77 lines
2.3 KiB
Python
77 lines
2.3 KiB
Python
import yaml
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import sys
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from . import network, container
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class YamlTopology:
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""" Parse a YAML description of a network topology. The networks' links and domains
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are contained in the `links` and `domains` attributes, but their `create` methods
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are not called. """
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class InvalidConfiguration(Exception):
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def __init__(self, reason):
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self.reason = reason
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def __str__(self):
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return "Bad topology configuration: {}".format(self.reason)
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def __init__(self, path, conn):
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self.path = path
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self.conn = conn
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self.domains = None
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self.links = None
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self._parse()
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def _parse(self):
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with open(self.path, "r") as handle:
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topology = yaml.safe_load(handle)
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if "links" not in topology:
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raise self.InvalidConfiguration("links definition is mandatory")
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link_descr = topology["links"]
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self.links = []
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dom_descr = {}
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for link_conf in link_descr:
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if "domains" not in link_conf:
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raise self.InvalidConfiguration(
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"a 'domains' attribute is mandatory for each link"
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)
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cur_link = network.Network(self.conn)
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self.links.append(cur_link)
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for dom in link_conf["domains"]:
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if dom not in dom_descr:
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dom_descr[dom] = {"links": []}
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dom_descr[dom]["links"].append(cur_link)
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for dom_conf_name in topology.get("domains", None):
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if dom_conf_name not in dom_descr:
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# Domain does not participate in any link: warn and ignore
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print(
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(
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"WARNING: domain {} does not participate in any link. "
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"Ignored."
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).format(dom_conf_name),
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file=sys.stderr,
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)
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continue
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dom_conf = topology["domains"][dom_conf_name]
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dom_descr[dom_conf_name]["enable_v4"] = dom_conf.get("enable_v4", True)
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sorted_dom_names = sorted(list(dom_descr.keys()))
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self.domains = [
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container.Container(
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self.conn,
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dom_descr[dom]["links"],
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enable_v4=dom_descr[dom].get("enable_v4", True),
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)
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for dom in sorted_dom_names
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]
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