src/emuvim/api/sonata/dummygatekeeper.py

"""
Copyright (c) 2015 SONATA-NFV and Paderborn University
ALL RIGHTS RESERVED.

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.

Neither the name of the SONATA-NFV [, ANY ADDITIONAL AFFILIATION]
nor the names of its contributors may be used to endorse or promote
products derived from this software without specific prior written
permission.

This work has been performed in the framework of the SONATA project,
funded by the European Commission under Grant number 671517 through
the Horizon 2020 and 5G-PPP programmes. The authors would like to
acknowledge the contributions of their colleagues of the SONATA
partner consortium (www.sonata-nfv.eu).
"""
"""
This module implements a simple REST API that behaves like SONATA's gatekeeper.

It is only used to support the development of SONATA's SDK tools and to demonstrate
the year 1 version of the emulator until the integration with WP4's orchestrator is done.
"""

import logging
import os
import uuid
import hashlib
import zipfile
import yaml
import threading
from docker import DockerClient, APIClient
from flask import Flask, request
import flask_restful as fr
from collections import defaultdict
import pkg_resources
from subprocess import Popen
from random import randint
import ipaddress

logging.basicConfig()
LOG = logging.getLogger("sonata-dummy-gatekeeper")
LOG.setLevel(logging.DEBUG)
logging.getLogger("werkzeug").setLevel(logging.WARNING)

GK_STORAGE = "/tmp/son-dummy-gk/"
UPLOAD_FOLDER = os.path.join(GK_STORAGE, "uploads/")
CATALOG_FOLDER = os.path.join(GK_STORAGE, "catalog/")

# Enable Dockerfile build functionality
BUILD_DOCKERFILE = False

# flag to indicate that we run without the emulator (only the bare API for integration testing)
GK_STANDALONE_MODE = False

# should a new version of an image be pulled even if its available
FORCE_PULL = False

# Automatically deploy SAPs (endpoints) of the service as new containers
# Attention: This is not a configuration switch but a global variable! Don't change its default value.
DEPLOY_SAP = False

# flag to indicate if we use bidirectional forwarding rules in the automatic chaining process
BIDIRECTIONAL_CHAIN = False

# override the management interfaces in the descriptors with default docker0 interfaces in the containers
USE_DOCKER_MGMT = True

def generate_subnets(prefix, base, subnet_size=50, mask=24):
    # Generate a list of ipaddress in subnets
    r = list()
    for net in range(base, base + subnet_size):
        subnet = "{0}.{1}.0/{2}".format(prefix, net, mask)
        r.append(ipaddress.ip_network(unicode(subnet)))
    return r
# private subnet definitions for the generated interfaces
# 10.10.xxx.0/24
SAP_SUBNETS = generate_subnets('10.10', 0, subnet_size=50, mask=30)
# 10.20.xxx.0/30
ELAN_SUBNETS = generate_subnets('10.20', 0, subnet_size=50, mask=24)
# 10.30.xxx.0/30
ELINE_SUBNETS = generate_subnets('10.30', 0, subnet_size=50, mask=30)


class Gatekeeper(object):

    def __init__(self):
        self.services = dict()
        self.dcs = dict()
        self.net = None
        self.vnf_counter = 0  # used to generate short names for VNFs (Mininet limitation)
        LOG.info("Create SONATA dummy gatekeeper.")

    def register_service_package(self, service_uuid, service):
        """
        register new service package
        :param service_uuid
        :param service object
        """
        self.services[service_uuid] = service
        # lets perform all steps needed to onboard the service
        service.onboard()

    def get_next_vnf_name(self):
        self.vnf_counter += 1
        return "vnf%d" % self.vnf_counter


class Service(object):
    """
    This class represents a NS uploaded as a *.son package to the
    dummy gatekeeper.
    Can have multiple running instances of this service.
    """

    def __init__(self,
                 service_uuid,
                 package_file_hash,
                 package_file_path):
        self.uuid = service_uuid
        self.package_file_hash = package_file_hash
        self.package_file_path = package_file_path
        self.package_content_path = os.path.join(CATALOG_FOLDER, "services/%s" % self.uuid)
        self.manifest = None
        self.nsd = None
        self.vnfds = dict()
        self.saps = dict()
        self.saps_ext = list()
        self.saps_int = list()
        self.local_docker_files = dict()
        self.remote_docker_image_urls = dict()
        self.instances = dict()
        self.vnf_name2docker_name = dict()
        self.vnf_id2vnf_name = dict()

    def onboard(self):
        """
        Do all steps to prepare this service to be instantiated
        :return:
        """
        # 1. extract the contents of the package and store them in our catalog
        self._unpack_service_package()
        # 2. read in all descriptor files
        self._load_package_descriptor()
        self._load_nsd()
        self._load_vnfd()
        if DEPLOY_SAP:
            self._load_saps()
        # create dict to translate vnf names
        self.vnf_id2vnf_name = defaultdict(lambda: "NotExistingNode",
                                           reduce(lambda x, y: dict(x, **y),
                                                  map(lambda d: {d["vnf_id"]: d["vnf_name"]},
                                                      self.nsd["network_functions"])))
        # 3. prepare container images (e.g. download or build Dockerfile)
        if BUILD_DOCKERFILE:
            self._load_docker_files()
            self._build_images_from_dockerfiles()
        else:
            self._load_docker_urls()
            self._pull_predefined_dockerimages()
        LOG.info("On-boarded service: %r" % self.manifest.get("name"))

    def start_service(self):
        """
        This methods creates and starts a new service instance.
        It computes placements, iterates over all VNFDs, and starts
        each VNFD as a Docker container in the data center selected
        by the placement algorithm.
        :return:
        """
        LOG.info("Starting service %r" % self.uuid)

