#!/usr/bin/env python
#
# xapi plugin script to update the cache of configuration items in the
# ovs-vswitchd configuration file that are managed in the xapi database
# when integrated with Citrix management tools.

# Copyright (C) 2009 Nicira Networks, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# TBD: - error handling needs to be improved.  Currently this can leave
# TBD:   the system in a bad state if anything goes wrong.

import logging
log = logging.getLogger("vswitch-cfg-update")
logging.basicConfig(filename="/var/log/vswitch-cfg-update.log", level=logging.DEBUG)

import XenAPIPlugin
import XenAPI
import os
import subprocess

cfg_mod="/root/vswitch/bin/ovs-cfg-mod"
vswitchd_cfg_filename="/etc/ovs-vswitchd.conf"
cacert_filename="/etc/ovs-vswitchd.cacert"

# Delete the CA certificate, so that we go back to boot-strapping mode
def delete_cacert():
    try:
        os.remove(cacert_filename)
    except OSError:
        # Ignore error if file doesn't exist
        pass

def update(session, args):
    pools = session.xenapi.pool.get_all()
    # We assume there is only ever one pool...
    if len(pools) == 0:
        log.error("No pool for host.")
        raise XenAPIPlugin.Failure("NO_POOL_FOR_HOST", [])
    if len(pools) > 1:
        log.error("More than one pool for host.")
        raise XenAPIPlugin.Failure("MORE_THAN_ONE_POOL_FOR_HOST", [])
    pool = session.xenapi.pool.get_record(pools[0])
    try:
        controller = pool["other_config"]["vSwitchController"]
    except KeyError, e:
        controller = ""
    currentController = vswitchCurrentController()
    if controller == "" and currentController != "":
        log.debug("Removing controller configuration.")
        delete_cacert()
        removeControllerCfg()
        return "Successfully removed controller config"
    elif controller != currentController:
        if len(controller) == 0:
            log.debug("Setting controller to: %s" % (controller))
        else:
            log.debug("Changing controller from %s to %s" % (currentController, controller))
        delete_cacert()
        setControllerCfg(controller)
        return "Successfully set controller to " + controller
    else:
        log.debug("No change to controller configuration required.")
    return "No change to configuration"
        
def vswitchCurrentController():
    controller = vswitchCfgQuery("mgmt.controller")
    if controller == "":
        return controller
    if len(controller) < 4 or controller[0:4] != "ssl:":
        log.warning("Controller does not specify ssl connection type, returning entire string.")
        return controller
    else:
        return controller[4:]

def removeControllerCfg():
    vswitchCfgMod(["--del-match", "mgmt.controller=*",
                   "--del-match", "ssl.bootstrap-ca-cert=*",
                   "--del-match", "ssl.ca-cert=*",
                   "--del-match", "ssl.private-key=*",
                   "--del-match", "ssl.certificate=*"])
                                       
def setControllerCfg(controller):
    vswitchCfgMod(["--del-match", "mgmt.controller=*",
                   "--del-match", "ssl.bootstrap-ca-cert=*",
                   "--del-match", "ssl.ca-cert=*",
                   "--del-match", "ssl.private-key=*",
                   "--del-match", "ssl.certificate=*",
                   "-a", "mgmt.controller=ssl:" + controller,
                   "-a", "ssl.bootstrap-ca-cert=true",
                   "-a", "ssl.ca-cert=/etc/ovs-vswitchd.cacert",
                   "-a", "ssl.private-key=/etc/xensource/xapi-ssl.pem",
                   "-a", "ssl.certificate=/etc/xensource/xapi-ssl.pem"])

def vswitchCfgQuery(key):
    cmd = [cfg_mod, "--config-file=" + vswitchd_cfg_filename, "-q", key]
    output = subprocess.Popen(cmd, stdout=subprocess.PIPE).communicate()
    if len(output) == 0 or output[0] == None:
        output = ""
    else:
        output = output[0].strip()
    return output

def vswitchCfgMod(action_args):
    cmd = [cfg_mod, "-vANY:console:emer",
           "--config-file=" + vswitchd_cfg_filename] + action_args
    exitcode = subprocess.call(cmd)
    if exitcode != 0:
        log.error("ovs-cfg-mod failed with exit code "
                  + str(exitcode) + " for " + repr(action_args))
        raise XenAPIPlugin.Failure("VSWITCH_CONFIG_MOD_FAILURE",
                                   [ str(exitcode) , str(action_args) ])
    vswitchReload()
    
def vswitchReload():
    exitcode = subprocess.call(["/sbin/service", "vswitch", "reload"])
    if exitcode != 0:
        log.error("vswitch reload failed with exit code " + str(exitcode))
        raise XenAPIPlugin.Failure("VSWITCH_CFG_RELOAD_FAILURE", [ str(exitcode) ])
    

if __name__ == "__main__":
    XenAPIPlugin.dispatch({"update": update})