source: fedd/federation/local_emulab_segment.py @ d101c8c

#!/usr/local/bin/python

import sys, os
import re

import tempfile
import subprocess
import logging 
import time
import signal

import util

class local_emulab_segment:
    class cmd_timeout(RuntimeError): pass

    def __init__(self, log=None, keyfile=None, debug=False):
        self.log = log or logging.getLogger(\
                'fedd.access.proxy_emulab_segment')
        self.certfile = keyfile
        self.debug = debug
        self.cmd_timeout = local_emulab_segment.cmd_timeout

    def copy_file(self, src, dest, size=1024):
        """
        Exceedingly simple file copy.
        """

        if not self.debug:
            util.copy_file(src, dest, size)
        else:
            self.log.debug("Copy %s to %s" % (src, dest))

    def cmd_with_timeout(self, cmd, wname=None, timeout=None):
        """
        Run a command.  If debug is set, the action
        is only logged.  Commands are run without stdin, to avoid stray
        SIGTTINs. If timeout is given and the command runs longer, a
        cmd_timeout exception is thrown.
        """

        try:
            dnull = open("/dev/null", "w")
        except IOError:
            self.log.debug("[cmd_with_timeout]: failed to open /dev/null " + \
                    "for redirect")
            dnull = Null

        self.log.debug("[cmd_with_timeout]: %s" % cmd)
        if not self.debug:
            if dnull:
                sub = subprocess.Popen(cmd, shell=True, stdout=dnull,
                        stderr=dnull, close_fds=True)
            else:
                sub = subprocess.Popen(cmd, shell=True, close_fds=True)
            if timeout:
                i = 0
                rv = sub.poll()
                while i < timeout:
                    if rv is not None: break
                    else:
                        time.sleep(1)
                        rv = sub.poll()
                        i += 1
                else:
                    self.log.debug("Process exceeded runtime: %s" % cmd)
                    os.kill(sub.pid, signal.SIGKILL)
                    raise self.cmd_timeout();
                return rv == 0
            else:
                return sub.wait() == 0
        else:
            if timeout == 0:
                self.log.debug("debug timeout raised on %s " % cmd)
                raise self.cmd_timeout()
            else:
                return True

class start_segment(local_emulab_segment):
    def __init__(self, log=None, keyfile=None, debug=False):
        local_emulab_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 
"""

    def get_state(self, pid, eid):
        # 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 = [ expinfo_exec, pid, eid]

        dev_null = None
        try:
            dev_null = open("/dev/null", "a")
        except IOError, 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 __call__(self, parent, eid, pid, user, tclfile, tmpdir, timeout=0):
        """
        Start a sub-experiment on a federant.

        Get the current state, modify or create as appropriate, ship data
        and configs and start the experiment.  There are small ordering
        differences based on the initial state of the sub-experiment.
        """
        # Configuration directories on this machine
        proj_dir = "/proj/%s/exp/%s/tmp" % (pid, eid)
        softdir = "/proj/%s/software/%s" % (pid, eid)
        # Softwrae staging directory software dir
        lsoftdir = "%s/software" % tmpdir

        state = self.get_state(pid, eid)

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

            timedout = False
            try:
                if not self.cmd_with_timeout(
                        ("/usr/testbed/bin/startexp -i -f -w -p %s " + 
                        "-e %s %s/null.tcl") % (pid, eid, tmpdir), "startexp",
                        timeout=60 * 10):
                    return False
            except self.cmd_timeout:
                timedout = True

            if timedout:
                state = self.get_state(pid, eid)
                if state != "swapped":
                    return False
        
        # Set up the experiment's file space
        if not self.cmd_with_timeout("/bin/rm -rf %s" % proj_dir):
            return False
        # Clear and create the software and configuration directories
        if not self.cmd_with_timeout("/bin/rm -rf %s/*" % softdir):
            return False
        if not self.cmd_with_timeout('mkdir -p %s' % proj_dir):
            return False
        if os.path.isdir(lsoftdir):
            if not self.cmd_with_timeout('mkdir -p %s' % softdir):
                return False

        try:
            for f in os.listdir(tmpdir):
                if not os.path.isdir("%s/%s" % (tmpdir, f)):
                    self.copy_file("%s/%s" % (tmpdir, f), 
                            "%s/%s" % (proj_dir, f))
            if os.path.isdir(lsoftdir):
                for f in os.listdir(lsoftdir):
                    if not os.path.isdir("%s/%s" % (lsoftdir, f)):
                        self.copy_file("%s/%s" % (lsoftdir, f), 
                                "%s/%s" % (softdir, f))
        except IOError, e:
            self.log.error("Error copying file: %s" %e)
            return False

        # Stage the new configuration (active experiments will stay swapped
        # in now)
        self.log.info("[start_segment]: Modifying %s" % eid)
        try:
            if not self.cmd_with_timeout(
                    "/usr/testbed/bin/modexp -r -s -w %s %s %s" % \
                            (pid, eid, tclfile),
                    "modexp", timeout= 60 * 10):
                return False
        except self.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
        # Active experiments are still swapped, this swaps the others in.
        if state != 'active':
            self.log.info("[start_segment]: Swapping %s" % eid)
            timedout = False
            try:
                if not self.cmd_with_timeout(
                        "/usr/testbed/bin/swapexp -w %s %s in" % (pid, eid),
                        "swapexp", timeout=25*60):
                    return False
            except self.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(pid, eid)
                self.log.debug("[start_segment]: state is %s" % state)
                return state == 'active'
        # Everything has gone OK.
        return True

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

    def __call__(self, parent, user, pid, eid):
        """
        Stop a sub experiment by calling swapexp on the federant
        """
        self.log.info("[stop_segment]: Stopping %s" % eid)
        rv = False
        try:
            # Clean out tar files: we've gone over quota in the past
            self.cmd_with_timeout("rm -rf /proj/%s/software/%s" % (pid, eid))
            rv = self.cmd_with_timeout(
                    "/usr/testbed/bin/swapexp -w %s %s out" % (pid, eid), 
                    timeout = 60*10)
        except self.cmd_timeout:
            rv = False
        return rv