        # 1. each service instance gets a new uuid to identify it
        instance_uuid = str(uuid.uuid4())
        # build a instances dict (a bit like a NSR :))
        self.instances[instance_uuid] = dict()
        self.instances[instance_uuid]["vnf_instances"] = list()

        # 2. compute placement of this service instance (adds DC names to VNFDs)
        if not GK_STANDALONE_MODE:
            #self._calculate_placement(FirstDcPlacement)
            self._calculate_placement(RoundRobinDcPlacementWithSAPs)

        # 3. start all vnfds that we have in the service (except SAPs)
        for vnfd in self.vnfds.itervalues():
            vnfi = None
            if not GK_STANDALONE_MODE:
                vnfi = self._start_vnfd(vnfd)
            self.instances[instance_uuid]["vnf_instances"].append(vnfi)

        # 4. start all SAPs in the service
        for sap in self.saps:
            self._start_sap(self.saps[sap], instance_uuid)

        # 5. Deploy E-Line and E_LAN links
        if "virtual_links" in self.nsd:
            vlinks = self.nsd["virtual_links"]
            # constituent virtual links are not checked
            #fwd_links = self.nsd["forwarding_graphs"][0]["constituent_virtual_links"]
            eline_fwd_links = [l for l in vlinks if (l["connectivity_type"] == "E-Line")]
            elan_fwd_links = [l for l in vlinks if (l["connectivity_type"] == "E-LAN")]

            GK.net.deployed_elines.extend(eline_fwd_links)
            GK.net.deployed_elans.extend(elan_fwd_links)

            # 5a. deploy E-Line links
            self._connect_elines(eline_fwd_links, instance_uuid)

            # 5b. deploy E-LAN links
            self._connect_elans(elan_fwd_links, instance_uuid)

        # 6. run the emulator specific entrypoint scripts in the VNFIs of this service instance
        self._trigger_emulator_start_scripts_in_vnfis(self.instances[instance_uuid]["vnf_instances"])

        LOG.info("Service started. Instance id: %r" % instance_uuid)
        return instance_uuid

    def stop_service(self, instance_uuid):
        """
        This method stops a running service instance.
        It iterates over all VNF instances, stopping them each
        and removing them from their data center.

        :param instance_uuid: the uuid of the service instance to be stopped
        """
        LOG.info("Stopping service %r" % self.uuid)
        # get relevant information
        # instance_uuid = str(self.uuid.uuid4())
        vnf_instances = self.instances[instance_uuid]["vnf_instances"]

        for v in vnf_instances:
            self._stop_vnfi(v)

        if not GK_STANDALONE_MODE:
            # remove placement?
            # self._remove_placement(RoundRobinPlacement)
            None

        # last step: remove the instance from the list of all instances
        del self.instances[instance_uuid]

    def _start_vnfd(self, vnfd):
        """
        Start a single VNFD of this service
        :param vnfd: vnfd descriptor dict
        :return:
        """
        # iterate over all deployment units within each VNFDs
        for u in vnfd.get("virtual_deployment_units"):
            # 1. get the name of the docker image to start and the assigned DC
            vnf_name = vnfd.get("name")
            if vnf_name not in self.remote_docker_image_urls:
                raise Exception("No image name for %r found. Abort." % vnf_name)
            docker_name = self.remote_docker_image_urls.get(vnf_name)
            target_dc = vnfd.get("dc")
            # 2. perform some checks to ensure we can start the container
            assert(docker_name is not None)
            assert(target_dc is not None)
            if not self._check_docker_image_exists(docker_name):
                raise Exception("Docker image %r not found. Abort." % docker_name)

            # 3. get the resource limits
            res_req = u.get("resource_requirements")
            cpu_list = res_req.get("cpu").get("cores")
            if not cpu_list or len(cpu_list)==0:
                cpu_list="1"
            cpu_bw = res_req.get("cpu").get("cpu_bw")
            if not cpu_bw:
                cpu_bw=1
            mem_num = str(res_req.get("memory").get("size"))
            if len(mem_num)==0:
                mem_num="2"
            mem_unit = str(res_req.get("memory").get("size_unit"))
            if str(mem_unit)==0:
                mem_unit="GB"
            mem_limit = float(mem_num)
            if mem_unit=="GB":
                mem_limit=mem_limit*1024*1024*1024
            elif mem_unit=="MB":
                mem_limit=mem_limit*1024*1024
            elif mem_unit=="KB":
                mem_limit=mem_limit*1024
            mem_lim = int(mem_limit)
            cpu_period, cpu_quota = self._calculate_cpu_cfs_values(float(cpu_bw))

            vnf_name2id = defaultdict(lambda: "NotExistingNode",
                                      reduce(lambda x, y: dict(x, **y),
                                             map(lambda d: {d["vnf_name"]: d["vnf_id"]},
                                                 self.nsd["network_functions"])))

