Synnefo

# Copyright 2011-2012 GRNET S.A. All rights reserved.

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import datetime

import ipaddr

from base64 import b64encode, b64decode

from datetime import timedelta, tzinfo

from functools import wraps

from hashlib import sha256

from logging import getLogger

from random import choice

from string import digits, lowercase, uppercase

from time import time

from traceback import format_exc

from wsgiref.handlers import format_date_time

import dateutil.parser

from Crypto.Cipher import AES

from django.conf import settings

from django.http import HttpResponse

from django.template.loader import render_to_string

from django.utils import simplejson as json

from django.utils.cache import add_never_cache_headers

from django.db.models import Q

from snf_django.lib.api import faults

from synnefo.db.models import (Flavor, VirtualMachine, VirtualMachineMetadata,

                               Network, BackendNetwork, NetworkInterface,

                               BridgePoolTable, MacPrefixPoolTable, Backend)

from synnefo.db.pools import EmptyPool

from snf_django.lib.astakos import get_user

from synnefo.plankton.utils import image_backend

from synnefo.settings import MAX_CIDR_BLOCK

log = getLogger('synnefo.api')

def random_password():

    """Generates a random password

    We generate a windows compliant password: it must contain at least

    one charachter from each of the groups: upper case, lower case, digits.

    """

    pool = lowercase + uppercase + digits

    lowerset = set(lowercase)

    upperset = set(uppercase)

    digitset = set(digits)

    length = 10

    password = ''.join(choice(pool) for i in range(length - 2))

    # Make sure the password is compliant

    chars = set(password)

    if not chars & lowerset:

        password += choice(lowercase)

    if not chars & upperset:

        password += choice(uppercase)

    if not chars & digitset:

        password += choice(digits)

    # Pad if necessary to reach required length

    password += ''.join(choice(pool) for i in range(length - len(password)))

    return password

def zeropad(s):

    """Add zeros at the end of a string in order to make its length

       a multiple of 16."""

    npad = 16 - len(s) % 16

    return s + '\x00' * npad

def encrypt(plaintext):

    # Make sure key is 32 bytes long

    key = sha256(settings.SECRET_KEY).digest()

    aes = AES.new(key)

    enc = aes.encrypt(zeropad(plaintext))

    return b64encode(enc)

def get_vm(server_id, user_id, for_update=False, non_deleted=False,

           non_suspended=False):

    """Find a VirtualMachine instance based on ID and owner."""

    try:

        server_id = int(server_id)

        servers = VirtualMachine.objects

        if for_update:

            servers = servers.select_for_update()

        vm = servers.get(id=server_id, userid=user_id)

        if non_deleted and vm.deleted:

            raise VirtualMachine.DeletedError

        if non_suspended and vm.suspended:

            raise faults.Forbidden("Administratively Suspended VM")

        return vm

    except ValueError:

        raise faults.BadRequest('Invalid server ID.')

    except VirtualMachine.DoesNotExist:

        raise faults.ItemNotFound('Server not found.')

def get_vm_meta(vm, key):

    """Return a VirtualMachineMetadata instance or raise ItemNotFound."""

    try:

        return VirtualMachineMetadata.objects.get(meta_key=key, vm=vm)

    except VirtualMachineMetadata.DoesNotExist:

        raise faults.ItemNotFound('Metadata key not found.')

def get_image(image_id, user_id):

    """Return an Image instance or raise ItemNotFound."""

    with image_backend(user_id) as backend:

        return backend.get_image(image_id)

def get_image_dict(image_id, user_id):

    image = {}

    img = get_image(image_id, user_id)

    properties = img.get('properties', {})

    image['backend_id'] = img['location']

    image['format'] = img['disk_format']

    image['metadata'] = dict((key.upper(), val)

                             for key, val in properties.items())

    image['checksum'] = img['checksum']

    return image

def get_flavor(flavor_id, include_deleted=False):

    """Return a Flavor instance or raise ItemNotFound."""

    try:

        flavor_id = int(flavor_id)

        if include_deleted:

            return Flavor.objects.get(id=flavor_id)

        else:

            return Flavor.objects.get(id=flavor_id, deleted=include_deleted)

    except (ValueError, Flavor.DoesNotExist):

        raise faults.ItemNotFound('Flavor not found.')

def get_flavor_provider(flavor):

    """Extract provider from disk template.

