base.py

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"""
Provides base classes for working with drivers
"""
import httplib, urllib
import time
import hashlib
import StringIO
import ssl
import os
import socket
import struct

from libcloud.common.base import ConnectionKey, ConnectionUserAndKey
from libcloud.compute.types import NodeState, DeploymentError
from libcloud.compute.ssh import SSHClient
from libcloud.httplib_ssl import LibcloudHTTPSConnection
from httplib import HTTPConnection as LibcloudHTTPConnection

class Node(object):
    """
    Provide a common interface for handling nodes of all types.

    The Node object provides the interface in libcloud through which
    we can manipulate nodes in different cloud providers in the same
    way.  Node objects don't actually do much directly themselves,
    instead the node driver handles the connection to the node.

    You don't normally create a node object yourself; instead you use
    a driver and then have that create the node for you.

    >>> from libcloud.compute.drivers.dummy import DummyNodeDriver
    >>> driver = DummyNodeDriver(0)
    >>> node = driver.create_node()
    >>> node.public_ip[0]
    '127.0.0.3'
    >>> node.name
    'dummy-3'

    You can also get nodes from the driver's list_node function.

    >>> node = driver.list_nodes()[0]
    >>> node.name
    'dummy-1'

    the node keeps a reference to its own driver which means that we
    can work on nodes from different providers without having to know
    which is which.

    >>> driver = DummyNodeDriver(72)
    >>> node2 = driver.create_node()
    >>> node.driver.creds
    0
    >>> node2.driver.creds
    72

    Althrough Node objects can be subclassed, this isn't normally
    done.  Instead, any driver specific information is stored in the
    "extra" proproperty of the node.

    >>> node.extra
    {'foo': 'bar'}

    """

    def __init__(self, id, name, state, public_ip, private_ip,
                 driver, extra=None):
        self.id = str(id) if id else None
        self.name = name
        self.state = state
        self.public_ip = public_ip
        self.private_ip = private_ip
        self.driver = driver
        self.uuid = self.get_uuid()
        if not extra:
            self.extra = {}
        else:
            self.extra = extra

    def get_uuid(self):
        """Unique hash for this node

        @return: C{string}

        The hash is a function of an SHA1 hash of the node's ID and
        its driver which means that it should be unique between all
        nodes.  In some subclasses (e.g. GoGrid) there is no ID
        available so the public IP address is used.  This means that,
        unlike a properly done system UUID, the same UUID may mean a
        different system install at a different time

        >>> from libcloud.compute.drivers.dummy import DummyNodeDriver
        >>> driver = DummyNodeDriver(0)
        >>> node = driver.create_node()
        >>> node.get_uuid()
        'd3748461511d8b9b0e0bfa0d4d3383a619a2bb9f'

        Note, for example, that this example will always produce the
        same UUID!
        """
        return hashlib.sha1("%s:%d" % (self.id,self.driver.type)).hexdigest()

    def reboot(self):
        """Reboot this node

        @return: C{bool}

        This calls the node's driver and reboots the node

        >>> from libcloud.compute.drivers.dummy import DummyNodeDriver
        >>> driver = DummyNodeDriver(0)
        >>> node = driver.create_node()
        >>> from libcloud.compute.types import NodeState
        >>> node.state == NodeState.RUNNING
        True
        >>> node.state == NodeState.REBOOTING
        False
        >>> node.reboot()
        True
        >>> node.state == NodeState.REBOOTING
        True
        """
        return self.driver.reboot_node(self)

    def destroy(self):
        """Destroy this node

        @return: C{bool}

        This calls the node's driver and destroys the node

        >>> from libcloud.compute.drivers.dummy import DummyNodeDriver
        >>> driver = DummyNodeDriver(0)
        >>> from libcloud.compute.types import NodeState
        >>> node = driver.create_node()
        >>> node.state == NodeState.RUNNING
        True
        >>> node.destroy()
        True
        >>> node.state == NodeState.RUNNING
        False

        """
        return self.driver.destroy_node(self)

    def __repr__(self):
        return (('<Node: uuid=%s, name=%s, state=%s, public_ip=%s, '
                 'provider=%s ...>')
                % (self.uuid, self.name, self.state, self.public_ip,
                   self.driver.name))


class NodeSize(object):
    """
    A Base NodeSize class to derive from.

