modify command failed to complete in time")
	    # There's really no way to see if this succeeded or failed, so
	    # if it hangs, assume the worst.
	    return False

	if not self.swap_in(user, host, pid, eid):
	    self.log.error("swap in failed")
	    return False
	# Everything has gone OK.
	self.get_mapping(user, host, pid,eid)
	return True

class stop_segment(proxy_segment):
    def __init__(self, log=None, keyfile=None, debug=False, boss=None, cert=None):
	proxy_segment.__init__(self, log=log, keyfile=keyfile, debug=debug)

    def __call__(self, parent, user, pid, eid, gid=None, terminate=False):
	"""
	Stop a sub experiment by calling swapexp on the federant
	"""
	host = "%s%s" % (parent.ops, parent.domain)
	self.log.info("[stop_segment]: Stopping %s" % eid)
	rv = False
	try:
	    # Clean out tar files: we've gone over quota in the past
	    self.ssh_cmd(user, host, "rm -rf /proj/%s/software/%s" % \
		    (pid, eid))
	    rv = self.ssh_cmd(user, host,
		    "/usr/testbed/bin/swapexp -w %s %s out" % (pid, eid))
	    if terminate:
		rv = self.ssh_cmd(user, host,
			"/usr/testbed/bin/endexp -w %s %s" % (pid, eid))
	except self.ssh_cmd_timeout:
	    rv = False
	return rv