    Provider for `ext` disk_template is encoded in the disk template

    name, which is formed `ext_<provider_name>`. Provider is None

    for all other disk templates.

    """

    disk_template = flavor.disk_template

    provider = None

    if disk_template.startswith("ext"):

        disk_template, provider = disk_template.split("_", 1)

    return disk_template, provider

def get_network(network_id, user_id, for_update=False):

    """Return a Network instance or raise ItemNotFound."""

    try:

        network_id = int(network_id)

        objects = Network.objects

        if for_update:

            objects = objects.select_for_update()

        return objects.get(Q(userid=user_id) | Q(public=True), id=network_id)

    except (ValueError, Network.DoesNotExist):

        raise faults.ItemNotFound('Network not found.')

def validate_network_params(subnet, gateway=None, subnet6=None, gateway6=None):

    try:

        # Use strict option to not all subnets with host bits set

        network = ipaddr.IPv4Network(subnet, strict=True)

    except ValueError:

        raise faults.BadRequest("Invalid network IPv4 subnet")

    # Check that network size is allowed!

    if not validate_network_size(network.prefixlen):

        raise faults.OverLimit(message="Unsupported network size",

                        details="Network mask must be in range (%s, 29]" %

                                MAX_CIDR_BLOCK)

    # Check that gateway belongs to network

    if gateway:

        try:

            gateway = ipaddr.IPv4Address(gateway)

        except ValueError:

            raise faults.BadRequest("Invalid network IPv4 gateway")

        if not gateway in network:

            raise faults.BadRequest("Invalid network IPv4 gateway")

    if subnet6:

        try:

            # Use strict option to not all subnets with host bits set

            network6 = ipaddr.IPv6Network(subnet6, strict=True)

        except ValueError:

            raise faults.BadRequest("Invalid network IPv6 subnet")

        if gateway6:

            try:

                gateway6 = ipaddr.IPv6Address(gateway6)

            except ValueError:

                raise faults.BadRequest("Invalid network IPv6 gateway")

            if not gateway6 in network6:

                raise faults.BadRequest("Invalid network IPv6 gateway")

def validate_network_size(cidr_block):

    """Return True if network size is allowed."""

    return cidr_block <= 29 and cidr_block > MAX_CIDR_BLOCK

def allocate_public_address(backend):

    """Allocate a public IP for a vm."""

    for network in backend_public_networks(backend):

        try:

            address = get_network_free_address(network)

            return (network, address)

        except EmptyPool:

            pass

    return (None, None)

def get_public_ip(backend):

    """Reserve an IP from a public network.

    This method should run inside a transaction.

    """

    # Guarantee exclusive access to backend, because accessing the IP pools of

    # the backend networks may result in a deadlock with backend allocator

    # which also checks that backend networks have a free IP.

    backend = Backend.objects.select_for_update().get(id=backend.id)

    address = None

    if settings.PUBLIC_USE_POOL:

        (network, address) = allocate_public_address(backend)

    else:

        for net in list(backend_public_networks(backend)):

            pool = net.get_pool()

            if not pool.empty():

                address = 'pool'

                network = net

                break

    if address is None:

        log.error("Public networks of backend %s are full", backend)

        raise faults.OverLimit("Can not allocate IP for new machine."

                        " Public networks are full.")

    return (network, address)

def backend_public_networks(backend):

    """Return available public networks of the backend.

    Iterator for non-deleted public networks that are available

    to the specified backend.

    """

    for network in Network.objects.filter(public=True, deleted=False):

        if BackendNetwork.objects.filter(network=network,

                                         backend=backend).exists():

            yield network

def get_network_free_address(network):

    """Reserve an IP address from the IP Pool of the network.