            # check if we need to deploy the management ports (defined as type:management both on in the vnfd and nsd)
            intfs = vnfd.get("connection_points", [])
            mgmt_intf_names = []
            if USE_DOCKER_MGMT:
                vnf_id = vnf_name2id[vnf_name]
                mgmt_intfs = [vnf_id + ':' + intf['id'] for intf in intfs if intf.get('type') == 'management']
                # check if any of these management interfaces are used in a management-type network in the nsd
                for nsd_intf_name in mgmt_intfs:
                    vlinks = [ l["connection_points_reference"] for l in self.nsd.get("virtual_links", [])]
                    for link in vlinks:
                        if nsd_intf_name in link and self.check_mgmt_interface(link):
                            # this is indeed a management interface and can be skipped
                            vnf_id, vnf_interface, vnf_sap_docker_name = parse_interface(nsd_intf_name)
                            found_interfaces = [intf for intf in intfs if intf.get('id') == vnf_interface]
                            intfs.remove(found_interfaces[0])
                            mgmt_intf_names.append(vnf_interface)

            # 4. generate the volume paths for the docker container
            volumes=list()
            # a volume to extract log files
            docker_log_path = "/tmp/results/%s/%s"%(self.uuid,vnf_name)
            LOG.debug("LOG path for vnf %s is %s."%(vnf_name,docker_log_path))
            if not os.path.exists(docker_log_path):
                LOG.debug("Creating folder %s"%docker_log_path)
                os.makedirs(docker_log_path)

            volumes.append(docker_log_path+":/mnt/share/")


            # 5. do the dc.startCompute(name="foobar") call to run the container
            # TODO consider flavors, and other annotations
            # TODO: get all vnf id's from the nsd for this vnfd and use those as dockername
            # use the vnf_id in the nsd as docker name
            # so deployed containers can be easily mapped back to the nsd

            self.vnf_name2docker_name[vnf_name] = vnf_name2id[vnf_name]

            LOG.info("Starting %r as %r in DC %r" % (vnf_name, self.vnf_name2docker_name[vnf_name], vnfd.get("dc")))
            LOG.debug("Interfaces for %r: %r" % (vnf_name, intfs))
            vnfi = target_dc.startCompute(
                    self.vnf_name2docker_name[vnf_name],
                    network=intfs,
                    image=docker_name,
                    flavor_name="small",
                    cpu_quota=cpu_quota,
                    cpu_period=cpu_period,
                    cpuset=cpu_list,
                    mem_limit=mem_lim,
                    volumes=volumes)

            # rename the docker0 interfaces (eth0) to the management port name defined in the VNFD
            if USE_DOCKER_MGMT:
                for intf_name in mgmt_intf_names:
                    self._vnf_reconfigure_network(vnfi, 'eth0', new_name=intf_name)

            return vnfi

    def _stop_vnfi(self, vnfi):
        """
        Stop a VNF instance.

        :param vnfi: vnf instance to be stopped
        """
        # Find the correct datacenter
        status = vnfi.getStatus()
        dc = vnfi.datacenter

        # stop the vnfi
        LOG.info("Stopping the vnf instance contained in %r in DC %r" % (status["name"], dc))
        dc.stopCompute(status["name"])

    def _get_vnf_instance(self, instance_uuid, name):
        """
        Returns the Docker object for the given VNF name (or Docker name).
        :param instance_uuid: UUID of the service instance to search in.
        :param name: VNF name or Docker name. We are fuzzy here.
        :return:
        """
        dn = name
        if name in self.vnf_name2docker_name:
            dn = self.vnf_name2docker_name[name]
        for vnfi in self.instances[instance_uuid]["vnf_instances"]:
            if vnfi.name == dn:
                return vnfi
        LOG.warning("No container with name: {0} found.".format(dn))
        return None

    @staticmethod
    def _vnf_reconfigure_network(vnfi, if_name, net_str=None, new_name=None):
        """
        Reconfigure the network configuration of a specific interface
        of a running container.
        :param vnfi: container instance
        :param if_name: interface name
        :param net_str: network configuration string, e.g., 1.2.3.4/24
        :return:
        """

        # assign new ip address
        if net_str is not None:
            intf = vnfi.intf(intf=if_name)
            if intf is not None:
                intf.setIP(net_str)
                LOG.debug("Reconfigured network of %s:%s to %r" % (vnfi.name, if_name, net_str))
            else:
                LOG.warning("Interface not found: %s:%s. Network reconfiguration skipped." % (vnfi.name, if_name))

        if new_name is not None:
            vnfi.cmd('ip link set', if_name, 'down')
            vnfi.cmd('ip link set', if_name, 'name', new_name)
            vnfi.cmd('ip link set', new_name, 'up')
            LOG.debug("Reconfigured interface name of %s:%s to %s" % (vnfi.name, if_name, new_name))



    def _trigger_emulator_start_scripts_in_vnfis(self, vnfi_list):
        for vnfi in vnfi_list:
            config = vnfi.dcinfo.get("Config", dict())
            env = config.get("Env", list())
            for env_var in env:
                var, cmd = map(str.strip, map(str, env_var.split('=', 1)))
                LOG.debug("%r = %r" % (var , cmd))
                if var=="SON_EMU_CMD":
                    LOG.info("Executing entry point script in %r: %r" % (vnfi.name, cmd))
                    # execute command in new thread to ensure that GK is not blocked by VNF
                    t = threading.Thread(target=vnfi.cmdPrint, args=(cmd,))
                    t.daemon = True
                    t.start()