    NodeSizes are objects which are typically returned a driver's
    list_sizes function.  They contain a number of different
    parameters which define how big an image is.

    The exact parameters available depends on the provider.

    N.B. Where a parameter is "unlimited" (for example bandwidth in
    Amazon) this will be given as 0.

    >>> from libcloud.compute.drivers.dummy import DummyNodeDriver
    >>> driver = DummyNodeDriver(0)
    >>> size = driver.list_sizes()[0]
    >>> size.ram
    128
    >>> size.bandwidth
    500
    >>> size.price
    4
    """

    def __init__(self, id, name, ram, disk, bandwidth, price, driver):
        self.id = str(id)
        self.name = name
        self.ram = ram
        self.disk = disk
        self.bandwidth = bandwidth
        self.price = price
        self.driver = driver
    def __repr__(self):
        return (('<NodeSize: id=%s, name=%s, ram=%s disk=%s bandwidth=%s '
                 'price=%s driver=%s ...>')
                % (self.id, self.name, self.ram, self.disk, self.bandwidth,
                   self.price, self.driver.name))


class NodeImage(object):
    """
    An operating system image.

    NodeImage objects are typically returned by the driver for the
    cloud provider in response to the list_images function

    >>> from libcloud.compute.drivers.dummy import DummyNodeDriver
    >>> driver = DummyNodeDriver(0)
    >>> image = driver.list_images()[0]
    >>> image.name
    'Ubuntu 9.10'

    Apart from name and id, there is no further standard information;
    other parameters are stored in a driver specific "extra" variable

    When creating a node, a node image should be given as an argument
    to the create_node function to decide which OS image to use.

    >>> node = driver.create_node(image=image)

    """

    def __init__(self, id, name, driver, extra=None):
        self.id = str(id)
        self.name = name
        self.driver = driver
        if not extra:
            self.extra = {}
        else:
            self.extra = extra
    def __repr__(self):
        return (('<NodeImage: id=%s, name=%s, driver=%s  ...>')
                % (self.id, self.name, self.driver.name))

class NodeLocation(object):
    """
    A physical location where nodes can be.

    >>> from libcloud.compute.drivers.dummy import DummyNodeDriver
    >>> driver = DummyNodeDriver(0)
    >>> location = driver.list_locations()[0]
    >>> location.country
    'US'
    """

    def __init__(self, id, name, country, driver):
        self.id = str(id)
        self.name = name
        self.country = country
        self.driver = driver
    def __repr__(self):
        return (('<NodeLocation: id=%s, name=%s, country=%s, driver=%s>')
                % (self.id, self.name, self.country, self.driver.name))

class NodeAuthSSHKey(object):
    """
    An SSH key to be installed for authentication to a node.

    This is the actual contents of the users ssh public key which will
    normally be installed as root's public key on the node.

    >>> pubkey = '...' # read from file
    >>> from libcloud.compute.base import NodeAuthSSHKey
    >>> k = NodeAuthSSHKey(pubkey)
    >>> k
    <NodeAuthSSHKey>

    """
    def __init__(self, pubkey):
        self.pubkey = pubkey
    def __repr__(self):
        return '<NodeAuthSSHKey>'

class NodeAuthPassword(object):
    """
    A password to be used for authentication to a node.
    """
    def __init__(self, password):
        self.password = password
    def __repr__(self):
        return '<NodeAuthPassword>'

class NodeDriver(object):
    """
    A base NodeDriver class to derive from

    This class is always subclassed by a specific driver.  For
    examples of base behavior of most functions (except deploy node)
    see the dummy driver.