    Raises EmptyPool

    """

    pool = network.get_pool()

    address = pool.get()

    pool.save()

    return address

def get_nic(machine, network):

    try:

        return NetworkInterface.objects.get(machine=machine, network=network)

    except NetworkInterface.DoesNotExist:

        raise faults.ItemNotFound('Server not connected to this network.')

def get_nic_from_index(vm, nic_index):

    """Returns the nic_index-th nic of a vm

       Error Response Codes: itemNotFound (404), badMediaType (415)

    """

    matching_nics = vm.nics.filter(index=nic_index)

    matching_nics_len = len(matching_nics)

    if matching_nics_len < 1:

        raise faults.ItemNotFound('NIC not found on VM')

    elif matching_nics_len > 1:

        raise faults.BadMediaType('NIC index conflict on VM')

    nic = matching_nics[0]

    return nic

def render_metadata(request, metadata, use_values=False, status=200):

    if request.serialization == 'xml':

        data = render_to_string('metadata.xml', {'metadata': metadata})

    else:

        if use_values:

            d = {'metadata': {'values': metadata}}

        else:

            d = {'metadata': metadata}

        data = json.dumps(d)

    return HttpResponse(data, status=status)

def render_meta(request, meta, status=200):

    if request.serialization == 'xml':

        data = render_to_string('meta.xml', dict(key=key, val=val))

    else:

        data = json.dumps(dict(meta=meta))

    return HttpResponse(data, status=status)

def construct_nic_id(nic):

    return "-".join(["nic", unicode(nic.machine.id), unicode(nic.index)])

def verify_personality(personality):

    """Verify that a a list of personalities is well formed"""

    if len(personality) > settings.MAX_PERSONALITY:

        raise faults.OverLimit("Maximum number of personalities"

                        " exceeded")

    for p in personality:

        # Verify that personalities are well-formed

        try:

            assert isinstance(p, dict)

            keys = set(p.keys())

            allowed = set(['contents', 'group', 'mode', 'owner', 'path'])

            assert keys.issubset(allowed)

            contents = p['contents']

            if len(contents) > settings.MAX_PERSONALITY_SIZE:

                # No need to decode if contents already exceed limit

                raise faults.OverLimit("Maximum size of personality exceeded")

            if len(b64decode(contents)) > settings.MAX_PERSONALITY_SIZE:

                raise faults.OverLimit("Maximum size of personality exceeded")

        except AssertionError:

            raise faults.BadRequest("Malformed personality in request")

def values_from_flavor(flavor):

    """Get Ganeti connectivity info from flavor type.

    If link or mac_prefix equals to "pool", then the resources

    are allocated from the corresponding Pools.

    """

    try:

        flavor = Network.FLAVORS[flavor]

    except KeyError:

        raise faults.BadRequest("Unknown network flavor")

    mode = flavor.get("mode")

    link = flavor.get("link")

    if link == "pool":

        link = allocate_resource("bridge")

    mac_prefix = flavor.get("mac_prefix")

    if mac_prefix == "pool":

        mac_prefix = allocate_resource("mac_prefix")

    tags = flavor.get("tags")

    return mode, link, mac_prefix, tags

def allocate_resource(res_type):

    table = get_pool_table(res_type)

    pool = table.get_pool()

    value = pool.get()

    pool.save()

    return value

def release_resource(res_type, value):

    table = get_pool_table(res_type)

    pool = table.get_pool()

    pool.put(value)

    pool.save()

def get_pool_table(res_type):

    if res_type == "bridge":

        return BridgePoolTable

    elif res_type == "mac_prefix":

        return MacPrefixPoolTable

    else:

        raise Exception("Unknown resource type")

def get_existing_users():

    """

    Retrieve user ids stored in cyclades user agnostic models.

    """

    # also check PublicKeys a user with no servers/networks exist

    from synnefo.ui.userdata.models import PublicKeyPair

    from synnefo.db.models import VirtualMachine, Network

    keypairusernames = PublicKeyPair.objects.filter().values_list('user',

                                                                  flat=True)

    serverusernames = VirtualMachine.objects.filter().values_list('userid',

                                                                  flat=True)

    networkusernames = Network.objects.filter().values_list('userid',

                                                            flat=True)

    return set(list(keypairusernames) + list(serverusernames) +

               list(networkusernames))