    def _unpack_service_package(self):
        """
        unzip *.son file and store contents in CATALOG_FOLDER/services/<service_uuid>/
        """
        LOG.info("Unzipping: %r" % self.package_file_path)
        with zipfile.ZipFile(self.package_file_path, "r") as z:
            z.extractall(self.package_content_path)


    def _load_package_descriptor(self):
        """
        Load the main package descriptor YAML and keep it as dict.
        :return:
        """
        self.manifest = load_yaml(
            os.path.join(
                self.package_content_path, "META-INF/MANIFEST.MF"))

    def _load_nsd(self):
        """
        Load the entry NSD YAML and keep it as dict.
        :return:
        """
        if "entry_service_template" in self.manifest:
            nsd_path = os.path.join(
                self.package_content_path,
                make_relative_path(self.manifest.get("entry_service_template")))
            self.nsd = load_yaml(nsd_path)
            GK.net.deployed_nsds.append(self.nsd)

            LOG.debug("Loaded NSD: %r" % self.nsd.get("name"))

    def _load_vnfd(self):
        """
        Load all VNFD YAML files referenced in MANIFEST.MF and keep them in dict.
        :return:
        """
        if "package_content" in self.manifest:
            for pc in self.manifest.get("package_content"):
                if pc.get("content-type") == "application/sonata.function_descriptor":
                    vnfd_path = os.path.join(
                        self.package_content_path,
                        make_relative_path(pc.get("name")))
                    vnfd = load_yaml(vnfd_path)
                    self.vnfds[vnfd.get("name")] = vnfd
                    LOG.debug("Loaded VNFD: %r" % vnfd.get("name"))

    def _load_saps(self):
        # create list of all SAPs
        # check if we need to deploy management ports
        if USE_DOCKER_MGMT:
            LOG.debug("nsd: {0}".format(self.nsd))
            SAPs = [p for p in self.nsd["connection_points"] if 'management' not in p.get('type')]
        else:
            SAPs = [p for p in self.nsd["connection_points"]]

        for sap in SAPs:
            # endpoint needed in this service
            sap_id, sap_interface, sap_docker_name = parse_interface(sap['id'])
            # make sure SAP has type set (default internal)
            sap["type"] = sap.get("type", 'internal')

            # Each Service Access Point (connection_point) in the nsd is an IP address on the host
            if sap["type"] == "external":
                # add to vnfds to calculate placement later on
                sap_net = SAP_SUBNETS.pop(0)
                self.saps[sap_docker_name] = {"name": sap_docker_name , "type": "external", "net": sap_net}
                # add SAP vnf to list in the NSD so it is deployed later on
                # each SAP get a unique VNFD and vnf_id in the NSD and custom type (only defined in the dummygatekeeper)
                self.nsd["network_functions"].append(
                    {"vnf_id": sap_docker_name, "vnf_name": sap_docker_name, "vnf_type": "sap_ext"})

            # Each Service Access Point (connection_point) in the nsd is getting its own container (default)
            elif sap["type"] == "internal" or sap["type"] == "management":
                # add SAP to self.vnfds
                sapfile = pkg_resources.resource_filename(__name__, "sap_vnfd.yml")
                sap_vnfd = load_yaml(sapfile)
                sap_vnfd["connection_points"][0]["id"] = sap_interface
                sap_vnfd["name"] = sap_docker_name
                sap_vnfd["type"] = "internal"
                # add to vnfds to calculate placement later on and deploy
                self.saps[sap_docker_name] = sap_vnfd
                # add SAP vnf to list in the NSD so it is deployed later on
                # each SAP get a unique VNFD and vnf_id in the NSD
                self.nsd["network_functions"].append(
                    {"vnf_id": sap_docker_name, "vnf_name": sap_docker_name, "vnf_type": "sap_int"})

            LOG.debug("Loaded SAP: name: {0}, type: {1}".format(sap_docker_name, sap['type']))

        # create sap lists
        self.saps_ext = [self.saps[sap]['name'] for sap in self.saps if self.saps[sap]["type"] == "external"]
        self.saps_int = [self.saps[sap]['name'] for sap in self.saps if self.saps[sap]["type"] == "internal"]

    def _start_sap(self, sap, instance_uuid):
        if not DEPLOY_SAP:
            return

        LOG.info('start SAP: {0} ,type: {1}'.format(sap['name'],sap['type']))
        if sap["type"] == "internal":
            vnfi = None
            if not GK_STANDALONE_MODE:
                vnfi = self._start_vnfd(sap)
            self.instances[instance_uuid]["vnf_instances"].append(vnfi)

        elif sap["type"] == "external":
            target_dc = sap.get("dc")
            # add interface to dc switch
            target_dc.attachExternalSAP(sap['name'], sap['net'])

    def _connect_elines(self, eline_fwd_links, instance_uuid):
        """
        Connect all E-LINE links in the NSD
        :param eline_fwd_links: list of E-LINE links in the NSD
        :param: instance_uuid of the service
        :return:
        """
        # cookie is used as identifier for the flowrules installed by the dummygatekeeper
        # eg. different services get a unique cookie for their flowrules
        cookie = 1
        for link in eline_fwd_links:
            # check if we need to deploy this link when its a management link:
            if USE_DOCKER_MGMT:
                if self.check_mgmt_interface(link["connection_points_reference"]):
                    continue