    """

    connectionCls = ConnectionKey
    name = None
    type = None
    port = None
    features = {"create_node": []}
    """
    List of available features for a driver.
        - L{create_node}
            - ssh_key: Supports L{NodeAuthSSHKey} as an authentication method
              for nodes.
            - password: Supports L{NodeAuthPassword} as an authentication
              method for nodes.
            - generates_password: Returns a password attribute on the Node
              object returned from creation.
    """

    NODE_STATE_MAP = {}

    def __init__(self, key, secret=None, secure=True, host=None, port=None):
        """
        @keyword    key:    API key or username to used
        @type       key:    str

        @keyword    secret: Secret password to be used
        @type       secret: str

        @keyword    secure: Weither to use HTTPS or HTTP. Note: Some providers
                            only support HTTPS, and it is on by default.
        @type       secure: bool

        @keyword    host: Override hostname used for connections.
        @type       host: str

        @keyword    port: Override port used for connections.
        @type       port: int
        """
        self.key = key
        self.secret = secret
        self.secure = secure
        args = [self.key]

        if self.secret != None:
            args.append(self.secret)

        args.append(secure)

        if host != None:
            args.append(host)

        if port != None:
            args.append(port)

        self.connection = self.connectionCls(*args)

        self.connection.driver = self
        self.connection.connect()

    def create_node(self, **kwargs):
        """Create a new node instance.

        @keyword    name:   String with a name for this new node (required)
        @type       name:   str

        @keyword    size:   The size of resources allocated to this node.
                            (required)
        @type       size:   L{NodeSize}

        @keyword    image:  OS Image to boot on node. (required)
        @type       image:  L{NodeImage}

        @keyword    location: Which data center to create a node in. If empty,
                              undefined behavoir will be selected. (optional)
        @type       location: L{NodeLocation}

        @keyword    auth:   Initial authentication information for the node
                            (optional)
        @type       auth:   L{NodeAuthSSHKey} or L{NodeAuthPassword}

        @return: The newly created L{Node}.
        """
        raise NotImplementedError, \
            'create_node not implemented for this driver'

    def destroy_node(self, node):
        """Destroy a node.

        Depending upon the provider, this may destroy all data associated with
        the node, including backups.

        @return: C{bool} True if the destroy was successful, otherwise False
        """
        raise NotImplementedError, \
            'destroy_node not implemented for this driver'

    def reboot_node(self, node):
        """
        Reboot a node.
        @return: C{bool} True if the reboot was successful, otherwise False
        """
        raise NotImplementedError, \
            'reboot_node not implemented for this driver'

    def list_nodes(self):
        """
        List all nodes
        @return: C{list} of L{Node} objects
        """
        raise NotImplementedError, \
            'list_nodes not implemented for this driver'

    def list_images(self, location=None):
        """
        List images on a provider
        @return: C{list} of L{NodeImage} objects
        """
        raise NotImplementedError, \
            'list_images not implemented for this driver'

    def list_sizes(self, location=None):
        """
        List sizes on a provider
        @return: C{list} of L{NodeSize} objects
        """
        raise NotImplementedError, \
            'list_sizes not implemented for this driver'

    def list_locations(self):
        """
        List data centers for a provider
        @return: C{list} of L{NodeLocation} objects
        """
        raise NotImplementedError, \
            'list_locations not implemented for this driver'

    def deploy_node(self, **kwargs):
        """
        Create a new node, and start deployment.

        Depends on a Provider Driver supporting either using a specific password
        or returning a generated password.

        This function may raise a L{DeploymentException}, if a create_node
        call was successful, but there is a later error (like SSH failing or
        timing out).  This exception includes a Node object which you may want
        to destroy if incomplete deployments are not desirable.

        @keyword    deploy: Deployment to run once machine is online and availble to SSH.
        @type       deploy: L{Deployment}

        @keyword    ssh_username: Optional name of the account which is used when connecting to
                                  SSH server (default is root)
        @type       ssh_username: C{str}

        @keyword    ssh_port: Optional SSH server port (default is 22)
        @type       ssh_port: C{int}

        See L{NodeDriver.create_node} for more keyword args.

