ironic-python-agent/ironic_python_agent/hardware.py

# Copyright 2013 Rackspace, 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.

import abc
import functools
import os

import psutil
import six
import stevedore

from ironic_python_agent import encoding
from ironic_python_agent.openstack.common import log
from ironic_python_agent import utils

_global_manager = None


class HardwareSupport(object):
    """These are just guidelines to suggest values that might be returned by
    calls to `evaluate_hardware_support`. No HardwareManager in mainline
    ironic-python-agent will ever offer a value greater than `MAINLINE`.
    Service Providers should feel free to return values greater than
    SERVICE_PROVIDER to distinguish between additional levels of support.
    """
    NONE = 0
    GENERIC = 1
    MAINLINE = 2
    SERVICE_PROVIDER = 3


class HardwareType(object):
    MAC_ADDRESS = 'mac_address'


class BlockDevice(encoding.Serializable):
    serializable_fields = ('name', 'size')

    def __init__(self, name, size):
        self.name = name
        self.size = size


class NetworkInterface(encoding.Serializable):
    serializable_fields = ('name', 'mac_address', 'switch_port_descr',
                           'switch_chassis_descr')

    def __init__(self, name, mac_addr):
        self.name = name
        self.mac_address = mac_addr
        # TODO(russellhaering): Pull these from LLDP
        self.switch_port_descr = None
        self.switch_chassis_descr = None


class CPU(encoding.Serializable):
    serializable_fields = ('model_name', 'frequency', 'count')

    def __init__(self, model_name, frequency, count):
        self.model_name = model_name
        self.frequency = frequency
        self.count = count


class Memory(encoding.Serializable):
    serializable_fields = ('total', )

    def __init__(self, total):
        self.total = total


@six.add_metaclass(abc.ABCMeta)
class HardwareManager(object):
    @abc.abstractmethod
    def evaluate_hardware_support(cls):
        pass

    @abc.abstractmethod
    def list_network_interfaces(self):
        pass

    @abc.abstractmethod
    def get_os_install_device(self):
        pass

    def list_hardware_info(self):
        hardware_info = {}
        hardware_info['interfaces'] = self.list_network_interfaces()
        hardware_info['cpu'] = self.get_cpus()
        hardware_info['disks'] = self.list_block_devices()
        hardware_info['memory'] = self.get_memory()
        return hardware_info


class GenericHardwareManager(HardwareManager):
    def __init__(self):
        self.sys_path = '/sys'

        if os.path.isdir('/mnt/sys'):
            self.sys_path = '/mnt/sys'

    def evaluate_hardware_support(cls):
        return HardwareSupport.GENERIC

    def _get_interface_info(self, interface_name):
        addr_path = '{0}/class/net/{1}/address'.format(self.sys_path,
                                                     interface_name)
        with open(addr_path) as addr_file:
            mac_addr = addr_file.read().strip()

        return NetworkInterface(interface_name, mac_addr)

    def _is_device(self, interface_name):
        device_path = '{0}/class/net/{1}/device'.format(self.sys_path,
                                                      interface_name)
        return os.path.exists(device_path)

    def list_network_interfaces(self):
        iface_names = os.listdir('{0}/class/net'.format(self.sys_path))
        return [self._get_interface_info(name)
                for name in iface_names
                if self._is_device(name)]

    def get_cpus(self):
        model = None
        freq = None
        with open('/proc/cpuinfo') as f:
            lines = f.read()
            for line in lines.split('\n'):
                if model and freq:
                    break
                if not model and line.startswith('model name'):
                    model = line.split(':')[1].strip()
                if not freq and line.startswith('cpu MHz'):
                    freq = line.split(':')[1].strip()

        return CPU(model, freq, psutil.cpu_count())

    def get_memory(self):
        # psutil returns a long, force it to an int
        return Memory(int(psutil.phymem_usage().total))

    def list_block_devices(self):
        report = utils.execute('blockdev', '--report',
                               check_exit_code=[0])[0]
        lines = report.split('\n')
        lines = [line.split() for line in lines if line != '']
        startsec_idx = lines[0].index('StartSec')
        device_idx = lines[0].index('Device')
        size_idx = lines[0].index('Size')
        # If a device doesn't start at sector 0, assume it is a partition
        return [BlockDevice(line[device_idx],
                            int(line[size_idx]))
                for line
                in lines[1:] if int(line[startsec_idx]) == 0]

    def get_os_install_device(self):
        # Find the first device larger than 4GB, assume it is the OS disk
        # TODO(russellhaering): This isn't a valid assumption in all cases,
        #                       is there a more reasonable default behavior?
        block_devices = self.list_block_devices()
        block_devices.sort(key=lambda device: device.size)
        for device in block_devices:
            if device.size >= (4 * pow(1024, 3)):
                return device.name


def _compare_extensions(ext1, ext2):
    mgr1 = ext1.obj
    mgr2 = ext2.obj
    return mgr1.evaluate_hardware_support() - mgr2.evaluate_hardware_support()


def get_manager():
    global _global_manager

    if not _global_manager:
        LOG = log.getLogger()
        extension_manager = stevedore.ExtensionManager(
            namespace='ironic_python_agent.hardware_managers',
            invoke_on_load=True)

        # There will always be at least one extension available (the
        # GenericHardwareManager).
        if six.PY2:
            preferred_extension = sorted(
                    extension_manager,
                    _compare_extensions)[0]
        else:
            preferred_extension = sorted(
                    extension_manager,
                    key=functools.cmp_to_key(_compare_extensions))[0]

        preferred_manager = preferred_extension.obj

        if preferred_manager.evaluate_hardware_support() <= 0:
            raise RuntimeError('No suitable HardwareManager could be found')

        LOG.info('selected hardware manager {0}'.format(
                 preferred_extension.entry_point_target))

        _global_manager = preferred_manager

    return _global_manager