            src_id, src_if_name, src_sap_id = parse_interface(link["connection_points_reference"][0])
            dst_id, dst_if_name, dst_sap_id = parse_interface(link["connection_points_reference"][1])

            setChaining = False
            # check if there is a SAP in the link and chain everything together
            if src_sap_id in self.saps and dst_sap_id in self.saps:
                LOG.info('2 SAPs cannot be chained together : {0} - {1}'.format(src_sap_id, dst_sap_id))
                continue

            elif src_sap_id in self.saps_ext:
                src_id = src_sap_id
                # set intf name to None so the chaining function will choose the first one
                src_if_name = None
                src_name = self.vnf_id2vnf_name[src_id]
                dst_name = self.vnf_id2vnf_name[dst_id]
                dst_vnfi = self._get_vnf_instance(instance_uuid, dst_name)
                if dst_vnfi is not None:
                    # choose first ip address in sap subnet
                    sap_net = self.saps[src_sap_id]['net']
                    sap_ip = "{0}/{1}".format(str(sap_net[2]), sap_net.prefixlen)
                    self._vnf_reconfigure_network(dst_vnfi, dst_if_name, sap_ip)
                    setChaining = True

            elif dst_sap_id in self.saps_ext:
                dst_id = dst_sap_id
                # set intf name to None so the chaining function will choose the first one
                dst_if_name = None
                src_name = self.vnf_id2vnf_name[src_id]
                dst_name = self.vnf_id2vnf_name[dst_id]
                src_vnfi = self._get_vnf_instance(instance_uuid, src_name)
                if src_vnfi is not None:
                    sap_net = self.saps[dst_sap_id]['net']
                    sap_ip = "{0}/{1}".format(str(sap_net[2]), sap_net.prefixlen)
                    self._vnf_reconfigure_network(src_vnfi, src_if_name, sap_ip)
                    setChaining = True

            # Link between 2 VNFs
            else:
                # make sure we use the correct sap vnf name
                if src_sap_id in self.saps_int:
                    src_id = src_sap_id
                if dst_sap_id in self.saps_int:
                    dst_id = dst_sap_id
                src_name = self.vnf_id2vnf_name[src_id]
                dst_name = self.vnf_id2vnf_name[dst_id]
                # re-configure the VNFs IP assignment and ensure that a new subnet is used for each E-Link
                src_vnfi = self._get_vnf_instance(instance_uuid, src_name)
                dst_vnfi = self._get_vnf_instance(instance_uuid, dst_name)
                if src_vnfi is not None and dst_vnfi is not None:
                    eline_net = ELINE_SUBNETS.pop(0)
                    ip1 = "{0}/{1}".format(str(eline_net[1]), eline_net.prefixlen)
                    ip2 = "{0}/{1}".format(str(eline_net[2]), eline_net.prefixlen)
                    self._vnf_reconfigure_network(src_vnfi, src_if_name, ip1)
                    self._vnf_reconfigure_network(dst_vnfi, dst_if_name, ip2)
                    setChaining = True

            # Set the chaining
            if setChaining:
                ret = GK.net.setChain(
                    src_id, dst_id,
                    vnf_src_interface=src_if_name, vnf_dst_interface=dst_if_name,
                    bidirectional=BIDIRECTIONAL_CHAIN, cmd="add-flow", cookie=cookie, priority=10)
                LOG.debug(
                    "Setting up E-Line link. %s(%s:%s) -> %s(%s:%s)" % (
                        src_name, src_id, src_if_name, dst_name, dst_id, dst_if_name))


    def _connect_elans(self, elan_fwd_links, instance_uuid):
        """
        Connect all E-LAN links in the NSD
        :param elan_fwd_links: list of E-LAN links in the NSD
        :param: instance_uuid of the service
        :return:
        """
        for link in elan_fwd_links:
            # check if we need to deploy this link when its a management link:
            if USE_DOCKER_MGMT:
                if self.check_mgmt_interface(link["connection_points_reference"]):
                    continue

            elan_vnf_list = []
            # check if an external SAP is in the E-LAN (then a subnet is already defined)
            intfs_elan = [intf for intf in link["connection_points_reference"]]
            lan_sap = self.check_ext_saps(intfs_elan)
            if lan_sap:
                lan_net = self.saps[lan_sap]['net']
                lan_hosts = list(lan_net.hosts())
                sap_ip = str(lan_hosts.pop(0))
            else:
                lan_net = ELAN_SUBNETS.pop(0)
                lan_hosts = list(lan_net.hosts())

            # generate lan ip address for all interfaces except external SAPs
            for intf in link["connection_points_reference"]:

                # skip external SAPs, they already have an ip
                vnf_id, vnf_interface, vnf_sap_docker_name = parse_interface(intf)
                if vnf_sap_docker_name in self.saps_ext:
                    elan_vnf_list.append({'name': vnf_sap_docker_name, 'interface': vnf_interface})
                    continue

                ip_address = "{0}/{1}".format(str(lan_hosts.pop(0)), lan_net.prefixlen)
                vnf_id, intf_name, vnf_sap_id = parse_interface(intf)

