source: fedd/federation/proxy_emulab_segment.py @ ab3d6c5

#!/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), 'active')
                    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