Synnefo

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import logging

from snf_django.lib.api import faults

from django.db import transaction

from synnefo import quotas

from synnefo.db import pools

from synnefo.db.models import (IPPoolTable, IPAddress, Network)

log = logging.getLogger(__name__)

def allocate_ip_from_pools(pool_rows, userid, address=None, floating_ip=False):

    """Try to allocate a value from a number of pools.

    This function takes as argument a number of PoolTable objects and tries to

    allocate a value from them. If all pools are empty EmptyPool is raised.

    If an address is specified and does not belong to any of the pools,

    InvalidValue is raised.

    """

    for pool_row in pool_rows:

        pool = pool_row.pool

        try:

            value = pool.get(value=address)

            pool.save()

            subnet = pool_row.subnet

            ipaddress = IPAddress.objects.create(subnet=subnet,

                                                 network=subnet.network,

                                                 userid=userid,

                                                 address=value,

                                                 floating_ip=floating_ip)

            return ipaddress

        except pools.EmptyPool:

            pass

        except pools.InvalidValue:

            pass

    if address is None:

        raise pools.EmptyPool("No more IP addresses available on pools %s" %

                              pool_rows)

    else:

        raise pools.InvalidValue("Address %s does not belong to pools %s" %

                                 (address, pool_rows))

def allocate_ip(network, userid, address=None, floating_ip=False):

    """Try to allocate an IP from networks IP pools."""

    if network.action == "DESTROY":

        raise faults.Conflict("Cannot allocate IP. Network %s is being"

                              " deleted" % network.id)

    elif network.drained:

        raise faults.Conflict("Can not allocate IP while network '%s' is in"

                              " 'SNF:DRAINED' status" % network.id)

    ip_pools = IPPoolTable.objects.select_for_update()\

        .filter(subnet__network=network)

    try:

        return allocate_ip_from_pools(ip_pools, userid, address=address,

                                      floating_ip=floating_ip)

    except pools.EmptyPool:

        raise faults.Conflict("No more IP addresses available on network %s"

                              % network.id)

    except pools.ValueNotAvailable:

        raise faults.Conflict("IP address %s is already used." % address)

    except pools.InvalidValue:

        raise faults.BadRequest("Address %s does not belong to network %s" %

                                (address, network.id))

def allocate_public_ip(userid, floating_ip=False, backend=None, networks=None):

    """Try to allocate a public or floating IP address.

    Try to allocate a a public IPv4 address from one of the available networks.

    If 'floating_ip' is set, only networks which are floating IP pools will be

    used and the IPAddress that will be created will be marked as a floating

    IP. If 'backend' is set, only the networks that exist in this backend will

    be used.

    """

    ip_pool_rows = IPPoolTable.objects.select_for_update()\

        .prefetch_related("subnet__network")\

        .filter(subnet__deleted=False)\

        .filter(subnet__network__deleted=False)\

        .filter(subnet__network__public=True)\

        .filter(subnet__network__drained=False)

    if networks is not None:

        ip_pool_rows = ip_pool_rows.filter(subnet__network__in=networks)

    if floating_ip:

        ip_pool_rows = ip_pool_rows\

            .filter(subnet__network__floating_ip_pool=True)

    if backend is not None:

        ip_pool_rows = ip_pool_rows\

            .filter(subnet__network__backend_networks__backend=backend)

    try:

        return allocate_ip_from_pools(ip_pool_rows, userid,

                                      floating_ip=floating_ip)

    except pools.EmptyPool:

        ip_type = "floating" if floating_ip else "public"

        log_msg = "Failed to allocate a %s IP. Reason:" % ip_type

        if ip_pool_rows:

            log_msg += " No network exists."

        else:

            log_msg += " All network are full."

        if backend is not None:

            log_msg += " Backend: %s" % backend

        log.error(log_msg)

        exception_msg = "Cannot allocate a %s IP address." % ip_type

        raise faults.Conflict(exception_msg)

@transaction.commit_on_success

def create_floating_ip(userid, network=None, address=None):

    if network is None:

        floating_ip = allocate_public_ip(userid, floating_ip=True)

    else:

        if not network.floating_ip_pool:

            msg = ("Cannot allocate floating IP. Network %s is"

                   " not a floating IP pool.")

            raise faults.Conflict(msg % network.id)

        if network.action == "DESTROY":

            msg = "Cannot allocate floating IP. Network %s is being deleted."

            raise faults.Conflict(msg % network.id)

        # Allocate the floating IP

        floating_ip = allocate_ip(network, userid, address=address,

                                  floating_ip=True)

    # Issue commission (quotas)

    quotas.issue_and_accept_commission(floating_ip)

    transaction.commit()

    log.info("Created floating IP '%s' for user IP '%s'", floating_ip, userid)

    return floating_ip

def get_free_floating_ip(userid, network=None):

    """Get one of the free available floating IPs of the user.

    Get one of the users floating IPs that is not connected to any port

    or server. If network is specified, the floating IP must be from

    that network.

    """

    floating_ips = IPAddress.objects\

                            .filter(userid=userid, deleted=False, nic=None,

                                    floating_ip=True)

    if network is not None:

        floating_ips = floating_ips.filter(network=network)

    for floating_ip in floating_ips:

        floating_ip = IPAddress.objects.select_for_update()\

                                       .get(id=floating_ip.id)

        if floating_ip.nic is None:

            return floating_ip

    msg = "Cannot find an unused floating IP to connect server to"

    if network is not None:

        msg += " network '%s'." % network.id

    else:

        msg += " a public network."

    msg += " Please create a floating IP."

    raise faults.Conflict(msg)

@transaction.commit_on_success

def delete_floating_ip(floating_ip):

    if floating_ip.nic:

        # This is safe, you also need for_update to attach floating IP to

        # instance.

        msg = "Floating IP '%s' is attached to instance." % floating_ip.id

        raise faults.Conflict(msg)

    # Lock network to prevent deadlock

    Network.objects.select_for_update().get(id=floating_ip.network_id)

    # Return the address of the floating IP back to pool

    floating_ip.release_address()

    # And mark the floating IP as deleted

    floating_ip.deleted = True

    floating_ip.save()

    # Release quota for floating IP

    quotas.issue_and_accept_commission(floating_ip, action="DESTROY")

    transaction.commit()

    # Delete the floating IP from DB

    log.info("Deleted floating IP '%s' of user '%s", floating_ip,

             floating_ip.userid)

    floating_ip.delete()