                # make sure we use the correct sap vnf name
                src_docker_name = vnf_id
                if vnf_sap_id in self.saps_int:
                    src_docker_name = vnf_sap_id
                    vnf_id = vnf_sap_id

                vnf_name = self.vnf_id2vnf_name[vnf_id]
                LOG.debug(
                    "Setting up E-LAN interface. %s(%s:%s) -> %s" % (
                        vnf_name, vnf_id, intf_name, ip_address))

                if vnf_name in self.vnfds:
                    # re-configure the VNFs IP assignment and ensure that a new subnet is used for each E-LAN
                    # E-LAN relies on the learning switch capability of Ryu which has to be turned on in the topology
                    # (DCNetwork(controller=RemoteController, enable_learning=True)), so no explicit chaining is necessary.
                    vnfi = self._get_vnf_instance(instance_uuid, vnf_name)
                    if vnfi is not None:
                        self._vnf_reconfigure_network(vnfi, intf_name, ip_address)
                        # add this vnf and interface to the E-LAN for tagging
                        elan_vnf_list.append({'name': src_docker_name, 'interface': intf_name})

            # install the VLAN tags for this E-LAN
            GK.net.setLAN(elan_vnf_list)


    def _load_docker_files(self):
        """
        Get all paths to Dockerfiles from VNFDs and store them in dict.
        :return:
        """
        for k, v in self.vnfds.iteritems():
            for vu in v.get("virtual_deployment_units"):
                if vu.get("vm_image_format") == "docker":
                    vm_image = vu.get("vm_image")
                    docker_path = os.path.join(
                        self.package_content_path,
                        make_relative_path(vm_image))
                    self.local_docker_files[k] = docker_path
                    LOG.debug("Found Dockerfile (%r): %r" % (k, docker_path))

    def _load_docker_urls(self):
        """
        Get all URLs to pre-build docker images in some repo.
        :return:
        """
        # also merge sap dicts, because internal saps also need a docker container
        all_vnfs = self.vnfds.copy()
        all_vnfs.update(self.saps)

        for k, v in all_vnfs.iteritems():
            for vu in v.get("virtual_deployment_units", {}):
                if vu.get("vm_image_format") == "docker":
                    url = vu.get("vm_image")
                    if url is not None:
                        url = url.replace("http://", "")
                        self.remote_docker_image_urls[k] = url
                        LOG.debug("Found Docker image URL (%r): %r" % (k, self.remote_docker_image_urls[k]))

    def _build_images_from_dockerfiles(self):
        """
        Build Docker images for each local Dockerfile found in the package: self.local_docker_files
        """
        if GK_STANDALONE_MODE:
            return  # do not build anything in standalone mode
        dc = DockerClient()
        LOG.info("Building %d Docker images (this may take several minutes) ..." % len(self.local_docker_files))
        for k, v in self.local_docker_files.iteritems():
            for line in dc.build(path=v.replace("Dockerfile", ""), tag=k, rm=False, nocache=False):
                LOG.debug("DOCKER BUILD: %s" % line)
            LOG.info("Docker image created: %s" % k)

    def _pull_predefined_dockerimages(self):
        """
        If the package contains URLs to pre-build Docker images, we download them with this method.
        """
        dc = DockerClient()
        for url in self.remote_docker_image_urls.itervalues():
            if not FORCE_PULL:  # only pull if not present (speedup for development)
                if len(dc.images.list(name=url)) > 0:
                    LOG.debug("Image %r present. Skipping pull." % url)
                    continue
            LOG.info("Pulling image: %r" % url)
            # this seems to fail with latest docker api version 2.0.2
            # dc.images.pull(url,
            #        insecure_registry=True)
            #using docker cli instead
            cmd = ["docker",
                   "pull",
                   url,
                   ]
            Popen(cmd).wait()




    def _check_docker_image_exists(self, image_name):
        """
        Query the docker service and check if the given image exists
        :param image_name: name of the docker image
        :return:
        """
        return len(DockerClient().images.list(name=image_name)) > 0

    def _calculate_placement(self, algorithm):
        """
        Do placement by adding the a field "dc" to
        each VNFD that points to one of our
        data center objects known to the gatekeeper.
        """
        assert(len(self.vnfds) > 0)
        assert(len(GK.dcs) > 0)
        # instantiate algorithm an place
        p = algorithm()
        p.place(self.nsd, self.vnfds, self.saps, GK.dcs)
        LOG.info("Using placement algorithm: %r" % p.__class__.__name__)
        # lets print the placement result
        for name, vnfd in self.vnfds.iteritems():
            LOG.info("Placed VNF %r on DC %r" % (name, str(vnfd.get("dc"))))
        for sap in self.saps:
            sap_dict = self.saps[sap]
            LOG.info("Placed SAP %r on DC %r" % (sap, str(sap_dict.get("dc"))))


    def _calculate_cpu_cfs_values(self, cpu_time_percentage):
        """
        Calculate cpu period and quota for CFS
        :param cpu_time_percentage: percentage of overall CPU to be used
        :return: cpu_period, cpu_quota
        """
        if cpu_time_percentage is None:
            return -1, -1
        if cpu_time_percentage < 0:
            return -1, -1
        # (see: https://www.kernel.org/doc/Documentation/scheduler/sched-bwc.txt)
        # Attention minimum cpu_quota is 1ms (micro)
        cpu_period = 1000000  # lets consider a fixed period of 1000000 microseconds for now
        LOG.debug("cpu_period is %r, cpu_percentage is %r" % (cpu_period, cpu_time_percentage))
        cpu_quota = cpu_period * cpu_time_percentage  # calculate the fraction of cpu time for this container
        # ATTENTION >= 1000 to avoid a invalid argument system error ... no idea why
        if cpu_quota < 1000:
            LOG.debug("cpu_quota before correcting: %r" % cpu_quota)
            cpu_quota = 1000
            LOG.warning("Increased CPU quota to avoid system error.")
        LOG.debug("Calculated: cpu_period=%f / cpu_quota=%f" % (cpu_period, cpu_quota))
        return int(cpu_period), int(cpu_quota)