        >>> from libcloud.compute.drivers.dummy import DummyNodeDriver
        >>> from libcloud.deployment import ScriptDeployment, MultiStepDeployment
        >>> from libcloud.compute.base import NodeAuthSSHKey
        >>> driver = DummyNodeDriver(0)
        >>> key = NodeAuthSSHKey('...') # read from file
        >>> script = ScriptDeployment("yum -y install emacs strace tcpdump")
        >>> msd = MultiStepDeployment([key, script])
        >>> def d():
        ...     try:
        ...         node = driver.deploy_node(deploy=msd)
        ...     except NotImplementedError:
        ...         print "not implemented for dummy driver"
        >>> d()
        not implemented for dummy driver

        Deploy node is typically not overridden in subclasses.  The
        existing implementation should be able to handle most such.
        """
        # TODO: support ssh keys
        WAIT_PERIOD=3
        password = None

        if 'generates_password' not in self.features["create_node"]:
            if 'password' not in self.features["create_node"]:
                raise NotImplementedError, \
                    'deploy_node not implemented for this driver'

            if not kwargs.has_key('auth'):
                kwargs['auth'] = NodeAuthPassword(os.urandom(16).encode('hex'))

            password = kwargs['auth'].password
        node = self.create_node(**kwargs)
        try:
          if 'generates_password' in self.features["create_node"]:
              password = node.extra.get('password')
          start = time.time()
          end = start + (60 * 15)
          while time.time() < end:
              # need to wait until we get a public IP address.
              # TODO: there must be a better way of doing this
              time.sleep(WAIT_PERIOD)
              nodes = self.list_nodes()
              nodes = filter(lambda n: n.uuid == node.uuid, nodes)
              if len(nodes) == 0:
                  raise DeploymentError(node, "Booted node[%s] is missing form list_nodes." % node)
              if len(nodes) > 1:
                  raise DeploymentError(node, "Booted single node[%s], but multiple nodes have same UUID"% node)

              node = nodes[0]

              if node.public_ip is not None and node.public_ip != "" and node.state == NodeState.RUNNING:
                  break

          ssh_username = kwargs.get('ssh_username', 'root')
          ssh_port = kwargs.get('ssh_port', 22)

          client = SSHClient(hostname=node.public_ip[0],
                             port=ssh_port, username=ssh_username,
                             password=password)
          laste = None
          while time.time() < end:
              laste = None
              try:
                  client.connect()
                  break
              except (IOError, socket.gaierror, socket.error), e:
                  laste = e
              time.sleep(WAIT_PERIOD)
          if laste is not None:
              raise e

          tries = 3
          while tries >= 0:
            try:
              n = kwargs["deploy"].run(node, client)
              client.close()
              break
            except Exception, e:
              tries -= 1
              if tries == 0:
                raise
              client.connect()

        except DeploymentError, e:
          raise
        except Exception, e:
          raise DeploymentError(node, e)
        return n

def is_private_subnet(ip):
    """
    Utility function to check if an IP address is inside a private subnet.

    @type ip: C{str}
    @keyword ip: IP address to check

    @return: C{bool} if the specified IP address is private.
    """
    priv_subnets = [ {'subnet': '10.0.0.0', 'mask': '255.0.0.0'},
                     {'subnet': '172.16.0.0', 'mask': '255.240.0.0'},
                     {'subnet': '192.168.0.0', 'mask': '255.255.0.0'} ]

    ip = struct.unpack('I',socket.inet_aton(ip))[0]

    for network in priv_subnets:
        subnet = struct.unpack('I',socket.inet_aton(network['subnet']))[0]
        mask = struct.unpack('I',socket.inet_aton(network['mask']))[0]

        if (ip & mask) == (subnet & mask):
            return True

    return False


if __name__ == "__main__":
    import doctest
    doctest.testmod()