    def check_ext_saps(self, intf_list):
        # check if the list of interfacs contains an externl SAP
        saps_ext = [self.saps[sap]['name'] for sap in self.saps if self.saps[sap]["type"] == "external"]
        for intf_name in intf_list:
            vnf_id, vnf_interface, vnf_sap_docker_name = parse_interface(intf_name)
            if vnf_sap_docker_name in saps_ext:
                return vnf_sap_docker_name

    def check_mgmt_interface(self, intf_list):
        SAPs_mgmt = [p.get('id') for p in self.nsd["connection_points"] if 'management' in p.get('type')]
        for intf_name in intf_list:
            if intf_name in SAPs_mgmt:
                return True

"""
Some (simple) placement algorithms
"""


class FirstDcPlacement(object):
    """
    Placement: Always use one and the same data center from the GK.dcs dict.
    """
    def place(self, nsd, vnfds, saps, dcs):
        for name, vnfd in vnfds.iteritems():
            vnfd["dc"] = list(dcs.itervalues())[0]


class RoundRobinDcPlacement(object):
    """
    Placement: Distribute VNFs across all available DCs in a round robin fashion.
    """
    def place(self, nsd, vnfds, saps, dcs):
        c = 0
        dcs_list = list(dcs.itervalues())
        for name, vnfd in vnfds.iteritems():
            vnfd["dc"] = dcs_list[c % len(dcs_list)]
            c += 1  # inc. c to use next DC

class RoundRobinDcPlacementWithSAPs(object):
    """
    Placement: Distribute VNFs across all available DCs in a round robin fashion,
    every SAP is instantiated on the same DC as the connected VNF.
    """
    def place(self, nsd, vnfds, saps, dcs):

        # place vnfs
        c = 0
        dcs_list = list(dcs.itervalues())
        for name, vnfd in vnfds.iteritems():
            vnfd["dc"] = dcs_list[c % len(dcs_list)]
            c += 1  # inc. c to use next DC

        # place SAPs
        vlinks = nsd.get("virtual_links", [])
        eline_fwd_links = [l for l in vlinks if (l["connectivity_type"] == "E-Line")]
        elan_fwd_links = [l for l in vlinks if  (l["connectivity_type"] == "E-LAN")]

        vnf_id2vnf_name = defaultdict(lambda: "NotExistingNode",
                                      reduce(lambda x, y: dict(x, **y),
                                             map(lambda d: {d["vnf_id"]: d["vnf_name"]},
                                                 nsd["network_functions"])))

        # SAPs on E-Line links are placed on the same DC as the VNF on the E-Line
        for link in eline_fwd_links:
            src_id, src_if_name, src_sap_id = parse_interface(link["connection_points_reference"][0])
            dst_id, dst_if_name, dst_sap_id = parse_interface(link["connection_points_reference"][1])

            # check if there is a SAP in the link
            if src_sap_id in saps:
                dst_vnf_name = vnf_id2vnf_name[dst_id]
                # get dc where connected vnf is mapped to
                dc = vnfds[dst_vnf_name]['dc']
                saps[src_sap_id]['dc'] = dc

            if dst_sap_id in saps:
                src_vnf_name = vnf_id2vnf_name[src_id]
                # get dc where connected vnf is mapped to
                dc = vnfds[src_vnf_name]['dc']
                saps[dst_sap_id]['dc'] = dc

        # SAPs on E-LANs are placed on a random DC
        dcs_list = list(dcs.itervalues())
        dc_len = len(dcs_list)
        for link in elan_fwd_links:
            for intf in link["connection_points_reference"]:
                # find SAP interfaces
                intf_id, intf_name, intf_sap_id = parse_interface(intf)
                if intf_sap_id in saps:
                    dc = dcs_list[randint(0, dc_len-1)]
                    saps[intf_sap_id]['dc'] = dc



"""
Resource definitions and API endpoints
"""


class Packages(fr.Resource):

    def post(self):
        """
        Upload a *.son service package to the dummy gatekeeper.

        We expect request with a *.son file and store it in UPLOAD_FOLDER
        :return: UUID
        """
        try:
            # get file contents
            LOG.info("POST /packages called")
            # lets search for the package in the request
            is_file_object = False  # make API more robust: file can be in data or in files field
            if "package" in request.files:
                son_file = request.files["package"]
                is_file_object = True
            elif len(request.data) > 0:
                son_file = request.data
            else:
                return {"service_uuid": None, "size": 0, "sha1": None, "error": "upload failed. file not found."}, 500
            # generate a uuid to reference this package
            service_uuid = str(uuid.uuid4())
            file_hash = hashlib.sha1(str(son_file)).hexdigest()
            # ensure that upload folder exists
            ensure_dir(UPLOAD_FOLDER)
            upload_path = os.path.join(UPLOAD_FOLDER, "%s.son" % service_uuid)
            # store *.son file to disk
            if is_file_object:
                son_file.save(upload_path)
            else:
                with open(upload_path, 'wb') as f:
                    f.write(son_file)
            size = os.path.getsize(upload_path)
            # create a service object and register it
            s = Service(service_uuid, file_hash, upload_path)
            GK.register_service_package(service_uuid, s)
            # generate the JSON result
            return {"service_uuid": service_uuid, "size": size, "sha1": file_hash, "error": None}, 201
        except Exception as ex:
            LOG.exception("Service package upload failed:")
            return {"service_uuid": None, "size": 0, "sha1": None, "error": "upload failed"}, 500

    def get(self):
        """
        Return a list of UUID's of uploaded service packages.
        :return: dict/list
        """
        LOG.info("GET /packages")
        return {"service_uuid_list": list(GK.services.iterkeys())}


class Instantiations(fr.Resource):

    def post(self):
        """
        Instantiate a service specified by its UUID.
        Will return a new UUID to identify the running service instance.
        :return: UUID
        """
        LOG.info("POST /instantiations (or /requests) called")
        # try to extract the service uuid from the request
        json_data = request.get_json(force=True)
        service_uuid = json_data.get("service_uuid")

        # lets be a bit fuzzy here to make testing easier
        if (service_uuid is None or service_uuid=="latest") and len(GK.services) > 0:
            # if we don't get a service uuid, we simple start the first service in the list
            service_uuid = list(GK.services.iterkeys())[0]
        if service_uuid in GK.services:
            # ok, we have a service uuid, lets start the service
            service_instance_uuid = GK.services.get(service_uuid).start_service()
            return {"service_instance_uuid": service_instance_uuid}, 201
        return "Service not found", 404

    def get(self):
        """
        Returns a list of UUIDs containing all running services.
        :return: dict / list
        """
        LOG.info("GET /instantiations")
        return {"service_instantiations_list": [
            list(s.instances.iterkeys()) for s in GK.services.itervalues()]}

    def delete(self):
        """
        Stops a running service specified by its service and instance UUID.
        """
        # try to extract the service  and instance UUID from the request
        json_data = request.get_json(force=True)
        service_uuid = json_data.get("service_uuid")
        instance_uuid = json_data.get("service_instance_uuid")

        # try to be fuzzy
        if service_uuid is None and len(GK.services) > 0:
            #if we don't get a service uuid, we simply stop the last service in the list
            service_uuid = list(GK.services.iterkeys())[0]
        if instance_uuid is None and len(GK.services[service_uuid].instances) > 0:
            instance_uuid = list(GK.services[service_uuid].instances.iterkeys())[0]

        if service_uuid in GK.services and instance_uuid in GK.services[service_uuid].instances:
            # valid service and instance UUID, stop service
            GK.services.get(service_uuid).stop_service(instance_uuid)
            return "service instance with uuid %r stopped." % instance_uuid,200
        return "Service not found", 404

class Exit(fr.Resource):

    def put(self):
        """
        Stop the running Containernet instance regardless of data transmitted
        """
        list(GK.dcs.values())[0].net.stop()


def initialize_GK():
    global GK
    GK = Gatekeeper()



# create a single, global GK object
GK = None
initialize_GK()
# setup Flask
app = Flask(__name__)
app.config['MAX_CONTENT_LENGTH'] = 512 * 1024 * 1024  # 512 MB max upload
api = fr.Api(app)
# define endpoints
api.add_resource(Packages, '/packages', '/api/v2/packages')
api.add_resource(Instantiations, '/instantiations', '/api/v2/instantiations', '/api/v2/requests')
api.add_resource(Exit, '/emulator/exit')



def start_rest_api(host, port, datacenters=dict()):
    GK.dcs = datacenters
    GK.net = get_dc_network()
    # start the Flask server (not the best performance but ok for our use case)
    app.run(host=host,
            port=port,
            debug=True,
            use_reloader=False  # this is needed to run Flask in a non-main thread
            )


def ensure_dir(name):
    if not os.path.exists(name):
        os.makedirs(name)


def load_yaml(path):
    with open(path, "r") as f:
        try:
            r = yaml.load(f)
        except yaml.YAMLError as exc:
            LOG.exception("YAML parse error")
            r = dict()
    return r


def make_relative_path(path):
    if path.startswith("file://"):
        path = path.replace("file://", "", 1)
    if path.startswith("/"):
        path = path.replace("/", "", 1)
    return path


def get_dc_network():
    """
    retrieve the DCnetwork where this dummygatekeeper (GK) connects to.
    Assume at least 1 datacenter is connected to this GK, and that all datacenters belong to the same DCNetwork
    :return:
    """
    assert (len(GK.dcs) > 0)
    return GK.dcs.values()[0].net


def parse_interface(interface_name):
    """
    convert the interface name in the nsd to the according vnf_id, vnf_interface names
    :param interface_name:
    :return:
    """

    if ':' in interface_name:
        vnf_id, vnf_interface = interface_name.split(':')
        vnf_sap_docker_name = interface_name.replace(':', '_')
    else:
        vnf_id = interface_name
        vnf_interface = interface_name
        vnf_sap_docker_name = interface_name

    return vnf_id, vnf_interface, vnf_sap_docker_name

if __name__ == '__main__':
    """
    Lets allow to run the API in standalone mode.
    """
    GK_STANDALONE_MODE = True
    logging.getLogger("werkzeug").setLevel(logging.INFO)
    start_rest_api("0.0.0.0", 8000)